Podcast
Questions and Answers
Which of the following accurately describes facilitated diffusion?
Which of the following accurately describes facilitated diffusion?
- Movement of particles from an area of low concentration to an area of high concentration, using a transport protein.
- Movement of particles from an area of high concentration to an area of low concentration, requiring ATP.
- Movement of particles from an area of high concentration to an area of low concentration, using a transport protein. (correct)
- Movement of particles from an area of low concentration to an area of high concentration, requiring ATP.
A negative feedback loop always amplifies the initial change in a system.
A negative feedback loop always amplifies the initial change in a system.
False (B)
What is the primary function of the sodium-potassium pump?
What is the primary function of the sodium-potassium pump?
To actively transport 3 sodium ions out of the cell and 2 potassium ions into the cell.
The central nervous system (CNS) is composed of the brain and the _______.
The central nervous system (CNS) is composed of the brain and the _______.
Match the following neuron types with their function:
Match the following neuron types with their function:
Which of the following best describes the function of neuroglia?
Which of the following best describes the function of neuroglia?
The axon hillock is the site where neurotransmitters are released.
The axon hillock is the site where neurotransmitters are released.
What is the role of myelin sheaths around axons?
What is the role of myelin sheaths around axons?
A synapse is the site of communication between two neurons or between a neuron and another _______.
A synapse is the site of communication between two neurons or between a neuron and another _______.
Match the neuron type with the correct description:
Match the neuron type with the correct description:
Which type of neuroglia cell maintains the blood-brain barrier?
Which type of neuroglia cell maintains the blood-brain barrier?
Neurotransmitters are released from the postsynaptic membrane.
Neurotransmitters are released from the postsynaptic membrane.
What is the resting potential of a neuron, and what factors contribute to it?
What is the resting potential of a neuron, and what factors contribute to it?
_______ is a temporary, localized change in the resting potential that can lead to an action potential.
_______ is a temporary, localized change in the resting potential that can lead to an action potential.
Match the type of ion channel with its activation trigger:
Match the type of ion channel with its activation trigger:
Which phase of the action potential involves the closing of voltage-gated Na+ channels and the opening of voltage-gated K+ channels?
Which phase of the action potential involves the closing of voltage-gated Na+ channels and the opening of voltage-gated K+ channels?
The all-or-none principle states that the strength of an action potential is proportional to the strength of the stimulus.
The all-or-none principle states that the strength of an action potential is proportional to the strength of the stimulus.
What role does the Na+/K+ ATPase play in the action potential?
What role does the Na+/K+ ATPase play in the action potential?
In myelinated axons, action potentials propagate via _______, which involves the jumping of the action potential from node to node.
In myelinated axons, action potentials propagate via _______, which involves the jumping of the action potential from node to node.
Match the disease or condition with its effect on nerve function:
Match the disease or condition with its effect on nerve function:
What is the primary function of the cerebrospinal fluid (CSF)?
What is the primary function of the cerebrospinal fluid (CSF)?
The blood-brain barrier allows all substances to freely pass from the bloodstream into the brain.
The blood-brain barrier allows all substances to freely pass from the bloodstream into the brain.
List the three main components of the brainstem.
List the three main components of the brainstem.
The _______ monitors and coordinates movement, ensuring smooth and balanced motor functions.
The _______ monitors and coordinates movement, ensuring smooth and balanced motor functions.
Match the brain region with its primary function:
Match the brain region with its primary function:
Which lobe of the cerebrum is primarily responsible for visual processing?
Which lobe of the cerebrum is primarily responsible for visual processing?
The hippocampus is primarily involved in motor coordination.
The hippocampus is primarily involved in motor coordination.
What is the function of the corpus callosum?
What is the function of the corpus callosum?
The _______ nervous system is responsible for the 'fight or flight' response, while the _______ nervous system is responsible for 'rest and digest' functions.
The _______ nervous system is responsible for the 'fight or flight' response, while the _______ nervous system is responsible for 'rest and digest' functions.
Match the plexus with its area of innervation:
Match the plexus with its area of innervation:
Which nerve from the cervical plexus is critical for breathing?
Which nerve from the cervical plexus is critical for breathing?
A reflex arc always involves the brain in processing the response.
A reflex arc always involves the brain in processing the response.
What are the five components of a reflex arc?
What are the five components of a reflex arc?
