NERVOUS System PDF

NERVOUS Neuron Anatomy: 1. Cell body Functions of the Nervous System Center of the neuron and contains the 1. Sensory input – gathering information organelles ∙ To monitor changes occurring i...

NERVOUS Neuron Anatomy: 1. Cell body Functions of the Nervous System Center of the neuron and contains the 1. Sensory input – gathering information organelles ∙ To monitor changes occurring inside and outside the body (changes = stimuli) 2. Dendrites conduct impulses toward the 2. Integration cell body ∙ to process and interpret sensory input and decide if action is needed. 3. Axons conduct impulses away from 3. Motor output the cell body ∙ A response to integrated stimuli ∙ The response activates muscles or glands 4. Myelin sheath Covers the axon and helps FUNCTIONS OF THE NERVOUS SYSTEM speed neural impulses 5. Node of ranvier Receiving sensory input Makes the transfer of information faster Integrating information 6. Axon terminal Controlling muscles and glands Form junctions with other cells Maintaining homeostasis Establishing and maintaining mental activity TYPES OF NEURONS: ARROWS INDICATE EXCITATION FLOW Nervous Tissue: Neurons ∙ Neurons = nerve cells BIPOLAR - RARE , FOUND ON RETINA ∙Functional unit of the nervous system OF THE EYE AND GANGLEA ∙Cells specialized to transmit messages UNIPOLAR - “AKA PSEUDO UNIPOLAR” ORIGINATES AS BILOPAR MULTIPOLAR - MOST COMMON TYPE Nervous tissue: Support Cells 1. Astrocytes(CNS) 4. Oligodendrocytes(CNS) Star-shaped that encircles blood vessels Produce myelin sheath in the central and nerves thus provides blood-brain barrier nervous system 2. Microglia (CNS) 5. Satellite cells(PNS) Spider-like phagocytes Protect neuron cell bodies 3. Ependymal cells (CNS) 6. Schwann cells(PNS) Form myelin sheath in the peripheral * NONCILIATED - produces cerebrospinal nervous system fluid (CSF) * CILIATED - responsible for transport or circulation of CSF NOTE: CEREBROUS SPINAL FLUID ”CSF” - FLUID IN SPINAL CHORD THAT PROTECTS IT FROM SHOCK, SUPPLIES NUTRIENTS TO NERVOUS SYSTEM, Problems with bowel and bladder function AND REMOVES WASTE PRODUCTS. BLOOD-BRAIN BARRIER 4 FEATURES OF THE BRAIN: MULTIPLE SCLEROSIS Potentially disabling disease of the brain 1.Bone and spinal cord Brain - cranium Spinal cord - vertebrae The immune system attacks the protective * Inner membrane: meninges sheath (myelin) that covers axons 2.Cerebrospinal fluid Signs and symptoms protects brain and spinal cord from trauma supplies nutrients to nervous system tissue Numbness or weakness in one or more removes waste products from cerebral limbs that typically occurs on one side of metabolism your body at a time, or the legs and trunk Partial or complete loss of vision, usually 3. Astrocytes in one eye at a time, often with pain during blood-brain barrier eye movement supplying nutrients to nerve tissue and Prolonged double vision aiding in post-traumatic repair and scarring Tingling or pain in parts of your body processes Electric-shock sensations that occur with certain neck movements, especially bending 4.Tissues the neck forward Gray matter - contains the cell bodies, (Lhermitte sign) dendrites and axon terminals of neurons, Tremor, lack of coordination or unsteady White matter - made of axons connecting gait different parts of grey matter to each other Slurred speech Fatigue, dizziness RESTING MEMBRANE POTENTIAL A resting (non-signaling) neuron has a voltage across its membrane called the resting membrane potential, or simply the resting potential. The resting potential is determined by concentration gradients of ions across the membrane and by membrane permeability to each type of ion. NEURO TRANSMITTER ∙ Chemicals messengers that transmit signals from a neuron to a target cell across a synapse. The target cell may  DEPRESSION Major depression is characterized by intense feelings of sadness. Dysthymic disorder is less intense. type of depression, but it persists for a "longer period of time (years). Adjustment disorders occur when (an individual's response to a stressful avert. be a neuron or some other kind of cell. Postpartum depression is ALZHEIMER’S DISEASE depression that occurs after giving birth