09.10.24
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09.10.24

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Questions and Answers

What are the parts of a generalized neuron?

Cell body, dendrites, axon, axon terminal, myelin sheath.

Which part of the neuron is responsible for receiving information?

  • Myelin sheath
  • Dendrites (correct)
  • Axon
  • Cell body

    • What are glial cells, and what are their roles?

    Glial cells protect and support neurons; roles include structural support, transport of substances, and communication.

    What is a membrane potential?

    <p>A difference in charge between the inside and outside of a cell.</p> Signup and view all the answers

    What causes depolarization in a neuron?

    <p>Opening of sodium channels allowing sodium ions into the cell.</p> Signup and view all the answers

    What occurs during repolarization in a neuron?

    <p>Sodium channels close and potassium channels open, allowing potassium to move out of the cell.</p> Signup and view all the answers

    How does myelin increase the rate of conduction of axons?

    <p>Myelin creates a vacuum-like tunnel for the action potential to travel quickly along the axon.</p> Signup and view all the answers

    Which division of the nervous system controls voluntary actions?

    <p>Somatic nervous system</p> Signup and view all the answers

    Match the following cranial nerves with their functions:

    <p>I Olfactory = Smell II Optic = Vision VII Facial = Taste from anterior 2/3 of the tongue VIII Auditory = Hearing, balance</p> Signup and view all the answers

    What are the sensory functions of the auditory system?

    <p>Hearing and balance.</p> Signup and view all the answers

    Reflex testing can indicate damage to the CNS or PNS.

    <p>True</p> Signup and view all the answers

    What is the function of taste (gustation)?

    <p>To determine the type of food and identify whether it is good or bad.</p> Signup and view all the answers

    Muscle is stretched by _____ tapping tendon in knee.

    <p>hammer</p> Signup and view all the answers

    What is the main function of the ossicles?

    <p>They enhance and transmit sound from the eardrum to the cochlea.</p> Signup and view all the answers

    What are the two types of hair cells in the cochlea?

    <p>Outer hair cells and inner hair cells.</p> Signup and view all the answers

    What role does the Eustachian tube play?

    <p>It equalizes air pressure and drains mucus from the ear.</p> Signup and view all the answers

    What are the three sensations carried by afferent neurons in spinal nerves?

    <p>Touch, pain, and proprioception.</p> Signup and view all the answers

    Which of these is NOT a type of spinal nerve?

    <p>Nasal</p> Signup and view all the answers

    Plexuses are networks of intersecting nerves formed by spinal nerves.

    <p>True</p> Signup and view all the answers

    What two factors can lead to an increase in intracranial pressure (ICP)?

    <p>Inflammation and hemorrhage.</p> Signup and view all the answers

    What is the primary function of the spinothalamic tract?

    <p>Carries sensory impulses from perceptions of pain and temperature</p> Signup and view all the answers

    What is the Circle of Willis?

    <p>It's a backup system for blood supply to the brain.</p> Signup and view all the answers

    Which part of the brain is responsible for temperature regulation?

    <p>Midbrain</p> Signup and view all the answers

    The blood-brain barrier allows all substances to enter the brain freely.

    <p>False</p> Signup and view all the answers

    What neurotransmitter is particularly involved in the transfer of sensory information?

    <p>Glutamate.</p> Signup and view all the answers

    What is the effect when two drugs with similar effects are combined?

    <p>Synergistic Effect</p> Signup and view all the answers

    What can happen when Digoxin and Verapamil are used together?

    <p>Toxic levels and potentially fatal arrhythmia</p> Signup and view all the answers

    What is the term for the effect when one drug enhances the effect of another without having an effect itself?

    <p>Potentiating Effect</p> Signup and view all the answers

    Antibiotic overuse can lead to the development of drug resistance.

    <p>True</p> Signup and view all the answers

    What are the major classes of antidepressant drugs?

    <p>MAOIs, tricyclics, SSRIs, NSRIs, SNRIs, NDRIs</p> Signup and view all the answers

    What neurotransmitter is involved in learning and memory?

    <p>Acetylcholine</p> Signup and view all the answers

    Which neurotransmitter is associated with mood disorders such as manic depression?

    <p>Noradrenaline</p> Signup and view all the answers

    What is the mechanism of action of NSAIDs?

    <p>Inhibit the enzyme cyclooxygenase (COX)</p> Signup and view all the answers

    Lithium is used to treat mania by _______ mood.

    <p>stabilizing</p> Signup and view all the answers

    What are two major classes of analgesic drugs?

    <p>Non-steroidal analgesics (NSAIDs) and Narcotic analgesics (opiates)</p> Signup and view all the answers

    What happens when lymphoma treatment with chemotherapy is administered?

    <p>Destroys fast-growing cancer and some healthy cells</p> Signup and view all the answers

    What may occur as a side effect of narcotic analgesics?

    <p>Constipation, respiratory depression</p> Signup and view all the answers

    What are basophils responsible for?

    <p>Promotion of allergic responses and augmentation of anti-parasitic immunity</p> Signup and view all the answers

    What do Toll-Like Receptors do?

    <p>Recognize antigens and recruit immune response</p> Signup and view all the answers

    What are interferons?

    <p>Cytokines released by host cells to alert neighboring cells and combat infections</p> Signup and view all the answers

    The ______ activates the immune system response.

    <p>Complement</p> Signup and view all the answers

    What are the three pathways that activate the complement system?

    <p>Classical pathway, alternative pathway, lectin pathway</p> Signup and view all the answers

    Which cells are involved in humoral immunity?

    <p>Helper T cells</p> Signup and view all the answers

    T cells are produced in the ______ and mature in the ______.

    <p>Bone marrow, thymus</p> Signup and view all the answers

    B cells can directly recognize and deactivate antigens.

    <p>True</p> Signup and view all the answers

    What is the function of plasma cells?

    <p>To produce identical antibodies to an antigen</p> Signup and view all the answers

    Which antibody is predominant in saliva, mucus, milk, and tears?

    <p>IgA</p> Signup and view all the answers

    What is the role of the amygdala?

    <p>Hub for fear and aggression, involved in emotional learning.</p> Signup and view all the answers

    How does the amygdala affect individuals with damage?

    <p>They can't show fear or recognize it in others, may avoid eye contact, and cannot assess risky behaviors.</p> Signup and view all the answers

    What is the primary function of the hippocampus?

    <p>Conversion of short-term to long-term memory and memory for place.</p> Signup and view all the answers

    What are the two major branches of pharmacology?

    <p>Pharmacodynamics and pharmacokinetics.</p> Signup and view all the answers

    Define bioavailability.

    <p>The proportion of a drug administered which enters circulation and can have an active effect.</p> Signup and view all the answers

    What is an agonist?

    <p>A drug that binds to a receptor and activates cellular activity.</p> Signup and view all the answers

    What is an antagonist?

    <p>A drug that blocks receptors from other substances.</p> Signup and view all the answers

    List the four main pharmacokinetic processes.

    <p>Absorption, distribution, metabolism, excretion.</p> Signup and view all the answers

    What can affect drug absorption?

    <p>Route of administration, physiological state, and chemical properties of the drug.</p> Signup and view all the answers

    How can drug interactions affect absorption?

    <p>A drug may increase or decrease the absorption of another drug.</p> Signup and view all the answers

    What is therapeutic index?

    <p>A comparison of the amount of a therapeutic agent that causes the therapeutic effect to the amount that causes toxicity.</p> Signup and view all the answers

    What are classic signs of an opioid overdose? (Select all that apply)

    <p>Hypotension</p> Signup and view all the answers

    What is the treatment for an opioid overdose?

    <p>Use an opioid antagonist, e.g. naloxone or naltrexone.</p> Signup and view all the answers

    Define tolerance in relation to drug use.

    <p>Tolerance is the body’s state of reduced sensitivity to a drug due to regular doses.</p> Signup and view all the answers

    What does dependence refer to?

    <p>Dependence is the physiological or psychological adaptation of the body to the presence of a drug.</p> Signup and view all the answers

    What is neurotransmitter reuptake?

    <p>Reuptake is the process by which neurotransmitters in the synaptic cleft re-enter the presynaptic neuron.</p> Signup and view all the answers

    Match the following types of microorganisms with their characteristics:

    <p>Fungi = Eukaryotic organisms with a rigid cell wall of chitin and glucans Protozoa = Unicellular eukaryotes with membrane-bound organelles Bacteria = Unicellular prokaryotes with no nucleus Viruses = Microorganisms with RNA or DNA but no cellular structure</p> Signup and view all the answers

    What is the difference between gram-positive and gram-negative bacteria?

    <p>Gram-positive bacteria have a thick peptidoglycan layer, while gram-negative bacteria have a thin peptidoglycan layer covered by an outer membrane.</p> Signup and view all the answers

    Describe the structure of a virion.

    <p>A virion is composed of viral DNA or RNA surrounded by a protein shell (capsid).</p> Signup and view all the answers

    What do H and N refer to in the naming of flu viruses?

    <p>Hemagglutinins and Neuraminidase</p> Signup and view all the answers

    What is the main purpose of the immune system?

    <p>The immune system defends the body against foreign organisms and recognizes infections.</p> Signup and view all the answers

    What is the difference between innate and adaptive immunity?

    <p>Innate immunity is non-specific and present from birth, while adaptive immunity is specific and develops over time after exposure.</p> Signup and view all the answers

    Which of the following are components of innate (non-specific) immunity? (Select all that apply)

    <p>Physical barriers</p> Signup and view all the answers

    What bones make up the ossicles?

    <p>Malleus, incus, and stapes</p> Signup and view all the answers

    What is the function of outer hair cells in the cochlea?

    <p>Amplify soft sounds and dampen loud sounds</p> Signup and view all the answers

    What do inner hair cells do?

    <p>Transfer sound to the auditory nerve</p> Signup and view all the answers

    What is proprioception?

    <p>The sense of joint position and muscle length</p> Signup and view all the answers

    How many pairs of spinal nerves are there?

    <p>31</p> Signup and view all the answers

    What is the role of the Eustachian tube?

    <p>Equalize air pressure and drain mucus from the ear</p> Signup and view all the answers

    What does the Circle of Willis do?

    <p>Provides a backup blood supply to the brain</p> Signup and view all the answers

    Which factor can lead to increased intracranial pressure (ICP)?

    <p>Meningitis</p> Signup and view all the answers

    What type of information do afferent neurons carry?

    <p>Touch, skin temperature, muscle length, pain, and joint position</p> Signup and view all the answers

    What is the function of the blood-brain barrier?

    <p>Isolates neural tissue from the general circulation</p> Signup and view all the answers

    What function is associated with the frontal lobe?

    <p>Reasoning and problem solving</p> Signup and view all the answers

    What are the parts of a generalised neuron?

    <p>Cell body, dendrites, axons, axon terminal, myelin sheath</p> Signup and view all the answers

    Which part of a neuron is responsible for receiving information?

    <p>Dendrites</p> Signup and view all the answers

    What role do myelin sheaths play in neurons?

    <p>Increase the speed of electrical impulses</p> Signup and view all the answers

    What is a membrane potential?

    <p>A difference in charge between the inside and outside of cells</p> Signup and view all the answers

    What happens during depolarization in a neuron?

    <p>Sodium channels open, allowing sodium ions to enter the cell, making it positive on the inside.</p> Signup and view all the answers

    What is the function of glial cells?

    <p>Protect and support neurons</p> Signup and view all the answers

    The central nervous system (CNS) consists of the _____ and _____

    <p>brain, spinal cord</p> Signup and view all the answers

    What is a reflex arc?

    <p>A neural pathway that controls a reflex action</p> Signup and view all the answers

    Which cranial nerve is responsible for smell?

    <p>Olfactory nerve</p> Signup and view all the answers

    All neurons have a myelin sheath.

    <p>False</p> Signup and view all the answers

    The sympathetic nervous system is involved in 'rest and digest' activities.

    <p>False</p> Signup and view all the answers

    Describe one primitive reflex seen in infants.

    <p>The Moro reflex: startled look and arms spread apart when head is dropped lightly.</p> Signup and view all the answers

    Which medications can lead to potentially fatal arrhythmia when combined?

    <p>Digoxin</p> Signup and view all the answers

    Synergistic effect occurs when two drugs with similar effects are combined.

    <p>True</p> Signup and view all the answers

    What is the effect of combining Phenergan with a narcotic like Demerol?

    <p>Potentiating effect</p> Signup and view all the answers

    What is chemotherapy designed to destroy?

    <p>Fast-growing cancer cells</p> Signup and view all the answers

    Name one class of drugs that inhibits DNA/RNA synthesis in bacteria.

    <p>Quinolones</p> Signup and view all the answers

    What natural herb supplement may cause serious side effects when taken with certain antidepressants?

    <p>St John’s Wort</p> Signup and view all the answers

    How can drug resistance occur?

    <p>Through mutations and natural selection.</p> Signup and view all the answers

    Match the neurotransmitter to its role:

    <p>Acetylcholine = Learning, memory, muscle contraction Dopamine = Motivation, pleasure Serotonin = Mood regulation GABA = Inhibits brain activity</p> Signup and view all the answers

    What are the two major classes of analgesics?

    <p>Non-steroidal analgesics (NSAIDs) and Narcotic analgesics (opiates)</p> Signup and view all the answers

    What is a potential side effect of narcotic analgesics?

    <p>Seizures</p> Signup and view all the answers

    What is the amygdala responsible for?

    <p>Hub for fear and aggression, involved in emotional learning.</p> Signup and view all the answers

    People with damage to the amygdala can show fear and recognize it in others.