_______ are sensory receptors that detect pain.
_______ are sensory receptors that detect pain.
Match the term to its definition:
Match the term to its definition:
Which cranial nerve is responsible for taste sensations in the posterior 1/3 of the tongue?
Which cranial nerve is responsible for taste sensations in the posterior 1/3 of the tongue?
Rods are responsible for color vision, while cones are responsible for vision in dim light.
Rods are responsible for color vision, while cones are responsible for vision in dim light.
What is the function of the auditory tube?
What is the function of the auditory tube?
The _______ in the semicircular canals are responsible for detecting dynamic equilibrium.
The _______ in the semicircular canals are responsible for detecting dynamic equilibrium.
Match the muscle fiber type with the activity it primarily supports:
Match the muscle fiber type with the activity it primarily supports:
Flashcards
Ligands
Ligands
Chemical signals that bind to receptors.
Receptors
Receptors
Receivers/proteins that bind to chemical signals.
Facilitated diffusion
Facilitated diffusion
Movement from high to low concentration, using a transport protein.
Active transport
Active transport
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Diffusion
Diffusion
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Negative feedback loop
Negative feedback loop
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Ion
Ion
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Sodium-potassium pump
Sodium-potassium pump
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Sensory function
Sensory function
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Integration
Integration
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Motor function
Motor function
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CNS (Central Nervous System)
CNS (Central Nervous System)
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PNS (Peripheral Nervous System)
PNS (Peripheral Nervous System)
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Afferent division
Afferent division
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Efferent division
Efferent division
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Neurons
Neurons
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Neuroglia
Neuroglia
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Cell body (soma)
Cell body (soma)
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Dendrites
Dendrites
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Axon hillock
Axon hillock
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Axon terminal
Axon terminal
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Axon
Axon
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Synapse
Synapse
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Presynaptic cell
Presynaptic cell
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Postsynaptic cell
Postsynaptic cell
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Synaptic cleft
Synaptic cleft
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Sensory neurons
Sensory neurons
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Interneurons
Interneurons
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Astrocytes
Astrocytes
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Oligodendrocytes
Oligodendrocytes
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Microglia
Microglia
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Schwann cells
Schwann cells
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Node of Ranvier
Node of Ranvier
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Neurotransmitters
Neurotransmitters
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Graded potential
Graded potential
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Action potential
Action potential
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Hyperpolarization
Hyperpolarization
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Depolarization
Depolarization
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All-or-none principle
All-or-none principle
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Inactivation of Na+ channels
Inactivation of Na+ channels
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Study Notes
- Ligands are chemical signals that bind to receptors.
- Receptors are proteins that bind to ligands, acting as receivers of these signals.
- Facilitated diffusion involves movement from an area of high concentration to low concentration with the help of a transport protein.
- Active transport moves substances from an area of low concentration to high concentration, requiring ATP.
- Diffusion is the movement of particles from high to low concentration.
- A negative feedback loop responds to a change by returning a system to its original state or slowing down the change.
- An ion is a charged atom or molecule.
- Sodium ions naturally flow into the cell.
- Potassium ions naturally flow out of the cell.
- The sodium-potassium pump actively transports 3 sodium ions out and 2 potassium ions into the cell, using ATP.
- The nervous tissue's three basic functions are sensory function, integration, and motor function.
- Sensory function involves detecting stimuli and converting them into nerve impulses for the CNS.
- Integration is when the CNS compiles nerve impulses from different body parts and generates a response.
- Motor function allows the nervous system to generate signals from the CNS to effectors.
- An efferent neuron is a motor neuron.
- The CNS consists of the spinal cord and brain, which process and coordinate information.
- The functions of the CNS include sensory data processing, motor command generation, and higher brain functions.
- An afferent neuron is a sensory neuron.
- The PNS is made up of cranial and spinal nerves.
- The afferent division carries sensory information from the PNS to the CNS.
- Sensory refers to detecting stimuli in peripheral neurons/proteins.
- The efferent division carries motor commands from the CNS to the PNS.
- Receptors detect changes or respond to stimuli.
- Examples of receptors include neurons, specialized cells, and complex sensory organs.
- Effectors respond to efferent signals.
- Examples of effectors are cells and organs.
- Neural tissue is made of neurons and neuroglia.
- Neurons are cells that send and receive signals.
- Neuroglia are cells that support and protect neurons.
- There are more neuroglia than neurons, in a 10:1 ratio.
- A neuron is the basic functional unit of the nervous system.