Most common form of dementia Manic depression or bipolar disorder is Associated with a decrease in a brain disorder that causes unusual shifts Acetylcholine-secreting neurons in a person's mood. Psychotic depression includes some features of psychosis, such as hallucinations or delusions. Seasonal affective disorder (SAD) is a toe of depression that comes on in the winter months when the sun is sparse. BOTULISM Caused by toxin of Clostridium botulinum Blocks the release of acetylcholine from the presynaptic terminal MAJOR DEPRESSIVE DISORDER -Depressed mood or a loss of interest or pleasure in daily activities for more than two weeks -Mood represents a change from the person's baseline -Impaired function: social, occupational, educational -Specific symptoms, at least 5 of these 9, present nearly every day -Depressed mood or irritable most of the day, nearly every day, as indicated by either subjective report (e.g., feels sad or empty) or observation made by others (e.g., appears tearful) -Decreased interest or pleasure in most activities, most of each day -Significant weight change (5%) or change in appetite -Change in sleep: Insomnia or hypersomnia -Change in activity: Psychomotor agitation or retardation -Fatigue or loss of energy -Guilt/worthlessness: Feelings of worthlessness or excessive or inappropriate guilt -Concentration: diminished ability to think or concentrate, or more indecisiveness -Suicidality: Thoughts of death or suicide, or has suicide plan COCCAINE Acts by inhibiting the reuptake of norepinephrine MORPHINE Mimics endorphins, the “happy hormone” SPINAL CORD  Extends from the foramen magnum to ⚫ Cervical plexus (C1 to C4) the level of the 2nd lumbar vertebra ⚫ Brachial plexus (C5 to T1) ⚫ Lumbosacral plexus (L1 to L4-S1 to S4) PLEXUSES ⚫ Most of the spinal nerves are organized into 3 major plexuses where neurons of several spinal nerves come together and intermingle ⚫ Reorganizes the neurons so that branches of nerves extending from each plexus contain neurons from different spinal segments ⚫ The 3 major plexuses are  4 MAJOR NERVES OF LUMBOSACRAL PLEXUS 5 MAJOR NERVES OF BRACHIAL Obturator nerve – innervates muscles PLEXUSES of the medial thigh Femoral nerve – innervates the anterior Axillary nerve – innervates the thigh muscles shoulder Tibial nerve – innervates posterior thigh Radial nerve – innervates the posterior muscles arm and forearm Common fibular nerve – innervates Musculocutaneous nerve – innervates muscles of the lateral thigh and leg the anterior muscles of the arm Ulnar nerve – innervates 2 anterior Sciatic nerve – tibial + common fibular forearm muscles and most of the nerve (bound together within a common intrinsic arm muscles connective tissue sheath) Median nerve – innervates most of the anterior forearm muscles and some of THE BRAIN the intrinsic hand muscles ⚫ ⚫ Brainstem ⚫ Medulla oblongata ⚫ Pons ⚫ Midbrain ⚫ Cerebellum ⚫ Diencephalon ⚫ Thalamus ⚫ Epithalamus ⚫ Hypothalamus Cerebrum BRAIN STEM  Connects the spinal cord to the remainder of the brain Information relay between cerebellum Controls several nuclei involved in vital and cerebrum Breathing body functions like heart rate, blood Swallowing pressure, and breathing Balance Consists of Chewing Medulla oblongata Salivation Pons Midbrain Mid Brain Involved with Relaying auditory signals Visual reflexes Touch Crania Eye movements Pupil diameter Lens shape Regulation of body movement (substancia nigra) GASLOW COMA SCALE MEDULLA OBLONGATA Involved in GAG REFLEX Heart rate regulation Control of blood vessel diameter Breathing Swallowing Vomiting Coughing Sneezing Balance Coordination Conscious control of skeletal muscles Pons JAW JERK REFLEX Involved in  the cerebrum Thalamus Epithalamus Hypothalamus Attached to the brainstem (Pons) by large THALAMUS connections called cerebellar peduncles Involved in Maintaining balance Muscle tone Coordinating fine motor movement Learning motor skills (in partnership with the cerebrum) DIENCEPHALON Part of the brain between the brainstem and  thirst Sexual pleasure Rage Fear Relaxation after meals Largest part of the diencephalon Most sensory inputs that ascend through the spinal cord and