    <p>False</p> Signup and view all the answers

    What is the main function of the hippocampus?

    <p>Conversion of short-term to long-term memory.</p> Signup and view all the answers

    What are the two major branches of pharmacology?

    <p>Pharmacodynamics</p> Signup and view all the answers

    Define bioavailability.

    <p>The proportion of a drug that enters circulation when introduced into the body.</p> Signup and view all the answers

    What does the term 'therapeutic index' refer to?

    <p>Comparison of the amount of a therapeutic agent that causes the therapeutic effect to the amount that causes toxicity.</p> Signup and view all the answers

    What is an antagonist?

    <p>A drug that blocks a receptor from being activated by other substances.</p> Signup and view all the answers

    How does the selectivity of a drug for its receptor affect side effects?

    <p>Higher selectivity means the drug binds to fewer receptors, reducing the risk of side effects.</p> Signup and view all the answers

    The process by which drugs are broken down into inactive forms is called ______.

    <p>metabolism</p> Signup and view all the answers

    Which of the following factors can affect drug absorption?

    <p>All of the above</p> Signup and view all the answers

    What is meant by drug tolerance?

    <p>The body's adjustment to a drug over time, requiring higher doses to achieve the same effect.</p> Signup and view all the answers

    What is the role of basophils in the immune system?

    <p>Promotion of allergic responses and augmentation of anti-parasitic immunity.</p> Signup and view all the answers

    What do Pattern Recognition Receptors do?

    <p>They recognize a range of antigens and recruit immune responses when suspicious activity is identified.</p> Signup and view all the answers

    What is the function of interferons in the immune system?

    <p>They alert neighboring cells to produce antiviral proteins and combat bacterial and parasitic infections.</p> Signup and view all the answers

    List some functions of complement proteins in the blood.

    <p>Opsonization, chemotaxis, cell lysis, and clumping of antigen-bearing agents.</p> Signup and view all the answers

    Which pathways activate the complement system?

    <p>All of the above</p> Signup and view all the answers

    What are the components of acquired immunity?

    <p>Lymphocytes, including T cells and B cells.</p> Signup and view all the answers

    What type of cells are T cells and where are they produced?

    <p>Produced in the bone marrow</p> Signup and view all the answers

    What happens when tissue is damaged in the context of inflammation?

    <p>Localized redness, swelling, heat, and pain occur, along with increased capillary wall permeability.</p> Signup and view all the answers

    Name the two divisions of adaptive immunity.

    <p>Humoral immunity and cellular immunity.</p> Signup and view all the answers

    Describe how B cells are activated.

    <p>Through T cell-dependent activation or T cell-independent activation.</p> Signup and view all the answers

    What is the primary function of antibodies?

    <p>Inactivate antigens</p> Signup and view all the answers

    Which immunoglobulin is predominant in mucus, saliva, milk, and tears?

    <p>IgA</p> Signup and view all the answers

    IgE functions mainly in inflammatory responses and is effective against parasitic worms.

    <p>True</p> Signup and view all the answers

    Which of the following are classic signs of an opioid overdose? (Select all that apply)

    <p>Decreased respiratory rate</p> Signup and view all the answers

    What is the treatment for an opioid overdose?

    <p>Opioid antagonist</p> Signup and view all the answers

    What is tolerance in relation to drug use?

    <p>Tolerance is the body's state of reduced sensitivity to a drug when it is given in regular doses.</p> Signup and view all the answers

    What is dependence in relation to drug use?

    <p>Dependence is the physiological or psychological adaptation of the body to the presence of a drug.</p> Signup and view all the answers

    What does reuptake refer to in neurotransmission?

    <p>Reuptake refers to the process where neurotransmitters in the synaptic cleft re-enter the presynaptic neuron through channels in the membrane.</p> Signup and view all the answers

    Which type of microorganism is unicellular and has a nucleus?

    <p>Protozoa</p> Signup and view all the answers

    What structure do Gram-positive bacteria primarily possess?

    <p>Thick peptidoglycan layer</p> Signup and view all the answers

    All bacteria reproduce by _____ fission.

    <p>binary</p> Signup and view all the answers

    What are the four phases of bacterial growth?

    <p>Lag, exponential, stationary, and decline.</p> Signup and view all the answers

    Which immune response is non-specific?

    <p>Innate response</p> Signup and view all the answers

    What is the main purpose of the immune system?

    <p>To defend the body against foreign organisms and infections.</p> Signup and view all the answers

    Define phagocytosis.

    <p>Phagocytosis is the process by which certain cells (phagocytes) engulf and digest foreign particles or pathogens.</p> Signup and view all the answers

    What do H and N represent in HN naming of flu viruses?

    <p>Haemagglutinins and Neuraminidase</p> Signup and view all the answers

    Name the parts of a generalised neuron.

    <p>Cell body, dendrites, axons, axon terminal, myelin sheath</p> Signup and view all the answers

    Which of the following is an input area of a neuron?

    <p>Dendrites</p> Signup and view all the answers

    What are glial cells?

    <p>Cells that protect and support neurons</p> Signup and view all the answers

    The process of creating a difference in charge across a membrane is known as ______.

    <p>membrane potential</p> Signup and view all the answers

    What occurs during depolarisation in a neuron?

    <p>Sodium ions enter the cell, making it positive inside.</p> Signup and view all the answers

    Explain what repolarisation is.

    <p>Potassium ions move out of the cell, returning to a negative internal charge.</p> Signup and view all the answers

    Which division of the nervous system controls voluntary muscle movements?

    <p>Somatic nervous system</p> Signup and view all the answers

    What is a reflex arc?

    <p>The neural pathway that mediates a reflex action.</p> Signup and view all the answers

    Myelin increases the speed of conduction in axons.

    <p>True</p> Signup and view all the answers

    Which cranial nerve is responsible for smell?

    <p>Olfactory nerve</p> Signup and view all the answers

    What is the function of the optic nerve?

    <p>Vision</p> Signup and view all the answers

    Taste receptors are located on the ______.

    <p>tongue</p> Signup and view all the answers

    What is a synergistic effect in pharmacology?

    <p>When two drugs increase each other's effects</p> Signup and view all the answers

    Potentiating effect occurs when one drug enhances the effect of another without having an effect of its own.

    <p>True</p> Signup and view all the answers

    What can happen when digoxin and verapamil are combined?

    <p>Toxic levels and potentially fatal arrhythmia</p> Signup and view all the answers

    How does chemotherapy affect fast-growing cells?

    <p>It destroys fast-growing cancer cells but also affects normal fast-growing cells.</p> Signup and view all the answers

    Which of these drugs inhibit DNA/RNA synthesis?

    <p>Quinolones</p> Signup and view all the answers

    What causes drug resistance?

    <p>Mutations and natural selection</p> Signup and view all the answers

    Too little serotonin is associated with _________ and some anxiety disorders.

    <p>depression</p> Signup and view all the answers

    What are common side effects of narcotic analgesics?

    <p>All of the above</p> Signup and view all the answers

    What neurotransmitter is important for voluntary movement and learning?

    <p>Acetylcholine</p> Signup and view all the answers

    What action do opioids have on pain signals?

    <p>They dampen down pain signals.</p> Signup and view all the answers

    What are the three hearing bones in the ossicles?

    <p>Malleus, incus, stapes</p> Signup and view all the answers

    What is the main function of the cochlea?

    <p>To contain hearing receptors and transmit sound to the auditory nerve.</p> Signup and view all the answers

    Outer hair cells amplify sounds, while inner hair cells transfer sound to the auditory nerve.

    <p>True</p> Signup and view all the answers

    Which receptors are activated when the head moves?

    <p>Hearing receptors</p> Signup and view all the answers

    What is the normal state of the Eustachian tube?

    <p>Normally closed</p> Signup and view all the answers

    What information do afferent neurons in spinal nerves carry?

    <p>Touch, skin temperature, muscle length, pain, joint position.</p> Signup and view all the answers

    How many pairs of spinal nerves are there?

    <p>31 pairs</p> Signup and view all the answers

    What does the acronym '8 Crabs, 12 Turtles, 5 Lizards & 5 Snakes' refer to?

    <p>The number of pairs of cervical, thoracic, lumbar, sacral, and coccygeal spinal nerves.</p> Signup and view all the answers

    Which type of injury is indicated by hyperreflexia?

    <p>Upper motor neuron damage</p> Signup and view all the answers

    What is the primary function of the spinothalamic tract?

    <p>Carries sensory impulses related to pain, temperature, and crude touch to the brain.</p> Signup and view all the answers

    At what point does decussation occur for the spinothalamic tract?

    <p>Immediately in the spinal cord</p> Signup and view all the answers

    The Circle of Willis helps protect the brain from ischaemia.

    <p>True</p> Signup and view all the answers

    What are the roles of the cranium, meninges, cerebrospinal fluid, and blood-brain barrier?

    <p>Protection of the brain from injury, maintaining a constant environment, and cushioning.</p> Signup and view all the answers

    What factors can lead to an increase in intracranial pressure (ICP)?

    <p>Inflammation, hemorrhage, mass (tumor), hypertension, increased CSF pressure.</p> Signup and view all the answers

    What does hyper-osmolarity do to the blood-brain barrier?

    <p>It can compromise the barrier, allowing substances to cross that normally wouldn't.</p> Signup and view all the answers

    What is the role of the amygdala?

    <p>Hub for fear and aggression, involved in emotional learning.</p> Signup and view all the answers

    What are the consequences of damage to the amygdala?

    <p>Inability to show or recognize fear, inability to recognize risky behaviors, and avoidance of eye contact.</p> Signup and view all the answers

    What is the primary function of the hippocampus?

    <p>Conversion of short-term to long-term memory.</p> Signup and view all the answers

    Which area of the brain is primarily responsible for speech formulation?

    <p>Broca's area</p> Signup and view all the answers

    What are the two major branches of pharmacology?

    <p>Pharmacodynamics and Pharmacokinetics</p> Signup and view all the answers

    Define pharmacodynamics.

    <p>The biochemical and physiological effects of drugs on the body.</p> Signup and view all the answers

    Define pharmacokinetics.

    <p>The absorption, distribution, metabolism, and excretion of drugs.</p> Signup and view all the answers

    What is bioavailability?

    <p>The proportion of a drug that enters circulation</p> Signup and view all the answers

    What defines a drug receptor agonist?

    <p>A drug that binds to a receptor and activates it.</p> Signup and view all the answers

    What defines a drug receptor antagonist?

    <p>A drug that binds to a receptor but does not activate it, blocking other substances.</p> Signup and view all the answers

    What is an example of a drug that acts as an agonist?

    <p>Morphine</p> Signup and view all the answers

    What can happen if two drugs are metabolized by the same enzyme?

    <p>They will compete with each other, slowing down metabolism</p> Signup and view all the answers

    Describe the impact of pharmacokinetics on drug effectiveness.

    <p>Determines the duration, concentration, and bioavailability of a drug.</p> Signup and view all the answers

    What is the function of basophils?

    <p>Promotion of allergic responses and augmentation of anti-parasitic immunity.</p> Signup and view all the answers

    What do Pattern Recognition Receptors recognize?

    <p>A whole range of antigens.</p> Signup and view all the answers

    How do Toll-Like Receptors function?

    <p>They act like mines that release cytokines when pathogens touch them.</p> Signup and view all the answers

    What is the role of Interferons?

    <p>To alert neighboring cells to produce antiviral proteins.</p> Signup and view all the answers

    What are the main functions of Complement proteins?

    <p>Opsonization, chemotaxis, cell lysis, and clumping of antigen-bearing agents.</p> Signup and view all the answers

    Which pathway of Complement activation is triggered by antibody binding?

    <p>Classical pathway</p> Signup and view all the answers

    T cells are produced in the _____ and mature in the _____

    <p>bone marrow; thymus</p> Signup and view all the answers

    What are the four types of T cells?

    <p>Th, Tc, Ts, Tm.</p> Signup and view all the answers

    What do B cells produce?

    <p>Antibodies.</p> Signup and view all the answers

    How is inflammation characterized?

    <p>Localized redness, swelling, heat, and pain.</p> Signup and view all the answers

    What are the two divisions of adaptive immunity?

    <p>Humoral immunity and cellular immunity.</p> Signup and view all the answers

    What is one way B cells are activated?

    <p>T cell-dependent activation.</p> Signup and view all the answers

    Which immunoglobulin is predominant in saliva and tears?

    <p>IgA</p> Signup and view all the answers

    Which immunoglobulin is involved in allergic responses?

    <p>IgE</p> Signup and view all the answers

    Which of the following are classic signs of an opioid overdose? (Select all that apply)

    <p>Pinpoint pupils</p> Signup and view all the answers

    What is the purpose of using an opioid antagonist in an overdose?

    <p>To counteract the effects of opioids and restore consciousness.</p> Signup and view all the answers

    Tolerance leads to the body’s state of reduced sensitivity to a drug when it is given in regular doses, requiring larger doses to produce the same ___ effect.

    <p>therapeutic</p> Signup and view all the answers

    What is the definition of dependence?

    <p>The physiological or psychological adaptation of the body to the presence of a drug.</p> Signup and view all the answers

    How are neurotransmitters removed from the synaptic space after release?

    <p>Through reuptake into the presynaptic neuron.</p> Signup and view all the answers

    Which of the following is a type of microorganism that can cause disease in humans? (Select all that apply)

    <p>Viruses</p> Signup and view all the answers

    Who first discovered microorganisms?

    <p>Anton Van Leeuwenhoek</p> Signup and view all the answers

    Gram-positive bacteria have a thin peptidoglycan layer.