- A cell body (soma) is responsible for receiving, integrating, and sending nerve impulses.
- Cell bodies contain a large nucleus/nucleolus, ribosomes, mitochondria, Rough ER, and a cytoskeleton.
- Dendrites are branched extensions that receive signals from other neurons.
- The axon hillock is where action potentials are generated.
- The axon terminal releases neurotransmitters.
- Nissl bodies are dense areas of rough ER and free ribosomes.
- An axon carries electrical signals to the target cell.
- Dendrites receive information from other neurons.
- A synapse is a site of communication between two neurons or between a neuron and another effector.
- A postsynaptic cell receives message (neurons, muscles, and glands).
- A presynaptic cell sends message (releases chemical messenger or communicates via ions).
- The synaptic cleft is the small gap between the presynaptic and postsynaptic membranes.
- Anaxonic neurons have dendrites and axons that look alike.
- Anaxonic neurons are found in the CNS and special sense organs.
- Bipolar neurons have one dendrite and one axon with the cell body in between.
- Bipolar neurons relay information for sight, smell, and hearing.
- Pseudounipolar neurons have a cell body that lies off to one side.
- Pseudounipolar neurons are found in the sensory neurons of the PNS.
- Multipolar neurons have multiple dendrites and one axon.
- Multipolar neurons are found in the CNS and include all skeletal muscle motor neurons.
- Sensory neurons monitor the internal environment and effects of the external environment, sending information afferently to the CNS.
- Pseudopolar neurons are sensitive to vibration, pressure in the skin, pain, and light touch.
- Nociceptors are pain receptors.
- Sensory neurons are found in the dermal tissue of the skin.
- Interneurons are located in the brain and spinal cord between sensory and motor neurons.
- Interneurons are involved in memory, planning, and learning.
- Neuroglia preserve the physical and biochemical structure of neural tissue.
- Neuroglia are essential for neuron function and survival.
- The four types of neuroglia in the CNS are astrocytes, oligodendrocytes, microglia, and ependymal cells.
- Ependymal cells line the central canal of the spinal cord and ventricles of the brain.
- Ependymal cells secrete CSF, which must be kept at a constant volume.
- Ependymal cells circulate CSF using cilia or microvilli.
- Ependymal cells monitor CSF to maintain its constant volume.
- Ependymal cells have stem cells for repair.
- Astrocytes maintain the blood-brain barrier and isolate the CNS.
- Astrocytes repair damaged neural tissue, forming scar tissue.
- Astrocytes guide neuron development.
- Astrocytes are the most abundant glial cells.
- Oligodendrocytes wrap around axons to form myelin sheaths.
- Microglia migrate through neural tissue, cleaning up cellular debris, waste, and pathogens.
- White matter is white because of the myelin sheaths.
- The two types of neuroglia in the PNS are Schwann cells and satellite cells.
- Satellite cells surround ganglia to regulate the environment around the neuron.
- Schwann cells form myelin sheaths around peripheral axons.
- Neurilemma is a layer of cells that encases many axons.
- Schwann cells are not continuous.
- Node of Ranvier is a small gap between myelinated segments where axonal membrane is exposed.
- Myelination is a fatty sheath around the axons of a neuron.
- Myelinated sheaths increase the speed of action potentials, communication speed, prevent loss of ions, and provide insulation.
- Gray matter is gray because it has unmyelinated areas.
- Axodendritic synapses occur from axon to dendrite.
- Axosomatic synapses occur from axon to cell body.
- Dendrodendritic synapses occur from dendrite to dendrite.
- Axoaxonic synapses occur from axon to axon.
- Neurotransmitters are chemical messengers.
- Neurotransmitters are released from the presynaptic membrane.
- Neurotransmitters bind to proteins on the postsynaptic membrane, affecting its receptors.
- Enzymes break down neurotransmitters, which is necessary for proper function.
- Neurotransmitters are reassembled in the synaptic knob.
- Electrical synapses are fast and bi-directional.
- Chemical synapses are slow and unidirectional.
- Electrical signals move through gap junctions via ion movement.
- Chemical signals move from the presynaptic cell to the postsynaptic cell.
- Acetylcholine (ACh) decreases heart rate in the heart (inhibitory).
- Acetylcholine (ACh) causes muscle contraction in skeletal muscle (stimulatory).
- Electrical signals can only be excitatory (always resulting in an action potential).
- Chemical signals can be either excitatory or inhibitory, depending on the ions and chemical messengers involved.