brainstem projects to the thalamus, where ascending neurons synapse with thalamic neurons The thalamus influences mood and registers an unlocalized, uncomfortable perception of pain EPITHALAMUS Small area superior and posterior to the thalamus Consists of a few small nuclei involved in emotional and visceral response to odors plus the pineal gland The pineal gland influences the onset of puberty CEREBRUM HYPOTHALAMUS Largest part of the brain Most inferior part of the diencephalon Plays a major role in controlling the Frontal lobe – important in the control of secretion of hormones from the pituitary voluntary motor functions, motivation, gland aggression, mood, and olfactory (smell) Involved in perception Parietal lobe – principal center for receiving Body temperature and consciously perceiving most sensory Hunger information Occipital lobe – functions in receiving and perceiving visual input Temporal lobe – involved in olfactory and auditory sensations and plays an important role in memory, also involved in abstract thought and judgment Insula – “hidden” deep within the lateral fissure (involved with the sense of taste) BLOOD SUPPLY OF THE BRAIN There are important signs of a stroke The brain is very vulnerable to that we should be aware of and watch compromises in blood supply out for The blood supply to the brain is divided The more quickly the patient receives into anterior and posterior segments treatment, the better the prognosis, as a stroke left untreated for too long can The 2 main arteries that supply blood to result in permanent brain damage the brain are Some common signs and symptoms difficulty walking 1. The internal carotid arteries dizziness (anterior portion) loss of balance and coordination 2. The vertebral arteries (posterior difficulty speaking or brain and brainstem) understanding others who are STROKE speaking numbness or paralysis in the Stroke is when blood flow to an organ face, leg, or arm, most likely on stops either by blockage (bara) or just one side of the body rupture (putok) of a blood vessel blurred or darkened vision a sudden headache, especially Stroke to the brain is referred to as when accompanied by nausea, Cerebrovascular Accident (CVA), of vomiting, or dizziness which there are 2 types Prevention Hemorrhagic CVA – due to rupture of blood vessels Maintain normal blood pressure supplying the brain (pumutok Limit saturated fat, transfat, and ang ugat sa utak) cholesterol intake Refrain from smoking, and drink Ischemic CVA – due to alcohol in moderation blockage of blood vessels Control diabetes supplying the brain (nagbara ang Maintain a healthy weight ugat sa utak)  Get regular exercise Reticulospinal – Posture Eat a diet rich in vegetables and adjustment fruits Vestibulospinal – Posture and balance SENSORY FUNCTIONS Tectospinal – movement in response to visual reflexes Sensory input to the brainstem and diencephalon helps maintain PLANTAR REFLEX/ BABINSKI TEST homeostasis Three possible responses to the test Sensory input to the cerebrum and 1. Flexor: the toes curve down and cerebellum keeps us informed about our inwards, and the foot inverts; this environment is the response seen in healthy The spinal cord and brainstem contain a adults. number of ascending or sensory tracts 2. Indifferent: there is no that transmit information via action response. potentials from the periphery to various 3. Extensor: the hallux dorsiflexes, parts of the brain and the other toes fan out; this is Babinski's sign, which indicates damage to the central nervous system if elicited in an adult, but normal reflex if elicited in infants ASCENDING TRACTS DESCENDING TRACTS Spinothalamic tract – pain and Crossover of axons in the brainstem or temperature sense spinal cord are typical of descending Dorsal column – touch, position, pathways pressure sense The left side of the brain controls the Spinocerebellar tract – body position skeletal muscles on the right side of the sense body and vice versa Ascending tracts typically cross from BASAL NUCEI one other side of the body to the other in Group of functionally-related nuclei the spinal cord or brainstem important in planning, organizing, and coordinating