    <p>False</p> Signup and view all the answers

    What is the main role of the immune system?

    <p>To defend the body against foreign organisms and pathogens.</p> Signup and view all the answers

    Match the following types of immunity with their characteristics:

    <p>Innate immunity = Non-specific response to pathogens Adaptive immunity = Specific response to particular antigens Passive immunity = Immunity obtained from another individual Active immunity = Immunity developed after exposure to an antigen</p> Signup and view all the answers

    Natural killer cells are effective against ___ cells and intracellular pathogens.

    <p>cancer</p> Signup and view all the answers

    Study Notes

    Spinal Nerves

    • 31 pairs of spinal nerves: 8 cervical, 12 thoracic, 5 lumbar, 5 sacral, and 1 coccygeal
    • Nerve Plexus: Network of intersecting nerves
    • Cervical nerves exit above their corresponding vertebrae
    • Thoracic, lumbar, and sacral nerves exit below their corresponding vertebrae
    • Dermatomes: Relationship between spinal nerve and skin, supplied by sensory nerve fibers
    • Myotomes: Relationship between spinal nerve and muscle, supplied by motor nerve fibers
    • Damage to a particular spinal nerve will affect a predictable area of the body based on its vertebral level
    • Shingles: Virus travels down axons and causes painful skin eruption
    • Referred pain: Pain is located away from the organ involved due to corresponding sensory nerves

    Spinal Cord Lesions

    • Posterior (Dorsal) side of spinal cord: Where dorsal root sensory neurons enter
    • Anterior (Ventral) side of spinal cord: Where ventral root motor neurons exit
    • White matter: Sensory information travels up the spinal cord to the brain
    • Grey matter: Motor information travels from the brain down the spinal cord
    • Higher up the spinal cord the injury occurs: Greater dysfunction occurs
    • Complete Spinal Cord Injury: No movement or sensation at or below the level of injury
    • Incomplete Spinal Cord Injury: Some movement or sensation at or below the level of injury
    • No reflexes: Damage to a lower spinal nerve
    • Hyperreflexia: Upper motor neuron damage, lack of inhibitory reflex
    • Injury at C4: Diaphragm affected and could compromise breathing

    Brain Blood Supply

    • Circle of Willis: Backup system for the brain in case of an internal carotid or vertebral artery blockage
    • Brain constantly needs blood: Little change in blood flow amount occurs

    Brain Protection

    • Cranium: Hard bony plates that protect the brain from hard blows
    • Meninges: Connective tissue that protects the brain and spinal cord
      • Epidural Space: Space above dura mater
      • Dura Mater: Outermost layer
      • Subdural Space: Abnormal space below dura mater
      • Arachnoid Mater: Spider web-like appearance
      • Subarachnoid Space: Space between arachnoid mater and pia mater, contains cerebrospinal fluid
      • Pia Mater: Innermost delicate layer, holds blood vessels tightly
    • Cerebrospinal Fluid: Cushions and supports the brain and spinal cord, transports nutrients, chemical messages, and waste products
    • Blood-Brain Barrier: Neural tissue isolated from the general circulation by tightly connected endothelial cells and tight junctions
      • Protects the brain from foreign substances
      • Maintains a constant environment for the brain
      • Glial cells (Astrocytes) help form the BBB
    • Substances that easily cross the BBB:
      • Lipid-soluble compounds (e.g., carbon dioxide, oxygen, ammonia, nicotine, anaesthetics) and lipids (e.g., steroids or prostaglandins or small alcohols)
      • Some electrolytes (not K+)
      • Essential amino acids
      • Glucose
      • Caffeine
      • Some antibiotics
      • Water and ions
    • Substances that cannot easily cross the BBB:
      • Proteins
      • Protein-bound substances
      • Strongly hydrophilic (water soluble) substances
      • Neurotransmitters
      • Morphine
    • BBB can be compromised by:
      • Hypertension
      • Hyper-osmolarity
      • Radiation
      • Infection
      • Trauma
      • Ischaemia
      • Inflammation
      • Pressure
    • BBB not fully formed at birth
    • Alzheimer's involves defective microglia and/or a defective BBB

    Intracranial Pressure (ICP)

    • ICP: Pressure inside the cranium
    • Factors that increase ICP:
      • Inflammation (e.g., meningitis, encephalitis)
      • Haemorrhage (e.g., subdural haematoma)
      • Mass (e.g., tumour)
      • Hypertension
      • Increased CSF pressure
      • Stroke
      • Aneurysm
      • Status epilepticus
      • Space-occupying lesion
    • Classic Signs of Raised ICP:
      • Deep, irregular respiration
      • Widening pulse pressure
      • Bradycardia

    Major Brain Areas

    • Brainstem: Connects spinal cord to cerebrum, important for vital functions
      • Midbrain: Temperature regulation, vision, hearing, sleep/wake, arousal
      • Pons: Arousal/level of alertness, relays sensory information between cerebrum and cerebellum
      • Medulla: Controls basic survival functions (respirations, BP, pulse, digestion, swallowing, sneezing)
    • Cerebellum: Coordinates and controls voluntary movements, postural adjustment, planning rapid movements, learning of movement sequences
    • Cerebrum: Largest part of the brain, divided into four lobes
      • Frontal Lobe: Reasoning, fluency and construction of speech, movement, emotions, personality, and problem solving
      • Parietal Lobe: Movement, orientation, recognition, perception of touch stimuli and proprioception
      • Occipital Lobe: Processing of visual stimuli
      • Temporal Lobe: Perception and recognition of auditory stimuli, short-term memory, language, and comprehension
    • Limbic System: Emotional brain, responsible for emotional memory and learning, recognition of emotions, emotional intelligence, and autonomic and endocrine responses to emotional states
      • Cingulate cortex, Hippocampus, Amygdala, and Hypothalamus
      • Amygdala: Hub for fear and aggression, involved in emotional learning, allows recognition of fear, strongly activated during exposure to aversive stimuli
        • People with Amygdala damage: Cannot show or recognize fear, unable to recognize and weigh up risky behaviors, avoid eye contact, stand closer to others during contact,
      • Hippocampus: Hub for memory, conversion of short-term to long-term memory, memory for place

    Brain Function: Complexity and Evolution

    • Brainstem: Simplest part, evolved 500mya, controls vital functions
    • Cerebellum: Developed a few hundred mya, responsible for movement coordination
    • Limbic system: Evolved 250mya, responsible for emotions
    • Cerebral hemispheres: Developed 200mya, responsible for higher-order processes like learning, reasoning, and language
    • Cerebral lateralization: Hemisphere containing language and speech areas is the dominant hemisphere (97% of people are left-brain dominant)

    Stroke: Location and Impact

    • Right cerebral hemisphere stroke: Left side paralysis, difficult reasoning/problem solving
    • Left cerebral hemisphere stroke: Right side paralysis, may disrupt the ability to speak

    Pharmacology

    • Pharmacology is the study of the origins, nature, chemistry, effect and use of drugs.
    • The two major branches of pharmacology are pharmacodynamics and pharmacokinetics.
    • Pharmacodynamics is the biochemical and physiological effects of drugs on the body, "what the drug does to the body"
    • Pharmacokinetics is the absorption, distribution, metabolism and excretion of the drug, "what the body does to the drug"

    Drug Naming

    • Drugs can be named using Generic Name, Trade Name, and Chemical Name.
    • The Generic Name is the official, non-proprietary name of a drug that is used by regulatory bodies and healthcare professionals, such as diazepam, ibuprofen, morphine, etc.
    • The Trade Name is the commercial brand name given by the manufacturer, such as Valium, Advil, and Morphine Sulfate.
    • The Chemical Name is the systematic name of the molecular structure of the substance.

    Places Drugs Act

    • Most drugs bind chemically to a specific site called a target to produce their action.

    • Drugs can act on receptors for endogenous substances like hormones, neurotransmitters, and growth factors.

      • Agonist: A drug that binds to a receptor and activates cellular activity, such as opioid analgesics which stimulate opioid receptors.
      • Antagonist: A drug that binds to a receptor and blocks other substances from binding to and activating it, such as beta blockers which block noradrenaline (beta) receptors.

    • Drugs can act on transport molecules, such as the serotonin transporter which is inhibited by SSRIs resulting in an increase in free serotonin.

    • Drugs can act on ion channels, such as benzodiazepines that bind to GABA-A receptors causing an inhibitory action, leading to sedation.

    • Drugs can act on enzymes.

      • Inhibition: Some drugs inhibit enzymes to block their activity, such as NSAIDs which inhibit the enzyme cyclooxygenase to reduce inflammation and pain, or ACE inhibitors which inhibit angiotensin converting enzyme resulting in lower blood pressure.
      • False Substrate: Some drugs act as false substrates causing the enzyme to produce a wrong product.

    Key Pharmacological Terms

    • Bioavailability: The proportion of a drug administered that enters the circulation and has an active effect.
    • Therapeutic Index: The comparison of the amount of a therapeutic agent that causes the therapeutic effect to the amount that causes toxicity.
    • Adverse Effect: A harmful and undesired effect of a medication
    • Therapeutic Effect: The desirable and beneficial results of a medical treatment, often called the intended effect.
    • Contraindication: A reason that makes it inadvisable to prescribe a particular drug, procedure, or treatment.

    Drug Receptor Properties

    • Affinity: The tendency for a drug to bind with its receptor. A drug with high affinity will readily bind to its receptors.
    • Efficacy: The ability of a drug to produce a desired or intended result.
    • Potency: The amount of a drug needed to produce a particular size of effect. This depends on the drug's affinity and efficacy.
    • Selectivity: The degree to which a drug will bind to certain receptors over others, determined by the difference in affinity.

    Pharmacokinetic Processes

    • Absorption: The movement of the drug from its administration site into the bloodstream. Factors that affect absorption include route of administration, physiological state, chemical properties of the drug, and gastric emptying rate..
    • Distribution: The spread of a drug throughout the various compartments of the body. Factors that affect distribution include molecular size, solubility, body composition, blood flow to the targeted tissue, and removal rate by the liver.
    • Metabolism: The breakdown of drugs into inactive forms and conversion into more water-soluble forms ready for excretion. Factors affecting metabolism include the efficiency of the liver and kidneys, age, diet, hormone balance, physiological state, and drug interactions.
      • Enzyme Inhibition: When two drugs are metabolized by the same enzyme, they compete with each other.
      • Enzyme Induction: Some drugs increase the activity of enzymes, leading to faster metabolism of other drugs.
    • Excretion: The removal of drug metabolites from the body. Factors effecting excretion include the filtration in the kidneys, rate of metabolism, age, blood flow to the kidneys, molecular size of the drug, and binding characteristics of the drug.

    Drug Interactions

    • Drug interactions can affect absorption, distribution, metabolism, and excretion, leading to various outcomes.
      • Potentiation: One drug enhances the effect of another drug (E.g. Phenergan and Demerol).
      • Synergistic Effect: Two drugs with similar effects can have an intensified effect when combined (E.g. Diazepam and Alcohol).
      • Antagonistic Effect: Two drugs have opposite effects, counteracting each other (Not given in example).

    Chemotherapy: Basic Principles

    • Chemotherapy is a chemical treatment designed to destroy fast-growing cancer cells.
    • Chemotherapy drugs often do not differentiate between normal and cancerous cells, which leads to side effects such as hair loss, reduced immunity, etc.
    • Chemotherapy exploits differences between normal and cancer cells.

    Chemotherapy Targets

    • Antibacterial Drugs: Exploit difference in cell wall, DNA/RNA synthesis, ribosomes, cell membrane, and metabolism between bacteria and human cells.
    • Antifungal Drugs: Exploit differences in cell walls and membranes between fungi and human cells.
    • Antiviral Drugs: Exploit differences in viral attachment, uncoating, replication, assembly, and budding.
    • Cytotoxic Drugs: Exploit differences between tumor cells and normal cells.

    Drug Resistance

    • Pathogens can develop resistance to antimicrobial and anticancer drugs through mutations, which can be advantageous, deleterious, or neutral.
    • Advantageous mutations that enhance pathogen survival against drugs are passed on to future generations, leading to drug resistance.
    • Overuse or misuse of antibiotics can increase the selection pressure for resistant bacteria.
    • Some examples of bacterial resistance include bacterial chromosomal mutations, the synthesis of enzymes that alter drug structure, the prevention of drug entry into the cell, and the alteration of drug receptors on cell targets.

    Neurotransmitters and Disease

    • Acetylcholine: Involved in voluntary movement, learning, memory, anger/aggression, sexuality, and sleep.
      • Excess acetylcholine is associated with depression.
      • Deficiency in the hippocampus has been linked to dementia.
    • Noradrenaline/Norepinephrine: Important for attentiveness, emotions, sleeping, dreaming, and learning. Plays a role in 'fight or flight' responses.
      • Involved in mood disorders, such as manic depression.
    • Adrenaline/Epinephrine: Causes vasodilation, bronchodilation, increases blood glucose and fatty acids, and contributes to 'fight or flight' responses.
      • Deficiency has been associated with depression.
    • Dopamine: Regulates motor behaviour, pleasure, motivation, emotional arousal, and dependency.
      • Excess dopamine is linked to schizophrenia.
      • Deficiency is associated with some forms of depression and the muscular rigidity and tremors found in Parkinson's disease.
    • Serotonin: Regulates sleep, appetite, memory, learning, temperature, mood, behaviour, muscle contraction, and CNS and endocrine system functioning.
      • Deficiency is associated with depression, anxiety disorders, and OCD.
    • GABA: Inhibits brain activity and sedates the nervous system.
      • Deficiency is linked to anxiety and anxiety disorders.
    • Endorphins: Link pain with emotional centres of the brain and can produce analgesia.
      • Involved in pleasure during exercise, orgasm, love, and eating spicy food.
      • Contribute to an overall feeling of well-being.