- The resting potential of a cell is -70 mV.
- Neurons are electrically excitable due to voltage differences across their membrane.
- The two types of electrical signals are graded potentials and action potentials.
- Ions flow across the cell membrane through ion channels.
- Ion channels are found in the nervous system and plasma membrane of all cells.
- All plasma membranes produce electrical signals through ion movement.
- The three types of potentials are resting, graded, and action.
- Resting potential is the transmembrane potential of a resting cell.
- Graded potential is a temporary, localized change in resting potential.
- Action potential is an electrical impulse going down axons.
- An action potential is produced by a graded potential.
- An action potential propagates along the surface of the axon to the synapse.
- Resting potential exists because the concentration of ions is different inside and outside the cell.
- Action potentials travel long distances.
- Graded potentials travel short distances.
- A cell is negative due to negatively charged organic phosphate and protein inside.
- Cytosol is full of K+ and P-.
- The Na+/K+ pump removes Na+ as fast as it leaks in.
- Hyperpolarization (more negative from rest) can be caused by:
- Increased permeability to Cl-, causing Cl- to rush in.
- Increased permeability to K+, causing K+ to rush out.
- Depolarization (more positive from rest) is caused by:
- Increased permeability to Na+, causing Na+ to rush in.
- Decreased permeability to K+, causing K+ to stay in.
- Graded means varying in amplitude (size).
- The amount of change in voltage depends on the amount of ions moving in or out.
- Graded potentials occur most often in dendrites and the cell body.
- The 3 different types of channels are:
- Voltage-gated
- Mechanically-gated
- Ligand-gated
- Voltage-gated channels respond to a change in charge.
- Mechanically gated channels respond to a physical distortion.
- Ligand gated channels respond to chemicals/chemical messengers.
- Four overall steps to an action potential:
- Cell reaches threshold
- Depolarization
- Repolarization
- Hyperpolarization
- During an action potential, voltage-gated Na+ and K+ channels open in sequence.
- The all-or-none principle states that if a stimulus reaches threshold, the action potential is always the same.
- Threshold is reached at the axon hillock.
- Depolarization leads to action potentials.
- Voltage-gated channels are at the axon hillock.
- The first step of action potential is a graded potential at dendrites and cell body leads to a depolarization.
- The second step of action potential is that if depolarization is strong enough, it reaches the Axon Hillock.
- The third step of action potential is reaching threshold is = a strong enough voltage change to open voltage-gated (VG) Na+ channels, which is the Depolarization phase of the action potential.
- The fourth step of action potential is that voltage-gated Na+ channels close automatically after some time, which is inactivation of Na+ channels, which is important to allow forward movement of the action potential.
- The fifth step of action potential is that voltage-gated K+ channels are open, so K+ rushes out, which is repolarization phase of AP.
- The sixth step of action potential is that VG K+ channels close slowly which gets a brief period of hyperpolarization.
- The seventh step of action potential is that the Na+, K+ ATPase helps to bring everything to rest.
- K+ is 50-100x more leaky than Na+.
- -55 mV is threshold.
- +30 mV is peak voltage (depolarization to repolarization).
- Less than -70 mV is hyperpolarization.
- The two methods of propagating action potentials are:
- Continuous propagation
- Saltatory propagation
- Propagation = movement.
- Continuous propagation occurs in unmyelinated axons.
- Saltatory propagation occurs in myelinated axons.
- Unmyelinated axons use many voltage-gated Na+ channels in close proximity to one another/very close together.
- Myelinated axons use passive current to spread further down the axon until it reaches the nodes of Ranvier.
- Passive conduction is the movement of an action potential down the length of an unmyelinated axon.
- Unidirectional conduction of an action potential is due to the transient inactivation of voltage-gated Na+ channels.
- Na+ channels are found at the nodes of Ranvier.
- Poliomyelitis (polio) is an infection that impacts the CNS and especially the spinal cord; can result in deformity and paralysis.
- There is no cure for polio, but it can be prevented by a vaccine.
- The path of rabies includes:
- Entering muscle cells
- Passing into motor neurons at the neuromuscular junction
- Traveling the length of the axon by retrograde axonal transport until reaching the spinal cord.
- Examples of viruses that affect electrical signals are herpes, rabies, and tetanus.
- Tetanus toxin binds to inhibitory interneurons, preventing the release of glycine and relaxation of muscle.