motor movements DESCENDING TRACTS Two primary nuclei Corpus striatum – deep within Direct the cerebrum Lateral Corticospinal tract – Substancia nigra – in the skilled movements midbrain Anterior Corticospinal tract – trunk muscle movement CEREBELLUM Indirect Rubrospinal – coordination of movement  Attached to the brainstem (Pons) via the ability to impart emotional inflection to cerebellar peduncles what They say Involved in maintaining balance and muscle tone and coordinating fine motor LEFT HEMISPHERE FUNCTIONS movement Function inhibited by alcohol Receives somatic sensory signals from, and Along with the cerebrum, is involved controls muscles on, the right side of the with learning new skills body. TEST FOR CEREBELLAR FUNCTION Reasoning. Numerical and scientific skills. Alternating pronation – supination test (APST) Ability to use and understand sign Finger to nose test (FTNT) language. SPEECH AREA OF THE CEREBRAL Spoken and written language. CORTEX Persons with damage in the left hemisphere often exhibit aphasia Sensory speech area in the parietal lobe (Wernicke area) - functions in understanding and formulating coherent speech Motor speech area in the frontal lobe (Broca area) – controls the movement LIMBIC SYSTEM AND EMOTIONS necessary for speech Involves the olfactory cortex and certain RIGHT HEMISPHERE FUNCTIONS deep cortical regions and nuclei of the cerebrum and the diencephalon Receives somatic sensory signals from, and The limbic system influences long-term controls muscles on, the left side of the declarative memory, emotions, visceral body. responses to emotions, motivation, and Musical and artistic awareness. mood Space and pattern perception. Lesions of the limbic system can result Recognition of faces and emotional content in voracious appetite, increased (often of facial expressions. perverse) sexual activity, and docility Generating emotional content of language. (loss of normal fear and anger Generating mental images to compare responses) spatial relationships. Identifying and discriminating among odors. MENINGES ⚫ Patients with damage in right hemisphere regions that correspond to Broca's and Connective tissues that surround and ⚫ Wernicke's areas in the left hemisphere protect the spinal cord and the brain ⚫ speak in a monotonous voice, having lost Dura mater Archnoid mater  ⚫ Pia mater ⚫ Epidural space – between ⚫ vertebrae and dura mater Subdural space – between dura ⚫ mater and arachnoid mater Subarachnoid space – between arachnoid mater and pia mater CEREBRO SPINAL FLUID Produced by the choriod plexuses, specialized structures made of ependymal cells, which are located in the ventricles THE CRANIAL NERVES Fills the brain ventricles, central canal of the spinal cord, and the subarachnoid The cranial nerves are 12 pairs space of nerves that can be seen on the Arachnoid granulations penetrate the inferior surface of the brain superior sagittal sinus, a dural venous Some of these cranial nerves carry sinus in the longitudinal fissure, through sensory information from the organs to which the CSF passes from the the brain subarachnoid space into the blood Other cranial nerves control voluntary muscles of the face, head, and neck Other cranial nerves are connected to smooth muscles, glands or internal organs such as the heart and lungs BELLS PALSY VS STROKE The forehead receives motor innervation from both hemispheres of the cerebral If you have a patient come in cortex complaining of new or acute onset of unilateral facial paralysis without any A stroke that compromises motor other sensory or motor deficits innervation of the face would therefore determine which parts of the face are only result in paralysis of the lower half affected of the face - the forehead still receiving innervation from the unaffected Have the patient attempt to raise both hemisphere eyebrows as if surprised. Then have the patient smile In Bell's Palsy, the inflammation of the facial nerve interrupts the innervation If they cannot raise their eyebrows and after the motor commands from both cannot move the lower portion of their hemispheres have joined, so that the face on one side (full half or face) they forehead is