    Antidepressants

    • Antidepressants work by increasing the amount of certain neurotransmitters in the brain by inhibiting their reuptake.
    • The six main families of antidepressants, from oldest to newest, are:
      • Monoamine oxidase inhibitors (MAOIs)
      • Tricyclics
      • Selective serotonin reuptake inhibitors (SSRIs)
      • Noradrenaline-serotonin reuptake inhibitors (NSRIs)
      • Selective noradrenaline reuptake inhibitors (SNRIs)
      • Noradrenaline-dopamine reuptake inhibitors (NDRIs)
    • Newer antidepressants are generally more selective in their mode of action, leading to fewer side effects and longer-term use.

    Treatment of Mania

    • Lithium is a mood-stabilizing drug that can be used to treat mania.
    • It alters the function of several neurotransmitters.
    • Lithium has a narrow therapeutic index and requires blood level monitoring.
    • Toxic doses can cause confusion, seizures, and coma.
    • Common side effects include muscle tremor, nausea, vomiting, diarrhoea, polydipsia, thirst, loss of appetite, and kidney failure.
    • If lithium fails, other drugs such as anticonvulsants, sedatives, or antipsychotics may be used.

    Autonomic Neurotransmitters and Receptors

    • Sympathetic division (fight or flight): relies on noradrenaline and adrenaline.
    • Parasympathetic division (rest and restore): relies on acetylcholine.
    • Adrenoceptors (adrenergic receptors): activated by noradrenaline.
      • α1: Found in blood vessels, causes vasoconstriction.
      • α2: Found in the brain, inhibits noradrenaline release.
      • β1: Found in the heart, increases heart rate and strength of beat.
      • β2: Found in bronchioles and blood vessels, causes bronchodilation and vasodilation.
      • β3: Found in fat cells, causes mobilization of fat.
    • Cholinergic receptors: Activated by acetylcholine.
      • Nicotinic: Found on skeletal muscle, produces contraction.
      • Muscarinic: Found in the brain, organs, and glands, produces parasympathetic responses.

    Clinical Uses of Autonomic Drugs

    • Antihypertensives (beta-blockers, β antagonists): Treat hypertension and reduce the risk of cardiac arrhythmia after a myocardial infarction.
    • β2 agonists: Treat asthma (e.g., salbutamol).
    • Beta-blockers (β antagonists): Treat glaucoma (increased pressure in the eye).
    • Muscarinic antagonists: Treat nasal congestion, diarrhoea, and motion sickness.
    • β1 agonists (adrenaline): Used in emergency resuscitation (cardiac arrest) and anaphylaxis.

    Analgesics

    • Non-steroidal analgesics (NSAIDs): Block the production of pain stimuli, such as histamine, by inhibiting the enzyme cyclooxygenase (COX). This reduces prostaglandin production.
    • Narcotic analgesics (opiates): Dampen down the emotional response to pain and activate an inhibitory reaction in the brain. They are agonists at our endogenous opioid receptors.
    • Examples of NSAIDs: Aspirin, ibuprofen, celecoxib.
    • Examples of narcotics: Morphine, codeine, methadone, pethidine, fentanyl.

    Side Effects of Analgesics

    • NSAIDs:
      • Stomach upset, nausea, vomiting, ulcers.
      • Increased risk of bleeding.
      • Kidney problems.
    • Narcotics:
      • Constipation.
      • Light-headedness, dizziness, drowsiness.
      • Stomach upset, nausea, vomiting.
      • Respiratory depression.
      • Irregular heartbeat.
      • Anxiety.
      • Tremors.
      • Appetite suppression.
      • Tolerance and dependence.
      • Itching.

    Opioid Overdose

    • Classic signs: Pinpoint pupils, decreased respiratory rate (sometimes apnoea), coma, hypotension, convulsions.
    • Treatment: Use an opioid antagonist (antidote), such as naloxone or naltrexone.

    Tolerance and Dependence

    • Tolerance: Reduced sensitivity to a drug when given in regular doses, requiring higher doses for the same effect.
    • Dependence: The body becomes physiologically or psychologically adapted to the presence of a drug. Withdrawal occurs upon cessation or antagonism.

    Removal of Neurotransmitters from the Synaptic Space

    • Neurotransmitters are removed from the synaptic space after release by reuptake into the presynaptic neuron.
    • Agonist drugs: Enhance the effects of neurotransmitters by binding to receptors or by blocking reuptake.
    • Antagonist drugs: Block receptors or inactive them, reducing neurotransmitter effects.

    Microorganisms

    • Microorganisms (microbes): Microscopic organisms, including single-celled or multicellular organisms.
    • Key types of microorganisms that cause disease in humans:
      • Fungi (eukaryotic with rigid cell walls)
      • Protozoa (unicellular eukaryotes with no nucleus)
      • Bacteria (unicellular prokaryotes with no nucleus)
      • Viruses (contain genetic material but no nucleus, organelles, or cytoplasm)
      • Parasites (endoparasites live inside the body, ectoparasites live on the surface)

    Key Fungi, Protozoa, and Parasites

    • Fungi:
      • Moulds: Food spoilage and antibiotics (e.g., Penicillium)
      • Types of fungal infections: superficial mycoses, cutaneous mycoses, subcutaneous mycoses, systemic mycoses (e.g., tinea versicolor, Athlete’s foot, ring worm, mycetoma, Candida albicans, Histoplasmosis, Pneumocystis pneumonia).
    • Protozoa:
      • Entamoeba histolytica: Major cause of dysentery.
      • Giardia Intestinalis: Attaches to the small intestine and causes diarrhoea, malaise, and gas.
      • Malaria: Caused by Plasmodium parasites transmitted through mosquito saliva, infecting the liver and red blood cells.
    • Parasites:
      • Endoparasites (Helminth Worms): Flatworms (flukes and tapeworms) and Nematodes (roundworms).
      • Ectoparasites: Fleas, lice (Pediculus humanus), mites (Sarcoptes scabei causing scabies).

    Bacterial Structure and Physiology

    • Common features:

      • Cell membrane (phospholipid bilayer)
      • Cell wall (composed primarily of peptidoglycan)

    • Gram-positive:

      • Thick peptidoglycan layer on the outside of the cell wall.
      • Stains purple.

    • Gram-negative:

      • Thin peptidoglycan layer covered by an outer membrane.
      • Contains lipopolysaccharide (LPS), which is toxic during infections.
      • Stains pink.### Bacterial Structure

    • Some bacteria have a glycocalyx, a slime layer that protects the bacterium

    • Some bacteria have flagella, used for motility

    • Pili are used for conjugation and transfer of genetic material

    • Fimbriae are used for attachment to surfaces, including host tissue

    • The cell wall of bacteria determines its shape and staining properties

    • The cell wall protects the bacteria from osmotic lysis and some toxic substances

    • The cell wall contains components that contribute to pathogenicity

    • Some bacteria produce endotoxins, which are part of the cell wall and released upon bacterial death

    • Endotoxins are usually formed by Gram-negative bacteria

    • Endotoxins can cause fever in the host and are moderately toxic

    • Some bacteria produce exotoxins, which are excreted by the bacterium or released when the cell lyses

    • Exotoxins can be formed by both Gram-positive and Gram-negative bacteria

    • Exotoxins are highly toxic and can destroy cells and disrupt normal metabolism

    Bacterial Growth

    • Bacteria reproduce through binary fission
    • The generation time of bacteria can be as short as 20 minutes or as long as hours
    • The growth of bacteria can be divided into four phases: lag, exponential, stationary, and decline
    • In the lag phase, bacteria assess the environment before starting to replicate
    • The exponential phase is characterized by rapid replication, leading to a large increase in bacterial numbers
    • The stationary phase occurs when nutrients or space become limited
    • In the decline phase, the environment can no longer support the bacteria, and some begin to die
    • Pure cultures are often used to increase the number of bacteria in a sample
    • Agar plates are used to feed bacteria from a swab overnight

    Identification Methods

    • Gram stain is used to differentiate bacteria based on their cell wall structure
    • Gram-positive bacteria stain purple, while Gram-negative bacteria stain pink
    • Other stains are used to identify flagella, capsules, and other structures
    • Bacteria can be identified by their cell morphology, colony morphology, and growth requirements (aerobic, anaerobic, or both)

    Serological Tests

    • Serological tests involve the detection of specific antibodies

    Molecular Techniques

    • Polymerase Chain Reaction (PCR) is a molecular technique used to detect specific nucleic acid sequences

    Biochemical Tests

    • Biochemical tests are used to identify bacteria based on their enzyme production or sugar metabolism

    Viral Structure

    • Viruses are composed of a protein shell (capsid) surrounding viral DNA or RNA
    • The capsid is responsible for the virus's antigenic structure
    • Enveloped viruses have an outer coat (envelope) derived from the host cell's lipid bilayer
    • Proteins protruding from the envelope are called peplomers and are involved in attaching the virus to host cells

    Viral Replication

    • Viruses do not have a mechanism to correct mutations, leading to the emergence of different strains
    • Viral infection and replication occur in six main stages:
      • Adsorption: the virus binds to the host cell
      • Penetration: the virus injects its genome into the host cell
      • Viral Genome Replication: the viral genome replicates using the host's cellular machinery
      • Assembly: viral components and enzymes are produced and begin to assemble
      • Maturation: viral components assemble and the virus fully develops
      • Release: newly produced viruses are expelled from the host cell

    Flu Virus Naming

    • Flu viruses are named according to their haemagglutinins (H) and neuraminidase (N)
    • These proteins are spikes and enzymes found on the viral surface
    • H1N1 is the Spanish flu that killed up to 100 million people worldwide
    • H2N2 is the Asian flu that resulted in 1-4 million deaths
    • H1N1 is the swine flu that was declared a pandemic in 2009 and had a low mortality rate
    • H5N1 is the bird flu that caused around 240 human deaths and led to the killing or culling of millions of birds

    Immune System

    • The immune system is a dynamic network that defends the body against foreign organisms
    • The immune system recognizes infection and initiates protective countermeasures
    • The lymphatic system is a network of vessels that collects and filters interstitial fluid
    • Lymph nodes are part of the lymphatic system and house and transport white blood cells
    • The lymphatic system helps remove foreign materials from the body
    • Lymph nodes become swollen and painful during infection

    Innate Immunity

    • Innate immunity is non-specific and present from birth
    • Innate immunity includes physical barriers, chemicals, phagocytosis, natural killer cells, inflammation, and fever
    • Physical barriers include skin, mucous membranes, and cilia
    • Chemicals include enzymes, pH extremes, high salt concentrations, interferons, complement, and lysozyme
    • Phagocytosis is carried out by neutrophils, dendritic cells, eosinophils, monocytes, and macrophages
    • NK cells circulate in the blood and check MHC I tags on cells, targeting foreign material
    • Inflammation is triggered by damage or death to tissue and mobilizes local and systemic defenses
    • Fever is the maintenance of body temperature above 37.2˚C

    Leukocytes

    • Neutrophils are the most abundant leukocytes and are the first line of defense against bacteria
    • Eosinophils function in inflammatory and allergic responses and phagocytose antibody-coated parasites
    • Basophils release histamine and heparin during inflammatory and allergic responses
    • Monocytes circulate in the blood and differentiate into macrophages and dendritic cells
    • Macrophages phagocytose pathogens and activate bacterial mechanisms
    • Dendritic cells phagocytose pathogens and present them to T cells
    • NK cells are lymphocytes that target cells without MHC I tags

    Pattern Recognition Receptors

    • Pattern recognition receptors recognize a range of antigens and recruit an immune response
    • Toll-like receptors act as sensors and release cytokines when pathogens are detected

    Interferons

    • Interferons are cytokines released by host cells infected with pathogens
    • Interferons alert neighboring cells to produce antiviral proteins
    • Interferons can combat bacterial and parasitic infections, inhibit cell division, and promote or impede cell differentiation

    Complement

    • Complement is a protein found in the blood that amplifies the immune response
    • Complement functions include opsonization, chemotaxis, cell lysis, and clumping of antigen-bearing agents
    • Complement can be activated by the classical, alternative, or lectin pathway
    • The classical pathway is triggered by antibody bound to the surface of a pathogen
    • The alternative pathway is activated by the direct recognition of certain microbial structures
    • The lectin pathway is activated by the binding of mannose-binding lectin to proteins on microbial glycoproteins and glycolipids

    Adaptive Immunity

    • Adaptive immunity is specific and builds up over time after exposure to an antigen.
    • Adaptive immunity is slower to respond than innate immunity but has memory of antigens, allowing for a faster and greater response upon subsequent exposure
    • Adaptive immunity is systemic, not restricted to the site of infection
    • Adaptive immunity includes lymphocytes, antibodies, and antigen-presenting cells
    • T cells are produced in the bone marrow and mature in the thymus
    • B cells are produced and mature in the bone marrow
    • Antibodies are glycoproteins that are specific to an antigen and work to inactivate that antigen

    Inflammation

    • Inflammation is a response to tissue damage or death
    • Inflammation causes redness, swelling, heat, and pain
    • Inflammation increases capillary wall permeability, allowing WBCs to leak out
    • Inflammation promotes macrophage activity
    • Macrophages secrete interleukins during inflammation
    • Interleukin-1 increases body temperature and causes drowsiness

    B cell Activation

    • B cells can be activated through T cell-dependent or T cell-independent pathways
    • In T cell-dependent activation, an antigen is presented to a T helper cell, which activates the B cell to differentiate into plasma cells and memory cells
    • Plasma cells produce antibodies specific to the antigen
    • In T cell-independent activation, B cells can attach directly to an epitope on an antigen and proceed to internalize and destroy it

    Antibody Types

    • IgM is the first antibody to appear after infection
    • IgG is the most abundant antibody, can easily leave the blood and enter tissue, and can cross the placenta
    • IgA is found in saliva, mucus, milk, and tears
    • IgE stimulates the release of histamine and is involved in allergic responses and anti-parasitic immunity
    • IgD is another antibody type

    Neuron Structure and Function

    • Neurons are the fundamental functional unit of the nervous system, transmitting electrochemical messages known as nerve impulses or action potentials.
    • Key components of a neuron include:
      • Cell body (soma): Contains the nucleus and produces proteins essential for neuronal function.
      • Dendrites (input): Highly branched projections that receive information from other neurons.
      • Axon (integration): A long nerve fiber responsible for propagating action potentials from the cell body to the axon terminal.
      • Axon terminal (output): Nerve endings forming synaptic contacts with other neurons or effector cells, containing neurotransmitters for communication.
      • Myelin sheath: An insulating cover that increases the speed of action potential transmission along the axon.
    • A single neuron integrates multiple inputs (excitatory or inhibitory) to generate a single output response, enabling rapid processing of large amounts of information.