- Multiple sclerosis (MS) is an autoimmune disorder where the body attacks myelin sheaths within the CNS.
- Symptoms of losing myelinated sheaths include alterations in behavior and cognitive abilities, and motor dysfunction, including paralysis.
- Venomous arthropods include spiders and scorpions.
- A neurotoxin is a poison that attacks the nervous system, causing blindness, paralysis, or suffocation.
- Treatment and prognosis for a neurotoxin bite include antivenin to block the toxin.
- The CNS, made up of the brain and spinal cord, integrates and processes nervous information.
- The PNS, made up of nerves and ganglia, sends information to and receives information from the CNS.
- The brain is a soft, whitish-gray organ that is anatomically continuous with the spinal cord, that controls most of the body's functions directly or indirectly.
- The brain resides in the cranial cavity.
- Ventricles are the brain's internal cavities.
- The ventricles in the brain are filled with cerebrospinal fluid (CSF).
- The brain weighs about 3 pounds.
- The brain receives about 20% of total blood flow, reflecting its high requirements for oxygen, glucose, and nutrients.
- The vertebral cavity encloses the spinal cord to protect it.
- The vertebral cavity ends between the first and second lumbar vertebrae.
- The central canal is an internal cavity within the spinal cord.
- The central canal is continuous with the brain's ventricles.
- The central canal is filled with cerebrospinal fluid.
- Four divisions of the brain:
- Cerebrum
- Diencephalon
- Cerebellum
- Brainstem
- The cerebrum performs higher mental functions, interprets sensory stimuli, plans and initiates movement.
- The diencephalon processes, integrates, and relays information, maintains homeostasis, and regulates biological rhythms.
- The cerebellum monitors and coordinates movement.
- The brainstem maintains homeostasis, controls certain reflexes, monitors movement, and integrates and relays information.
- The development of the nervous system begins with a thickening of the ectoderm.
- The neural plate is the outermost tissue that leads to the development of the neural tube in the embryo.
- The CNS begins as a hollow neural tube.
- The anterior end of the neural tube gives rise to the primary brain vesicles.
- The 3 swellings of brain at 3 weeks are forebrain (prosencephalon), midbrain (mesencephalon), and hindbrain (rhombencephalon).
- The 5 swellings of brain at 5 weeks are (pros: tel & di, mesen: unchanged, rhomb: met, mye).
- The prosencephalon becomes the telencephalon and diencephalon.
- The mesencephalon remains unchanged through development.
- The rhombencephalon becomes the metencephalon and myelencephalon.
- The neural tube is the precursor to forebrain, midbrain, and hindbrain.
- The forebrain (prosencephalon) is the precursor to telencephalon and diencephalon.
- The primary mesencephalon is the precursor to the mesencephalon.
- The hindbrain (rhombencephalon) is the precursor to metencephalon and myelencephalon.
- The telencephalon is the precursor of the cerebrum.
- The secondary diencephalon is the precursor of the diencephalon.
- The mesencephalon is the precursor of the midbrain.
- The metencephalon is the precursor to the pons and cerebellum.
- The myelencephalon is the precursor to the medulla oblongata.
- The brain is protected by cranial bones, cranial meninges, cerebrospinal fluid, and the blood-brain barrier.
- Meninges are made of connective tissue.
- The cranial meninges are the pia mater, arachnoid, and dura mater.
- The cranial dura mater is made of 2 layers.
- The protection layers of the brain, from superficial to deep, are:
- Epidural space
- Dura mater
- Subdural space
- Arachnoid mater
- Subarachnoid space
- Pia mater
- The dura mater is made of dense irregular connective tissue.
- The dura mater is fused to the periosteum lining the cranial bones.
- The subdural space is a serous fluid-filled space found deep to the dura mater and superficial to the arachnoid mater.
- The subdural space houses the veins that drain blood from the brain.
- The arachnoid mater is a netlike membrane covering.
- CSF flows under the arachnoid in the subarachnoid space.
- The subarachnoid space contains CSF and major blood vessels of the brain.
- The pia mater is the inner most layer, highly vascular, tight to the convolutions of the brain and spinal cord.
- Pia mater allows blood vessels to pass through and nourish the brain.
- Pia mater allows substances to move between two fluid compartments because it is permeable.
- Dural sinuses are venous channels that drain CSF and deoxygenated blood from the brain's many veins.
- Meningitis is an infection of the meninges in the subarachnoid space, causing inflammation.