paralyzed have Bell's palsy and should be given steroids +/- antivirals If the lower portion of the face is paralyzed but the eyebrows rise symmetrically, then you have to be concerned for a stroke and should get imaging and further consideration of treatment (depending on time of presentation and cause) AUTONOMIC NERVOUS SYSTEM the part of the nervous system responsible for control of the bodily functions not consciously directed, such as breathing, heart rate, digestive processes, etc Has two divisions 1. Sympathetic autonomic nervous system 2. Parasympathetic autonomic nervous system AUTONOMIC NERVOUS SYSTEM VS SOMATIC MOTOR NERVOUS SYSTEM Usually in somatic motor neurons, axons from the CNS extend uninterrupted to the effectors (neuron na may super habang axon) In the autonomic nervous system, axons SYMPATHETIC AUTONOMIC NERVOUS from the CNS do not extend all the way SYSTEM from the CNS to the target tissues Regulates “Fight or flight” response two extra neurons are involved Yung unang neuron, from the brain Preganglionic cell bodies are in the Yung ikalawang neuron, from the autonomic lateral horn of the spinal cord gray ganglia matter between T1 and L2 Ang tawag sa unang neuron preganglionic Main function is to activate physiologic neuron changes that prepares the body for combat/escape Ang tawag sa ikalawang neuron, post-ganglionic neuron AUTONOMIC NERVOUS SYSTEM COCAINE Regulates “Rest and digest” response Commonly snorted, inhaled as smoke, or dissolved and injected into a vein Preganglionic cell bodies are located either within the brainstem nuclei (CN Signs of use may include fast heart rate, III, VII, IX, X) or within the lateral part of sweating, and large pupils. High doses the central gray matter of the spinal cord can result in very high blood pressure between S2 to S4 or body temperature Kaya pagkakain mo tamad na tamad ka Effects begin within seconds to minutes gumalaw kasi activated ng kain ang of use and last between five and ninety parasympathetic ANS mo minutes Cocaine acts by inhibiting the reuptake of serotonin, norepinephrine, and dopamine METAMPHETAMINE HYDROCHLORIDE Low to moderate doses methamphetamine can elevate mood, increase alertness, concentration and energy in fatigued individuals, reduce appetite, and promote weight loss Relatively high doses can induce psychosis, breakdown of skeletal muscle, seizures, and bleeding in the brain Chronic high-dose use can precipitate unpredictable and rapid mood swings, psychosis (paranoia, hallucinations, deliriu m, and delusions) and violent behavior Methamphetamine's ability to increase energy has been reported to lift mood and increase sexual desire to  such an extent that users are able to MARIJUANA engage in sexual activity continuously for several days Also known as Cannabis Methamphetamine is known to possess The main psychoactive part of cannabis a high addiction liability and is tetrahydrocannabinol (THC) high dependence liability (high likelihood the immediate desired effects from that withdrawal symptoms will occur consuming cannabis include relaxation when methamphetamine use ceases) and euphoria, a general alteration of conscious perception, increased Heavy recreational use of awareness of sensation, methamphetamine may lead to increased libido and distortions in the a post-acute-withdrawal syndrome, perception of time and space which can persist for months beyond the typical withdrawal period At higher doses, effects can include altered body image, auditory and/or Methamphetamine is neurotoxic to visual illusions, hallucinations and ataxia human midbrain dopaminergic neurons In some cases, cannabis can lead It has also been shown to to dissociative states such damage serotonin neurons in the CNS. as depersonalization Damage includes adverse changes in brain structure and function, such as reductions in gray matter volume HEROIN Is an opioid used commonly as a sedative and painkiller Has euphoric effects Intravenous injection is the fastest route of drug administration, causing blood concentrations to rise the most quickly, followed by smoking, suppository (anal or vaginal insertion), insufflation (snorting), and ingestion (swallowing)