    Glial Cells

    • Glial cells are specialized cells that support and protect neurons.
    • Four major types of glial cells:
      • Astrocytes: Provide structural support, form scar tissue, transport substances between blood vessels and neurons, communicate with each other and neurons, and regulate ion and neurotransmitter balance.
      • Oligodendrocytes: Form myelin sheaths in the brain and spinal cord, producing nerve growth factors.
      • Microglia: Provide structural support and phagocytosis (immune defense).
      • Ependymal cells: Form a porous layer facilitating diffusion of substances between the cerebrospinal fluid and the interstitial fluid of the brain and spinal cord.

    Membrane Potential

    • All cells possess a membrane potential, a difference in electrical charge across their cell membranes.
    • Nerve cells and muscle cells (excitable cells) can rapidly change their membrane potential to generate signals.
    • In resting state, the inside of nerve cells is negative relative to the outside.
    • This voltage difference is maintained by differences in concentration of ions (K+, Na+) and the selective opening and closing of sodium and potassium channels in the cell membrane.
    • The sodium-potassium pump actively transports sodium ions out of the cell and potassium ions in, using ATP.

    Depolarization and Repolarization

    • Depolarization is the rapid reversal of the membrane potential from its resting state, allowing neurons to transmit signals.
    • This occurs when sodium channels open, permitting sodium ions to flow into the cell, making the inside positive.
    • Repolarization restores the resting membrane potential by closing sodium channels and opening potassium channels, allowing potassium ions to move out of the cell, making the inside negative again.
    • A wave of depolarization and repolarization travels rapidly along the axon, constituting a nerve impulse.
    • This electrical signal is converted to chemical communication at the axon terminal where neurotransmitters are released into the synapse.

    Myelin and Conduction Speed

    • Myelin acts as an insulator, speeding up action potential conduction along the axon.
    • In unmyelinated axons, sodium channels must open along the entire length of the axon, slowing down conduction.
    • Myelin creates "tunnels" that allow action potentials to travel quickly between sodium channels that are spaced farther apart, increasing conduction speed.

    Nervous System Divisions

    • The nervous system is divided into two main parts:
      • Central Nervous System (CNS): Consists of the brain and spinal cord.
      • Peripheral Nervous System (PNS): Consists of the spinal nerves and cranial nerves, responsible for connecting the CNS to the rest of the body.
    • The PNS is further divided into:
      • Somatic nervous system (SNS): Controls voluntary actions involving skeletal muscles, joints, tendons, and skin.
      • Autonomic nervous system (ANS): Controls involuntary actions involving glands and organs:
        • Sympathetic nervous system (fight or flight): Controls short-lived responses, increasing heart rate, respiration, and adrenaline release, while suppressing non-essential processes like digestion.
        • Parasympathetic nervous system (rest and digest): Maintains stable body functioning in normal conditions.
        • Enteric nervous system: Innervates the gastrointestinal tract, pancreas, and gallbladder.

    Sensory and Motor Functions

    • The nervous system can be divided based on function:
      • Motor (efferent): Transmits signals from the NS to effectors (muscles or glands) to elicit responses.
        • Somatic motor functions: Control movement of skeletal muscles.
        • Autonomic motor functions: Control movement of smooth muscles and gland activity.
      • Sensory (afferent): Transmits signals from sensory receptors to the CNS.
        • Somatic sensory functions: Detect senses like touch, taste, smell, hearing, vision, balance, joint positions, and muscle length.
        • Autonomic sensory functions: Monitor blood chemistry, visceral organ stretch, blood pressure, and other internal states.

    Reflex Arc

    • A reflex arc is a neural pathway that allows for rapid and automatic responses to stimuli.
    • Components of a reflex arc:
      1. Sensory receptor detects a stimulus.
      2. Sensory neuron transmits the signal to the CNS.
      3. Interneurons within the CNS process the signal.
      4. Motor neuron transmits the signal to the effector.
      5. Effector (muscle or gland) responds to the stimulus.
    • Example: Stretch reflex (somatic) - a reflex to a tap on the knee.
      1. Muscle is stretched by the tap.
      2. Sensory receptors in the muscle detect the stretch.
      3. Action potentials travel via the sensory neuron to the spinal cord.
      4. Sensory neuron synapses with a motor neuron in the spinal cord.
      5. Motor neuron sends action potentials, causing muscle contraction and the kicking response.

    Reflex Testing

    • Reflex testing can diagnose abnormalities in the nervous system.
    • Absent or altered reflexes can indicate damage to the CNS or PNS.
    • For instance:
      • An absent knee jerk response suggests nerve damage.
      • Continual reflex jerks after the tap may indicate cerebellar disease.

    Primitive Reflexes

    • Primitive reflexes are present in infants to aid survival but typically disappear as we mature.
    • Examples of primitive somatic reflexes:
      • Moro reflex: A startled response to a dropped head (arms spread out).
      • Babinski (plantar withdrawal) reflex: Toes fan out when the sole of the foot is stroked.
      • Stepping reflex: Stepping motions when the sole of the foot touches a surface.
      • Rooting reflex: Infants turn their head toward stroking on the cheek and make sucking motions.
      • Grasping reflex: Closing of the hand when a finger is placed in the open palm.
    • Presence of these reflexes in older children or adults suggests potential neurological issues.

    The 12 Cranial Nerves

    • Cranial nerves are 12 pairs of nerves originating from the brain and supplying various structures.
    • Each cranial nerve has a specific function:
      • I (Olfactory): Smell.
      • II (Optic): Vision.
      • III (Occulomotor): Eye movements (up/down/in), pupil constriction, eyelid raising.
      • IV (Trochlear): Eye movements (down & in-diagonal).
      • V (Trigeminal): Sensation to head and face, movement of chewing muscles.
      • VI (Abducens): Eye movement (out).
      • VII (Facial): Taste from anterior tongue, facial expression muscles.
      • VIII (Auditory/Vestibulocochlear): Hearing and balance.
      • IX (Glossopharyngeal): Taste from posterior tongue, swallowing, salivary secretion.
      • X (Vagus): Sensory and motor autonomic supply to most organs.
      • XI (Accessory): Movement of neck muscles, swallowing, vocal cords.
      • XII (Hypoglossal): Tongue movements.

    Special Sensory Organs

    • Smell (olfaction): To detect odor, discriminate good from bad food, and recognize potential dangers (fire).
      • Olfactory receptors (chemoreceptors) detect chemical changes dissolved in mucus in the nose and convert them into electrical impulses sent to the olfactory nerves.
    • Vision: For survival and daily activities.
      • Light enters the eye through the cornea, is focused by the lens, and projected onto the retina.
      • Photoreceptors (rods and cones) in the retina convert light into electrical impulses sent to the brain via the optic nerve.
      • Cones detect color and provide sharper vision than rods.
      • Rods detect low-light vision.
    • Taste (gustation): To identify the type (sweet, sour, salty, bitter, umami) and quality of food.
      • Taste buds located on papillae on the tongue contain gustatory receptors (chemoreceptors) that send signals to the gustatory cortex in the brain.
    • Hearing and Equilibrium: For communication, detecting danger, and maintaining balance.
      • Sound vibrations are captured by the pinna, transmitted to the eardrum and then amplified by the ossicles (malleus, incus, stapes) in the middle ear.
      • These vibrations are converted into electrical signals by inner hair cells in the cochlea (inner ear) and transmitted to the auditory cortex via the auditory nerve..
      • Fluid movement in the semicircular canals and vestibule within the inner ear activates equilibrium receptors and hair cells, providing information about the position of the head in space.

    Touch, Pain, and Proprioception

    • Touch: Sense of pressure, texture, and form on the skin.
      • Detected by touch receptors, temperature receptors, and pain receptors.
    • Pain: Feeling of noxious stimuli.
      • Detected by nociceptors (pain receptors).
    • Proprioception: Sense of joint position and muscle length.
      • Detected by muscle spindles (stretch receptors) and Golgi tendon organs (stretch receptors in tendons).

    Sensory Information in Spinal Nerves

    • Spinal nerves carry sensory information about touch, temperature, muscle length, pain, and joint position.

    • Afferent neurons in spinal nerves transmit this sensory information to the CNS.### Spinal Nerves

    • Spinal nerves emerge from the spinal cord between each vertebra, there are 31 pairs

    • Cervical nerves exit above the vertebrae, all other spinal nerves exit below

    • Damage to a spinal nerve affects the region of the body corresponding to its level of emergence

    • Dermatomes are regions of skin supplied by sensory nerve fibers from a particular spinal nerve

    • Myotomes are muscles supplied by motor nerve fibers from a particular spinal nerve

    • Shingles is a virus that travels along nerves and causes a painful skin eruption corresponding to the involved spinal nerve

    Reflex Testing

    • Reflex testing can be used to distinguish between damage to a motor neuron within the spinal cord and damage to a motor neuron within a spinal nerve
    • Loss of reflex activity indicates nerve damage at the level of the spinal nerve
    • Increased reflex activity (hyperreflexia) indicates damage to the upper motor neuron within the spinal cord

    Spinal Cord Organization and Injuries

    • Sensory neurons enter the spinal cord through the dorsal root
    • Motor neurons exit the spinal cord through the ventral root
    • Spinal cord injuries are classified as complete or incomplete based on the presence/absence of movement and sensation below the level of the injury
    • Injuries higher on the spinal cord result in greater dysfunction
    • Injury at C4 affects the diaphragm and can compromise breathing

    Ascending Tracts

    • Spinothalamic tract: carries pain, temperature, and crude touch sensory information to the brain. Decussates in the spinal cord.
    • Dorsal column tract: carries fine touch, pressure, and proprioception sensory information to the brain. Decussates in the medulla oblongata.

    Descending Tract

    • Corticospinal (pyramidal) tract: carries motor commands from the brain to voluntary skeletal muscles. Decussates in the medulla oblongata.

    Brain Blood Supply

    • The Circle of Willis provides a backup system to ensure blood flow to the brain even if one of the major arteries is blocked
    • The anterior, middle, and posterior cerebral arteries supply different regions of the brain

    Brain Protection

    • The cranium (skull) is a hard bony structure that protects the brain from injury
    • The meninges are connective tissue layers that surround the brain and spinal cord:
      • Dura mater (outermost)
      • Arachnoid mater (middle)
      • Pia mater (innermost)
    • Cerebrospinal fluid (CSF) cushions and supports the brain and spinal cord, flows through the ventricles and the central canal
    • The blood-brain barrier (BBB) is a selectively permeable barrier that protects the brain from harmful substances in the blood

    Blood-Brain Barrier Permeability

    • Crosses easily: lipid-soluble compounds (O2, CO2, anesthetics), some electrolytes, essential amino acids, glucose, caffeine, certain antibiotics, water
    • Does not cross easily: proteins, protein-bound substances, strongly hydrophilic substances, neurotransmitters
    • The BBB can be compromised by hypertension, hyperosmolarity, infection, trauma, ischemia, inflammation, and pressure

    Intracranial Pressure (ICP)

    • ICP is the pressure within the skull
    • Increased ICP occurs when anything adds volume to the cranial contents (inflammation, hemorrhage, tumor, etc.)
    • Increased ICP can lead to brain compression, herniation, reduced blood flow to the brain, and neurological dysfunction
    • Classic signs of raised ICP include deep irregular respiration, widening pulse pressure, and bradycardia

    Major Brain Regions and Functions

    • Brainstem: controls basic life-sustaining functions (respiration, heart rate, blood pressure)
      • Midbrain: temperature regulation, vision, hearing, sleep/wake cycles
      • Pons: arousal, relaying sensory information
      • Medulla: respiration, heart rate, blood pressure, swallowing
    • Cerebellum: coordinates and controls voluntary movements, maintains balance, and helps with motor learning
    • Cerebrum: responsible for higher-order functions (thinking, language, memory, personality)
      • Frontal lobe: reasoning, planning, movement, emotion
      • Parietal lobe: touch, temperature, pain, pressure
      • Occipital lobe: vision
      • Temporal lobe: hearing, memory, language comprehension

    Limbic System

    • The limbic system is responsible for emotion, memory, and motivation
    • Amygdala: fear and aggression; involved in emotional learning and recognizing fear in others
    • Hippocampus: converting short-term to long-term memory; spatial memory

    Brain Lateralization

    • The left hemisphere is dominant for language and speech in most people (97%)
    • The right hemisphere is dominant for spatial abilities and nonverbal communication

    Stroke Impact

    • The location of a stroke determines the symptoms
    • Left hemisphere stroke: right side paralysis, speech disturbances
    • Right hemisphere stroke: left side paralysis, difficulty with reasoning and problem-solving

    Evolutionary Complexity of Brain Regions

    • The brainstem is the oldest and simplest part of the brain, controlling basic functions
    • The cerebellum developed later and is involved in motor coordination
    • The limbic system evolved with the first mammals and is involved in emotions and memory
    • The cerebral hemispheres are the most recent addition to the brain and are responsible for higher-order functions

    Pharmacology

    • Pharmacology is the study of the origins, nature, chemistry, effect and use of drugs.
    • The two main areas are pharmacodynamics and pharmacokinetics.
    • Pharmacodynamics: the effects of drugs on the body.
    • Pharmacokinetics: the absorption, distribution, metabolism and excretion of the drug.