- The purpose of CSF is to protect the brain and spinal cord against chemical and physical injuries.
- The function of CSF is to carry oxygen, glucose, and other important substances from the blood to nervous tissue cells.
- The ventricles of the brain contain CSF.
- The choroid plexus makes CSF to keep it at a constant volume.
- The Blood Brain Barrier (BBB) is a selective barrier that prevents bacteria and large molecules from entering the brain.
- Blood flows to and back from the brain via the vertebral and carotid arteries.
- Interruption of oxygen supply results in weakening, permanent damage, or death of brain cells.
- Glucose deficiency produces mental confusion, dizziness, convulsions, and unconsciousness.
- The brain stem is made up of:
- Midbrain
- Pons
- Medulla
- Astrocytes make the BBB.
- The medulla oblongata regulates:
- Heart rate
- Respiratory rate
- Vasoconstriction
- Swallowing
- Coughing
- Vomiting
- Sneezing
- Hiccupping
- Vasoconstriction reduces blood flow
- The pons:
- Relays nerve impulses related to voluntary skeletal muscle movements
- Sensory roles in hearing, equilibrium and taste
- Motor roles in eye movement, facial expressions, chewing, swallowing, secretion of saliva and tears
- The pneumotaxic and apneustic areas control respiration.
- The midbrain:
- Conveys motor impulses from the cerebrum to the cerebellum and spinal cord
- Sends sensory impulses from the spinal cord to the thalamus
- Regulates auditory and visual reflexes
- The reticular formation is a set of interconnected nuclei that are located throughout the brain stem.
- Central nuclei function in sleep, pain transmission, and mood.
- Nuclei surrounding central nuclei serve motor functions for both skeletal muscles and the autonomic nervous system.
- Other nuclei are instrumental in homeostasis of breathing and blood pressure.
- Lateral nuclei play a role in sensation and in alertness and activity levels of the cerebral cortex.
- The cerebellum is made up of two hemispheres and a central vermis.
- Cerebellum functions to maintain normal muscle tone, posture, and balance.
- The diencephalon is made up of thalamus, hypothalamus, and epithalamus.
- The nuclei do in the thalamus serves as relay stations for all sensory impulses to the cerebral cortex.
- The thalamus nuclei is the main entry route of sensory data into the cerebral cortex.
- The epithalamus contains the pineal gland and habenular nuclei.
- The pineal gland secretes melatonin.
- The habenular nuclei does visceral and emotional responses to odors.
- The cerebrum allows ability to read, write and speak, compose music, remember the past, plan for the future.
- The cerebral cortex is the outer rim of the cerebrum made of gray matter that has billions of neurons.
- White matter is composed of tracts of neurons that connect parts of the brain to each other and the spinal cord.
- The longitudinal fissure separates the left and right hemispheres.
- The corpus callosum allows for communication between the two hemispheres of the brain.
- The 5 divisions of the cerebrum are:
- Frontal
- Parietal
- Temporal
- Occipital
- Insula
- The insula is in charge of awareness, emotional response, empathy, and taste.
- The frontal lobe function includes reasoning, planning, parts of speech, emotions, problem solving.
- The parietal lobe function includes orientation, recognition, perception of stimuli.
- The temporal lobe function includes perception and recognition of auditory stimuli, memory, and speech.
- The occipital lobe function is visual processing.
- The limbic system is located just under the cerebrum.
- The limbic system is made up of hypothalamus, hippocampus, and amygdala.
- The function of the limbic system is memory, learning, emotion, and behavior.
- The hippocampus turns short-term memories into long-term memories.
- Damage to the hippocampus prevents building new memories.
- The amygdala is involved in fear and sorts and codes memories based on how they are emotionally perceived.
- Basal nuclei regulates unconscious movements.
- The spinal cord relays and processes information.
- The brain's meninges pass through the foramen magnum.
- The 3 spinal meninges:
- Dura mater (1 layer)
- Arachnoid mater
- Pia mater
- Epidural anesthesia is inserted into the epidural space to numb.
- A lumbar puncture is inserted in the subarachnoid space between L4 and L5.
- Spinal nerves carry sensory and motor impulses to and from the spinal cord.
- Neuron cell bodies found in the anterior horn do somatic motor functions.
- Neuron cell bodies in the posterior horn process incoming somatic and visceral sensory information.
- Neuron cell bodies in the lateral horn control of viscera via the autonomic nervous system.