    Drug Names

    • Generic name: the official non-proprietary name of a drug.
    • Trade name: the commercial brand name given by the company that makes it.
    • Chemical name: the systematic name of the molecular structure of the substance.

    Drug Classification

    • Drugs can be classified by their therapeutic effect or similar action.
      • Benzodiazepines (sedatives): diazepam, midazolam.
      • Non-steroidal anti-inflammatory drugs (NSAIDs): ibuprofen, aspirin.
      • Opioids (narcotic analgesics): morphine, codeine.
      • Specific serotonin reuptake inhibitors (SSRIs): fluoxetine, sertraline.

    Drug Targets

    • Most drugs bind to a specific receptor to produce their action.
    • Receptors for endogenous substances:
      • Opioid analgesics: stimulate opioid receptors (agonist), e.g. morphine.
      • Beta blockers: block noradrenaline (beta) receptors (antagonist).
      • Bronchodilators: stimulate noradrenaline receptors (agonist), e.g. Salbutamol.
    • Transport molecules:
      • SSRIs: inhibit serotonin transporter (decreases re-uptake, increases serotonin effect [antidepressant]).
    • Ion channels:
      • Benzodiazepines: bind to GABA-A receptor & cause GABA neurotransmitter to stay at ion channel, inhibiting it (causing sedation).
    • Enzymes:
      • NSAIDs: inhibit enzyme cyclooxygenase (COX) which turns fatty acids into prostaglandins (reduces inflammation and pain).
      • ACE inhibitors: inhibit angiotensin converting enzyme, stopping conversion of angiotensin I to angiotensin II (lowers BP).

    Pharmacology Terminology

    • Bioavailability: proportion of a drug that enters the circulation after administration.
    • Therapeutic index (or range): comparison of the amount of a therapeutic agent that causes the therapeutic effect to the amount that causes toxicity.
    • Adverse effect: a harmful and undesired effect resulting from a medication.
    • Therapeutic effect: the desired and beneficial consequence of a medical treatment.
    • Contraindication: a reason that makes it inadvisable to prescribe a particular drug or employ a particular procedure or treatment.

    Agonists and Antagonists

    • Agonist: a drug that binds to a receptor and activates its function.
    • Antagonist: a drug that blocks the function of a receptor.

    Affinity, Selectivity, Efficacy and Potency

    • Affinity: tendency for a drug to bind with its receptor.
    • Selectivity: degree to which a drug will bind to certain receptors over others.
    • Efficacy: ability of a drug to produce the desired result.
    • Potency: amount of drug needed to produce a particular effect.

    Pharmacokinetic Processes

    • Absorption: movement of the drug from its administration site into the bloodstream.
      • Factors influencing absorption: route of administration, physiological state, chemical properties of the drug.
    • Distribution: degree to which a drug spreads throughout the body.
      • Factors influencing distribution: molecular size, solubility, blood flow, body composition, removal rate by liver.
    • Metabolism: process by which drugs are broken down into inactive forms.
      • Factors influencing metabolism: efficiency of liver and kidneys, age, diet, hormone balance, drug interactions.
    • Excretion: process by which drug metabolites are removed from the body.
      • Factors influencing excretion: filtration rate in kidneys, rate of metabolism, age, blood flow to kidneys, molecular size, binding characteristics, urination frequency.

    Pharmacokinetic Significance

    • Changes in pharmacokinetic processes can affect the duration of drug action, bioavailability, concentration at the target site, and potency of the drug.
    • Pharmacokinetics is crucial for understanding drug effectiveness and ensuring appropriate dosing and frequency.

    Drug Interactions

    • Interactions affecting absorption: one drug can increase or decrease the total absorption or rate of absorption of another drug.
    • Interactions affecting distribution: drugs can compete for protein binding sites, potentially increasing the free concentration of the drug.
    • Interactions affecting metabolism: drugs metabolized by the same enzyme compete for metabolism, potentially slowing down the clearance of both drugs.
    • Interactions affecting excretion: changes in excretion rate can lead to drug accumulation and potential toxicity.
    • Synergistic effect: two drugs with similar effects can result in an exaggerated combined effect.
    • Potentiating effect: one drug enhances the effect of another without having an effect on its own.
    • Antagonistic effect: two drugs with opposite effects counteract each other.

    Clinical Application of Pharmacology

    • Check for drug interactions.
    • Understand the indications and actions of the drugs.
    • Consult pharmacists for medication reviews.
    • Inquire about complementary therapies, supplements, and non-prescription drugs.

    Neuron Structure

    • Neurons are the cells that make up the nervous system.
    • Neurons are composed of a cell body, dendrites, axon, axon terminal, and myelin sheath.
    • The cell body contains the nucleus.
    • Dendrites receive input from other neurons.
    • Axons transmit electrical impulses (action potentials) from the cell body to the axon terminal.
    • Axon terminals release neurotransmitters that communicate with other neurons or effectors.
    • The myelin sheath insulates axons, increasing the speed of impulse conduction.

    Glial Cells

    • Glial cells support and protect neurons.
    • Types of glial cells include astrocytes, oligodendrocytes, microglia, and ependymal cells.
    • Astrocytes provide structural support, transport substances, and regulate the environment around neurons.
    • Oligodendrocytes produce myelin sheaths in the CNS.
    • Microglia are phagocytic cells that remove debris and pathogens.
    • Ependymal cells line the ventricles of the brain and spinal cord, producing cerebrospinal fluid.

    Membrane Potential

    • Every cell maintains a membrane potential, a difference in electrical charge across its plasma membrane
    • The membrane potential is determined by the concentration of ions inside and outside the cell.
    • Nerve cells and muscle cells are excitable cells that can rapidly change their membrane potential to create signals.

    Depolarization and Repolarization

    • Depolarization is the reversal of the resting membrane potential, making the inside of the cell more positive.
    • Sodium channels open during depolarization, allowing sodium ions to flow into the cell.
    • Repolarization is the restoration of the resting membrane potential, making the inside of the cell more negative.
    • Potassium channels open during repolarization, allowing potassium ions to flow out of the cell.
    • The movement of ions creates an electrical impulse that travels along the axon.

    Myelin Sheath and Impulse Conduction

    • Myelin increases the speed of impulse conduction in axons.
    • Myelin creates a fatty sheath that insulates the axon, preventing the loss of electrical charge.
    • The impulse "jumps" between gaps in the myelin sheath (nodes of Ranvier), increasing the speed of conduction.

    Divisions of the Nervous System

    • The nervous system is divided into the central nervous system (CNS) and the peripheral nervous system (PNS).
    • The CNS consists of the brain and spinal cord.
    • The PNS consists of the spinal nerves and cranial nerves.
    • The PNS is further divided into the somatic nervous system (SNS) and the autonomic nervous system (ANS).
    • The SNS controls voluntary movement of skeletal muscles.
    • The ANS regulates involuntary functions of internal organs, such as heart rate and digestion.

    Autonomic Nervous System

    • The ANS is subdivided into the sympathetic and parasympathetic nervous systems.
    • The sympathetic nervous system prepares the body for "fight or flight" responses.
    • The parasympathetic nervous system promotes "rest and digest" functions.
    • The enteric nervous system is a network of neurons that regulates the gastrointestinal tract.

    Sensory and Motor Functions

    • The nervous system also has sensory and motor functions.
    • Sensory neurons (afferent) transmit information from the environment to the CNS.
    • Motor neurons (efferent) transmit signals from the CNS to muscles and glands, causing responses.

    Reflex Arc

    • A reflex arc is a neural pathway that produces a rapid, involuntary response to a stimulus.
    • The basic components of a reflex arc include a sensory receptor, sensory neuron, interneuron, motor neuron, and effector.
    • The stretch reflex is a simple example of a reflex arc, involving the contraction of a muscle in response to a stretch.

    Reflex Testing

    • Reflex testing is used to assess the integrity of the nervous system.
    • Abnormal reflexes can indicate damage to the CNS or PNS.
    • Examples of primitive reflexes include the Moro reflex, Babinski reflex, and grasping reflex.

    Special Senses

    • Smell (olfaction) allows us to detect odors and discriminate between edible and non-edible substances.
    • Vision enables us to perceive light and form images.
    • Taste (gustation) allows us to detect flavors and identify potential toxins in food.
    • Hearing and Equilibrium are important for communication, balance, and spatial orientation.

    Touch, Pain, and Proprioception

    • Touch allows us to experience pressure, temperature, and texture.
    • Pain is the feeling of discomfort or harm.
    • Proprioception is the sense of joint position and muscle length.

    Spinal Nerves

    • Spinal nerves carry sensory and motor information to and from the spinal cord.
    • Spinal nerves transmit information about touch, temperature, pain, and proprioception.
    • Spinal nerves also control the movement of skeletal muscles and regulate involuntary functions of internal organs.

    Spinal Nerves

    • 31 pairs of spinal nerves emerge from the spinal cord between each vertebra
    • 8 pairs of cervical nerves, 12 pairs of thoracic nerves, 5 pairs of lumbar nerves, 5 pairs of sacral nerves and 1 pair of coccygeal nerves
    • Cervical nerves exit over the top of their corresponding vertebra, while thoracic, lumbar and sacral nerves exit under their corresponding vertebra
    • Spinal nerves can be damaged, resulting in loss of function in the area the nerve supplies
    • Dermatomes: regions of skin supplied by sensory nerves from a particular spinal nerve
    • Myotomes: muscles supplied by motor nerves from a particular spinal nerve

    Neurological Deficits & Symptoms

    • Damage to a spinal nerve can be identified by absent reflexes, paralysis, and loss of muscle tone
    • Damage to a motor neuron in the spinal cord can be identified by excessive reflexes, paralysis, and increased muscle tone
    • Shingles: painful skin eruption caused by a virus that lives in the cell bodies of neurons and travels down axons
    • Referred pain: pain felt in a different location than the source of pain, due to sensory nerves conveying signals from different body regions

    The Central Nervous System

    • The CNS receives, processes, and integrates sensory information and transmits motor commands
    • Sensory nerves: enter the spinal cord via the dorsal root
    • Motor nerves: exit the spinal cord via the ventral root
    • White matter: contains ascending sensory pathways
    • Grey matter: contains descending motor pathways
    • Spinal cord lesions: result in loss of function below the level of the lesion
    • Complete spinal cord injuries: all movement and sensation affected below the level of the lesion
    • Incomplete spinal cord injuries: some movement and sensation remain below the level of the lesion
    • Injury at C4 will compromise breathing

    Spinal Tracts

    • Spinothalamic tract (ascending): carries sensory information about pain, temperature, and light touch to the brain
    • Dorsal column tract (ascending): carries sensory information about pressure, proprioception (muscle length and joint position), and fine touch to the brain
    • Corticospinal (pyramidal) tract (descending): carries motor commands from the brain to skeletal muscles
    • Decussation: the crossing over of nerve tracts from one side of the brain or spinal cord to the other

    Brain Blood Supply

    • The brain receives blood from the internal carotid and vertebral arteries, which form the Circle of Willis
    • The Circle of Willis acts as a backup system in case of blockage of the internal carotid or vertebral arteries
    • Major veins draining blood from the brain: internal jugular veins
    • Cerebrospinal fluid (CSF): circulates through the ventricles of the brain and central canal of the spinal cord, protecting and nourishing the CNS

    Brain Protection

    • Cranium: bony structure that protects the brain
    • Meninges: connective tissue layers that protect the brain and spinal cord (dura mater, arachnoid mater, pia mater)
    • Cerebrospinal fluid (CSF): cushions and supports the brain and spinal cord
    • Blood-brain barrier (BBB): protects the brain from harmful substances in the blood
    • Substances that easily cross the BBB: lipid-soluble compounds, electrolytes, essential amino acids, glucose, caffeine, water, ions
    • **Substances that do not easily cross the BBB: ** proteins, protein-bound substances, hydrophilic substances, neurotransmitters
    • The blood-brain barrier can be compromised by conditions such as hypertension, inflammation, trauma, ischemia, radiation, and infection.

    Intracranial Pressure (ICP)

    • ICP is the pressure inside the skull
    • Increased ICP can be caused by factors such as inflammation, bleeding, tumors, stroke, aneurysm, and space-occupying lesions
    • Increased ICP can lead to reduced blood flow to the brain and compression of brain structures
    • Symptoms of increased ICP include deep, irregular respiration, bradycardia, and widening pulse pressure

    Brain Regions

    • Brainstem: connects spinal cord to the cerebrum, controls vital functions such as breathing, heart rate, and blood pressure
    • Cerebellum: coordinates and controls voluntary movements, posture, balance, and learning of motor skills
    • Cerebrum: largest part of the brain; divided into four lobes (frontal, parietal, occipital, temporal)
    • Limbic System: responsible for emotional responses, memory, and learning

    Evolution of Brain Regions

    • The brainstem evolved first, followed by the cerebellum, limbic system, and then the cerebrum.
    • More complex brain regions evolved later, with the cerebrum being the most complex and responsible for higher-order thinking processes.
    • Cerebral lateralisation: the hemisphere dominant for language and speech is the dominant hemisphere

    Stroke Impact

    • Strokes in different brain regions lead to distinct neurological impairments
    • Right hemisphere stroke: left side paralysis, reasoning problems
    • Left hemisphere stroke: right side paralysis, speech impairment
    • Brainstem strokes: can affect vital functions and lead to coma
    • Symptoms of a stroke depend on the specific brain region affected.

    Cerebellum Stroke

    • Cerebellum stroke can cause lack of coordination (ataxia), clumsiness, balance problems, shaking, and other muscular difficulties.
    • It can make daily activities such as walking, talking, eating, and performing activities of daily living (ADLs) challenging.

    Brain Stem Stroke

    • Brain stem stroke can be life-threatening and disrupt vital autonomic functions.
    • An electroencephalogram (EEG) is used to check the brain's electrical activity.

    Pharmacology

    • Pharmacology is the study of origins, nature, chemistry, effect and use of drugs.
    • Two major branches are pharmacodynamics and pharmacokinetics.
    • Pharmacodynamics studies how drugs affect the body.
    • Pharmacokinetics studies how the body absorbs, distributes, metabolizes, and excretes drugs.

    Drug Nomenclature

    • Drugs can be named generically, by their trade name, or by their chemical name.
    • The generic name is the official non-proprietary name, used in healthcare settings.
    • Trade names are brand names given by manufacturers.
    • The chemical name describes the molecular structure of the drug.

    Drug Classification

    • Drugs can be classified by their therapeutic effect or similar actions.
    • Examples include benzodiazepines (sedatives), non-steroidal anti-inflammatory drugs (NSAIDs), opioids (narcotic analgesics), and selective serotonin reuptake inhibitors (SSRIs).

    Drug Targets

    • Most drugs bind chemically to specific sites within the body to produce their effects.
    • These target sites include:

      Receptors for Endogenous Substances:

      • Opioid analgesics stimulate opioid receptors (agonist) and act as painkillers.
      • Beta blockers block noradrenaline (beta) receptors (antagonist) and are used to manage cardiovascular conditions.
      • Bronchodilators stimulate noradrenaline receptors (agonist) and are used to open airways.

    Transport Molecules:

    - SSRIs inhibit serotonin transporters, increasing free serotonin and leading to an antidepressant effect.

    Ion Channels:

    - Benzodiazepines bind to GABA-A receptors, inhibiting their excitatory action and producing sedation.

    Enzymes

    - NSAIDs inhibit cyclooxygenase (COX) enzyme, reducing inflammation and pain.
- ACE inhibitors inhibit angiotensin-converting enzyme, lowering blood pressure.

    Key Pharmacology Terms

    • Bioavailability: The proportion of a drug that enters the bloodstream after administration and can exert its effects.
    • Therapeutic index (or range): The ratio between the dose of a drug that produces therapeutic effects and the dose that causes toxicity.
    • Adverse effect: A harmful or undesired effect of a medication.
    • Therapeutic effect: The desired and beneficial outcome of a medical treatment.
    • Contraindication: A reason not to use a particular drug or treatment in a patient.

    Agonists and Antagonists

    • Agonist: A drug that binds to and activates a receptor, mimicking the effect of an endogenous substance.
    • Antagonist: A drug that binds to a receptor without activating it, blocking the action of other substances.

    Affinity, Selectivity, Efficacy and Potency

    • Affinity: The tendency of a drug to bind to its receptor. A drug with high affinity binds readily.
    • Selectivity: The degree to which a drug prefers to bind to one receptor over others.
    • Efficacy: The ability of a drug to produce a desired effect at its target.
    • Potency: The amount of drug needed to produce a specific effect. Potency depends on both affinity and efficacy.

    Pharmacokinetic Processes

    • Absorption: Movement of the drug from its administration site into the bloodstream.
    • Distribution: Spread of the drug throughout various compartments of the body.
    • Metabolism: Breakdown of the drug into inactive forms and conversion into more water-soluble forms for excretion.
    • Excretion: Removal of drug metabolites from the body, mainly through the kidneys.

    Factors that Alter Pharmacokinetic Processes:

    • Absorption:
      • Route of administration (oral, intravenous, subcutaneous, intramuscular)
      • Physiological state (e.g., blood flow)
      • Chemical properties of the drug (size, solubility)
    • Distribution:
      • Molecular size
      • Solubility (lipid solubility, impact on blood-brain barrier permeability)
      • Patient's body composition (e.g., fat content)
      • Liver removal rate
    • Metabolism:
      • Liver and kidney efficiency
      • Age
      • Diet
      • Hormone balance
      • Drug interactions
    • Excretion:
      • Kidney filtration rate
      • Metabolism rate
      • Age (decreased filtration rate)
      • Blood flow to kidneys
      • Molecular size of the drug
      • Urinary frequency

    Importance of Pharmacokinetics

    • Pharmacokinetic factors can influence the effectiveness of a drug by affecting its duration of action, bioavailability, concentration at the target site, and potency.
    • If the body breaks down a drug before it reaches its target, its therapeutic effect may be reduced.
    • Dose and frequency of administration need to consider both pharmacodynamics and pharmacokinetics for optimal effect.

    Drug Tolerance

    • Prolonged use of a drug can lead to the body compensating for its presence, requiring higher doses for the same effect (upregulation) or lower doses for the same effect (downregulation).

    Drug Interactions

    • Absorption interactions: One drug can increase or decrease the rate or amount of absorption of another drug.
    • Distribution interactions: Two drugs competing for the same protein binding sites can affect the distribution of both.
    • Metabolism interactions: Drugs metabolized by the same enzymes can compete for those enzymes, slowing metabolism.
    • Excretion interactions: Changes in the excretion rate can cause the accumulation of drug metabolites in the body.

    Outcomes of Drug Interactions

    • Synergistic effect: Two drugs with similar effects can have an exaggerated effect when combined.
    • Potentiating effect: One drug enhances the effect of another.
    • Antagonistic effect: Two drugs with opposite effects can cancel each other out.

    Clinical Implications of Pharmacology

    • Always check the Medications Information Sheet (MIMS) for potential drug interactions.
    • Be knowledgeable about the drugs you are administering, their indications, and their mechanisms of action.
    • Consult with a pharmacist for medication review.
    • Inquire about non-prescription drugs, complementary therapies, and supplements patients are taking, as these can interact with prescription drugs.

    Chemotherapy

    • Aims to destroy fast-growing cancer cells.
    • It can also affect healthy cells, causing side effects like hair loss, reduced immunity, and digestive problems.
    • Exploits differences between cancer cells and healthy cells to kill cancer cells specifically.

    Targets of Antibacterial, Antifungal, Antiviral, and Cytotoxic Drugs

    • Antibacterial Drugs:
      • Inhibit DNA/RNA synthesis (e.g., quinolones)
      • Inhibit cell wall synthesis (e.g., penicillins)
      • Inhibit protein synthesis (e.g., tetracyclines, aminoglycosides)
      • Disrupt cytoplasmic membrane (e.g., polymixins)
      • Inhibit general metabolic pathways (e.g., sulfonamides)
    • Antifungal Drugs:
      • Inhibit cell wall synthesis (e.g., caspofungin, micafungin)
      • Inhibit ergosterol synthesis (e.g., fluconazole, ketoconazole)
      • Interrupt membrane function (e.g., nystatin, amphotericin)
    • Antiviral Drugs:
      • Block virus attachment to cells (drugs under development)
      • Inhibit uncoating (e.g., amantadine, rimantadine, arbidol)
      • Stop virus replication (e.g., polymerase inhibitors, reverse transcriptase inhibitors)
      • Block assembly of new virions (e.g., protease inhibitors)
      • Inhibit budding off (e.g., neuraminidase inhibitors - oseltamivir)
    • Cytotoxic Drugs:
      • Drugs target specific aspects of tumor cells, aiming to kill them selectively.

    Drug Resistance

    • Drug resistance occurs when pathogens mutate in a way that allows them to survive against drugs designed to kill them.
    • This is an example of natural selection.
    • Overuse and misuse of antibiotics can lead to bacteria developing resistance and spreading the resistant gene through plasmids.

    Neurotransmitters

    • Acetylcholine is involved in voluntary movement, learning, memory, and other functions.
      • Excessive acetylcholine can cause depression.
      • Deficiencies in the hippocampus are linked to dementia.
    • Noradrenaline (Norepinephrine) is important for attentiveness, emotions, sleep, dreaming, and learning.
      • Plays a role in mood disorders like manic depression.
      • Released into the bloodstream during "fight or flight" situations to increase heart rate.
    • Adrenaline (Epinephrine) causes vasodilation, bronchodilation, and increases blood glucose and fatty acids to provide energy for "fight or flight".
      • Deficiencies are associated with depression.
    • Dopamine regulates motor behavior, pleasure, motivation, emotional arousal, and dependency.
      • Excess dopamine is associated with schizophrenia.
      • Deficiencies are linked to some forms of depression and symptoms of Parkinson's disease.
    • Serotonin regulates sleep, appetite, memory, learning, temperature, mood, behavior, muscle contraction, and functions of the CNS and endocrine system.
      • Deficiencies are linked to depression, anxiety disorders, and OCD.
    • GABA inhibits brain activity and has sedative effects.
      • Deficiencies are associated with anxiety and anxiety disorders.
      • Some anti-anxiety medications increase GABA at receptor sites and are used to treat epilepsy and tremors associated with Huntington's disease.
    • Endorphins link pain to the emotional centers of the brain and can produce analgesia.
      • They elicit pleasure or euphoria during exercise, orgasm, love, and when eating spicy food.
      • Have been used to treat depersonalization disorder.

    Antidepressants

    • Antidepressants work by increasing the amount of a neurotransmitter in a certain area of the brain.
    • This is achieved by inhibiting the reuptake of these neurotransmitters.
    • Antidepressants are classified into six main families from oldest to newest:
      • Monoamine oxidase inhibitors (MAOIs)
      • Tricyclics
      • Selective serotonin reuptake inhibitors (SSRIs)
      • Noradrenaline-serotonin reuptake inhibitors (NSRIs)
      • Selective noradrenaline reuptake inhibitors (SNRIs)
      • Noradrenaline-dopamine reuptake inhibitors (NDRIs)
    • Newer antidepressants are more selective in their action, resulting in fewer side effects and suitability for long-term use.

    Treatment for Mania

    • Lithium is used to treat mania by causing a mood-stabilizing effect by altering the function of several neurotransmitters.
    • If lithium fails, other drugs such as anticonvulsants, sedatives, or antipsychotics may be tried.
    • Lithium limits the occurrence of manic or depressive episodes.
    • It has a narrow therapeutic index, meaning blood levels need to be closely monitored.
    • Toxic doses can lead to confusion, seizures, and coma.
    • Side effects include: fine muscle tremor, nausea, vomiting, diarrhea, polydipsia, thirst, loss of appetite, and kidney failure.

    Autonomic Neurotransmitters

    • The sympathetic division (fight or flight) is controlled by noradrenaline and adrenaline.
    • The parasympathetic division (rest and restore) is controlled by acetylcholine.

    Adrenoceptors or Adrenergic Receptors

    • Alpha receptors (α): Found in blood vessels and the brain.
      • α1: Causes vasoconstriction, reducing blood flow to the gut, kidney, and bladder.
      • α2: Found in the brain and acts as a presynaptic receptor, decreasing noradrenaline release.
    • **Beta receptors (β): ** Found in the heart, bronchioles, blood vessels, and fat cells.
      • β1: Found in the heart, increasing heart rate and strength of beat.
      • β2: Found in the bronchioles and blood vessels, causing bronchodilation and vasodilation, increasing blood flow to the heart, lungs, and muscles.
      • β3: Found in fat cells, mobilizing fat for energy.

    Cholinergic Receptors

    • Nicotinic: Found on skeletal muscle and activated by exogenous nicotine. This receptor causes muscle contraction.
    • Muscarinic: Found in the brain and on organs and glands. They are activated by exogenous muscarine (found in some mushrooms) and produce parasympathetic responses.

    Clinical Applications for Autonomic Drugs

    • Treatment of hypertension (antihypertensives e.g. beta-blockers (β antagonist)
    • Reduction of risk of cardiac arrhythmia after myocardial infarction (beta-blockers)
      • Treatment of asthma (Salbutamol (β2 agonist)
    • Treatment of glaucoma (beta-blockers (β antagonist))
    • Treatment of nasal congestion
    • Treatment of diarrhea and motion sickness (muscarinic antagonists)
    • Emergency resuscitation (cardiac arrest) and anaphylaxis (β1 agonist, inject adrenaline)

    Analgesic Drugs

    • Pain is both a sensory and emotional experience. It serves as a protective mechanism, helping us remember experiences that cause pain and avoid them in the future.
    • Non-steroidal analgesics (NSAIDs):
      • Block the production of chemical stimuli of pain to the brain.
      • Inhibit the enzyme cyclooxygenase (COX), which is required for the production of prostaglandins.
      • This inhibition causes an analgesic, anti-inflammatory, and anti-pyretic response by suppressing pain, reducing inflammation, and lowering temperature.
      • Examples: Aspirin (acetylsalicylic acid), Nurofen (Ibuprofen), Celebrex (Celecoxib)
    • Narcotic Analgesics (opiates):
      • Dampen down the emotional response to injury, reducing the number of pain impulses sent to the brain and activating an inhibitory reaction.
      • They act as agonists at endogenous opioid receptors, a system that "dampens down" pain signals in situations of extreme pain or stress.
      • Our endogenous opioids are beta endorphin, enkephalins, and dynorphin.
      • Examples: morphine, codeine, methadone, pethidine, fentanyl.
      • Effects of opioid agonists (opiates):
        • Analgesia
        • Constriction of pupils
        • Sedation
        • Cough suppression (only codeine and pholcodine)

    Side Effects of Narcotics

    • Constipation
    • Light-headedness, Dizziness, Drowsiness
    • Stomach upset, Nausea, Vomiting
    • Sphincter of Oddi and ureter spasms (morphine)
    • Anxiety
    • Appetite suppression
    • Tolerance and dependence
    • Itching
    • Respiratory depression or shortness of breath
    • Irregular heartbeat or bradycardia
    • Tremors
    • Seizures

    Signs of Opioid Overdose

    • Pinpoint pupils
    • Decreased respiratory rate (sometimes apnoea)
    • Coma
    • Hypotension
    • Convulsions

    Treatment of Opioid Overdose

    • Use of an opioid antagonist (antidote) such as naloxone or naltrexone.
    • In addicts, large doses might precipitate a rapid withdrawal syndrome. The patient will regain consciousness.
    • Antagonists might need to be titrated to reduce respiratory depression while maintaining sedation.
    • Naloxone has a short duration of action, requiring repeated dosing to prevent relapse.

    Tolerance and Dependence

    • Tolerance: the body's state of reduced sensitivity to a drug when given in regular doses.
    • Larger doses are required to produce the same therapeutic effect.
    • Tolerance is reversible.
    • Dependence is the physiological or psychological adaptation of the body to the presence of a drug.
    • When the drug is suspended or counteracted by an antagonist, the body goes into withdrawal.

    Removal of Neurotransmitters from the Synaptic Cleft

    • After an action potential is transmitted to the postsynaptic neuron, neurotransmitters in the synaptic cleft are reabsorbed into the presynaptic neuron through channels in the membrane.
    • This process is called reuptake.

    Drug Manipulation of Neurotransmitter Removal

    • Agonist drugs: Bind to receptors on the postsynaptic neuron to simulate (change) or enhance a neurotransmitter's actions. They can also block reuptake, causing more neurotransmitter to bind to receptors and increase its effects.
    • Antagonist drugs: Block receptors, inactivating them by taking up space, causing the neurotransmitter's effect to be nullified or diminished.

    Major Types of Microorganisms That Cause Disease in Humans

    • Fungi: Eukaryotes with rigid cell walls composed of chitin and glucan. They can be unicellular (yeasts) or multicellular (moulds).
    • Protozoa: Unicellular eukaryotes without a nucleus but with membrane-bound organelles.
    • Bacteria: Unicellular prokaryotes without a nucleus or membrane-bound organelles. They have a cell membrane surrounded by a cell wall and possess external structures like flagella and pili.
    • Viruses: Lack a nucleus, organelles, and cytoplasm, but have genetic material. They can only replicate inside host cells.
    • Parasites:
      • Endoparasites: Live inside the body. Examples: Helminth worms.
      • Ectoparasites: Live on the surface of the body. Examples: fleas, lice, mites.

    Key Fungi, Protozoa, and Multicellular Parasites That Infect Humans

    • Fungi:
      • Moulds: Often involved in food spoilage and production. Penicillium mould produces penicillin antibiotic by preventing bacterial cell wall synthesis.
      • Fungal Infections:
        • Superficial mycoses: Affect the outermost layer of skin or hair (e.g., tinea versicolor).
        • Cutaneous mycoses: Colonize the skin, extending deeper into the epidermis (e.g., athlete's foot, ringworm).
        • Subcutaneous mycoses: Affect the epidermis, dermis, muscle, and bone. They usually enter through skin trauma and are difficult to treat (e.g., mycetoma, Candida albicans).
        • Systemic mycoses: Affect internal organs. Entry usually occurs through inhalation of spores. They are often dimorphic (e.g., histoplasmosis (from soil, affects lungs), Pneumocystis pneumonia).
    • Protozoa:
      • Entamoeba histolytica: Major cause of dysentery. They invade the intestinal wall, causing abscesses, ulcers, and diarrhea.
      • Giardia Intestinalis: Attaches to the small intestine, leading to the release of tissue fluids, diarrhea, malaise, and gas.
      • Malaria: Caused by Plasmodium parasites transmitted through mosquito saliva. They develop in the liver, invade red blood cells, and rupture them.
    • Parasites:
      • Endoparasites - Helminth Worms:
        • Flatworms: Flukes and tapeworms
        • Nematodes: Roundworms
      • Ectoparasites:
        • Fleas: Blood-sucking parasites that can carry pathogenic organisms.
        • Lice: Cause redness and itching (e.g., Pediculus humanus (hair lice)).
        • Mites: Burrow into skin and lay eggs. They can produce allergens and cause redness and inflammation (e.g., Sarcoptes scabei (causes scabies)).

    Bacterial Structure and Physiology

    • All bacteria have a cell (plasma) membrane, but most also possess an outer cell wall composed primarily of peptidoglycan.
    • This structural difference is the basis for the Gram stain:
      • Gram-positive Bacteria: Thick peptidoglycan layer on the outside of the cell wall.
      • Gram-negative Bacteria: Thin peptidoglycan layer covered by an outer membrane. These bacteria also contain lipopolysaccharide (LPS), which is also known as endotoxin and responsible for toxic effects in Gram-negative infections.

    Bacteria Structure and Function

    • Glycocalyx: Surrounding slime layer that protects bacteria
    • Flagella: Attached for motility
    • Pili and Fimbriae: Pili for conjugation and genetic material transfer, fimbriae for attachment to surfaces including host tissue
    • Cell Wall: Determines shape, protects against osmotic lysis and some toxic substances, contains components contributing to pathogenicity
    • Endotoxins: Formed only by Gram-negative bacteria, part of the cell wall, released upon bacterial death, can cause fever and systemic symptoms
    • Exotoxins: Formed by both Gram-positive and Gram-negative bacteria, excreted by microorganisms or released upon cell lysis, highly toxic, can destroy cells and disrupt cell metabolism

    Bacterial Growth

    • Bacteria reproduce by binary fission
    • Generation Time: Time for bacteria to reproduce, can be as little as 20 minutes or several hours
    • Four Phases of Growth:
      • Lag Phase: Bacteria assess environment before replicating
      • Exponential Phase: Rapid doubling and replication, causing a spike in bacteria numbers
      • Stationary Phase: Limited nutrients or space for further replication
      • Decline Phase: Environment can no longer support bacterial growth, some bacteria die
    • Pure Cultures: Often taken to increase bacterial numbers, grown on nutrient-rich agar plates

    Bacterial Identification

    • Gram Stain: Gram-positive bacteria stain purple, Gram-negative bacteria stain pink
    • Other Stains: Used to identify flagella, capsule, etc.
    • Other Identification Factors:
      • Cell morphology
      • Colony morphology
      • Aerobic or anaerobic growth
      • Specialized nutritional requirements

    Serological Tests

    • Detect specific antibodies

    Molecular Techniques

    • Polymerase Chain Reaction (PCR): Detects nucleic acid sequences

    Biochemical Tests

    • Identify enzyme production or sugar metabolism

    Virion Structure

    • Naked Viruses: Viral DNA and RNA surrounded by a protein shell (capsid), providing protection from destruction, capsid has distinctive antigenic structure
    • Enveloped Viruses: Have an outer coat (envelope) derived from the host cell's lipid bilayer, envelope contains proteins that project as spikes (peplomers) involved in attachment to host cells

    Viral Replication

    • Polymerase Enzyme: Enables insertion into host DNA using host's replication machinery
    • Haemagglutinins: Antigenic glycoproteins on viral surface, bind virus to host cells
    • Neuraminidase: Enzymes on viral surface, act on infected cell surface to release viral progeny
    • Viral Mutations: Viruses lack mechanisms to correct mutations or ensure DNA stability, resulting in different strains (often more virulent)
    • Basic Viral Infection and Replication Steps:
      • Adsorption: Virus binds to host cell
      • Penetration: Virus injects its genome into host cell
      • Viral Genome Replication: Viral genome replicates using host's cellular machinery
      • Assembly: Viral components and enzymes are produced and begin to assemble
      • Maturation: Viral components assemble and viruses fully develop
      • Release: Newly produced viruses are expelled from the host cell

    Flu Virus Naming

    • H = Haemagglutinins, N = Neuraminidase (H + N): Types of spikes and enzymes on a viral cell surface
    • H1N1 (Spanish flu): Killed up to 100 million worldwide
    • H2N2 (Asian flu): Estimated 1-4 million deaths
    • H1N1 (Swine flu): Declared pandemic in 2009, low mortality rate
    • H5N1 (Bird flu): Around 240 deaths, millions of birds killed/culled

    Immune System Overview

    • Immune System: Dynamic communication network that defends the body against foreign organisms, recognizes infection, and initiates protective countermeasures.

    Lymphatic System

    • Lymphatic System: Network of vessels that collect and filter interstitial fluid (lymph) through lymph nodes, removing foreign materials
    • Part of the circulatory system
    • Houses and transports white blood cells.
    • Lymph nodes become swollen and painful during infection

    Immune Response Types

    • Innate Response: Non-specific, present at birth, quicker response
    • Adaptive Response: Specific, builds up over time, slower response but has memory of antigens

    Innate Immunity Components

    • Physical Barriers: Skin, mucous membranes, cilia
    • Chemicals: Enzymes, pH extremes, high salt concentration, interferons, complement, lysozyme
    • Phagocytosis: Performed by neutrophils, dendritic cells, eosinophils, monocytes, and macrophages
    • Natural Killer (NK) Cells: Circulate in blood, check for foreign material, release enzymes that cause apoptosis
    • Inflammation: Triggered by tissue damage, involves redness, swelling, heat, and pain
    • Fever: Body temperature above 37.2°C, inhibits some viruses and bacteria, raises metabolic rate

    Innate Immunity Cells

    • Granulocytes:
      • Neutrophils: Most abundant, first line of defense against bacteria, phagocytosis, activation of bacterial mechanisms
      • Eosinophils: Role in inflammatory and allergic responses, phagocytosis of antibody-coated parasites
      • Basophils: Least abundant, release histamine and heparin, involved in inflammatory and allergic responses
    • Agranulocytes:
      • Monocytes: Circulate in blood, differentiate into macrophages and dendritic cells
      • Macrophages: Phagocytosis, activation of bacterial mechanisms, antigen presenting
      • Dendritic Cells: Phagocytosis of pathogens, present antigens to T cells
      • Lymphocytes:
        • NK Cells: Circulate in blood, check for foreign material, cause apoptosis in infected cells
    • Mast Cells: Release histamine and other active agents to increase capillary permeability
    • Basophils: Promote allergic responses, augment anti-parasitic immunity
    • Pattern Recognition Receptors: Recognise a range of antigens
      • Toll-Like Receptors: Act as 'mines', respond to pathogens, release cytokines
    • Interferons: Cytokines released by infected cells to alert surrounding cells to produce antiviral proteins
    • Complement: Proteins in blood that generate rapid response to stimuli
      • Functions: opsonisation, chemotaxis, cell lysis, clumping of antigens
      • Activation Pathways:
        • Classical Pathway: Triggered by antibody bound to pathogen
        • Alternative Pathway: Activated by direct recognition of microbial structures
        • Lectin Pathway: Activated by binding of mannose-binding lectin to microbial glycoproteins and glycolipids

    Adaptive Immunity Components

    • Lymphocytes:
      • T Cells:
        • Th Cells: Activate cytotoxic T cells and B cells
        • Tc Cells: Recognize targets using MHC I, release cytokines to cause apoptosis in infected cells
        • Ts Cells: Regulate immune system, turn off response when antigen is gone
        • Tm Cells: Remember specific antigens for future exposures
      • B Cells:
        • Produce plasma cells (antibody production) and memory B cells (antigen memory)
    • Antibodies: Glycoproteins (immunoglobulins) specific to an antigen, inactivate antigens

    Inflammation

    • Triggers: Tissue damage or killing
    • Characteristics: Redness, swelling, heat, pain
    • Mechanism: Increased capillary wall permeability, WBC leakage, macrophage activity, interleukin secretion

    Adaptive Immunity Divisions

    • Humoral Immunity: Involves helper T cells and B cells binding to MHC II, antibodies perform immune function
    • Cellular Immunity: Involves helper and cytotoxic T cells binding to MHC I, cells perform immune function

    B Cell Activation and Antibody Function

    • T Cell-Dependent Activation: Antigen binds to MHC II, presented to Th cells, activates B cells into plasma and memory cells, plasma cells produce antibodies
    • T Cell-Independent Activation: B cells directly attach to an epitope, recognise it as foreign and destroy the entire antigen
    • Antibody Types:
      • IgM: Primary response, first antibodies to appear after infection, short-lived
      • IgG: Secondary response, most abundant antibody, can easily enter tissues, cross placenta
      • IgA: Predominant in saliva, mucus, milk, and tears, also circulates in blood
      • IgE: Attaches to basophils and mast cells, stimulates histamine release, involved in inflammatory and allergic responses, effective against parasitic worms
      • IgD: Role in B cell development and activation

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