- Spinal white matter contains axons of neurons that travel to and from the brain.
- Ganglia are dense groups of nerve-cell bodies, a cluster of neural bodies outside the CNS.
- Nerves are bundles collections of axons.
- Endoneurium a sheath of connective tissue that encloses each nerve cell.
- Perineurium surrounds fascicles.
- Epineurium most outer layer, surrounds nerve.
- The somatic nervous system consists of sensory neurons and somatic motor neurons.
- Sensory neurons in the somatic nervous system convey sensory info from somatic receptors to the CNS.
- Somatic motor neurons conduct impulses from the CNS to skeletal muscle.
- The autonomic nervous system consists of sensory neurons and autonomic motor neurons.
- Sensory neurons in the autonomic nervous system convey sensory info from autonomic receptors to the CNS.
- Autonomic motor neurons conducts impulses from the CNS to smooth muscles, cardiac muscle and glands (involuntary).
- The two major branches of the motor autonomic nervous system are sympathetic and parasympathetic.
- The sympathetic nervous system is the "fight or flight" division.
- The parasympathetic nervous system is the "rest and digest" division.
- The enteric nervous system consists of neurons in the enteric plexus of the gut that monitor stretch and chemical changes within GI tract.
- The saying for the cranial nerves is, "OhOhOhToTouchAndFeelVirginGirlVaginaAndHymen".
- The cranial nerve function saying is, "Some Say Money Matters But My Brother Says Big Boobs Matter More".
- Sensory nerves connect the CNS to sensory receptors, muscles, and glands.
- There are 31 pairs of spinal nerves.
- 8 cervical
- 12 thoracic
- 5 lumbar
- 5 sacral
- 1 coccygeal
- Spinal nerves leave the spinal cord canal via intervertebral foramina.
- Anterior and posterior roots attach a spinal nerve to a segment of the spinal cord.
- An interneuron is a nerve cell that relays messages between nerve cells, especially in the brain and spinal cord.
- Mixed nerves are nerves carrying both sensory and motor fibers.
- The posterior root of the spinal cord contains sensory axons, with cell bodies in the posterior dorsal root ganglion.
- The anterior ventral root contains only motor axons.
- Spinal nerves divide into several branches called rami after passing intervertebral foramen.
- A nerve plexus is a network of anterior rami.
- The 4 plexuses are cervical, brachial, lumbar, and sacral.
- The cervical plexus is C1-C5.
- The cervical plexus innervates skin and muscles of the neck, head, and shoulders.
- The phrenic nerve innervates the diaphragm and is therefore critical for breathing.
- The brachial plexus is C5-C8, T1.
- The brachial plexus innervates the entire upper extremity, neck and shoulder muscles.
- The 5 major nerves in the brachial plexus are musculocutaneous (bicep), median ( flex wrist), axillary (deltoid), radial (triceps), and ulnar (forearm).
- The lumbar plexus is L1-L4, T 12.
- The lumbar plexus innervates lower abdomen, anterior and medial portions lower extremity.
- The 2 main nerves of lumbar plexus are femoral and obturator.
- The sacral plexus is L4, L5, S1-S4.
- The sacral plexus innervates the lower back, pelvis, perineum (butt and genital), dorsal and plantar surface of feet.
- Dermatomes are segments of the skin are supplied by spinal nerves that carry somatic sensory nerve impulses to the brain.
- A reflex is a fast, predictable, autonomic response to changes in the environment.
- Reflexes help maintain homeostasis.
- The spinal cord is the integrating center for spinal reflexes.
- The components of a reflex arc:
- Receptor
- Sensory neuron
- Integration center
- Motor neuron
- Effector
- Sensation is the conscious or subconscious awareness of changes in the external or internal environment.
- Perception is the conscious interpretation of sensations performed mainly by the cerebral cortex.
- Two groups for sensation are general and specific.
- General senses are somatic and visceral.
- Somatic sense: tactile, thermal, proprioceptive
- Visceral sense: pressure, chemicals, stretch, nausea, hunger, temp
- When stimulated, a receptor passes info to the CNS in form of AP along axon of sensory neuron.
- The five types of sensory receptors are:
- Chemoreceptors
- Mechanoreceptors
- Photoreceptors
- Thermoreceptors
- Nociceptors
- Mechanoreceptors are sensitive to stimuli that distort their plasma membranes.
- The three classes of mechanoreceptors are tactile receptors, baroreceptors, and proprioceptors.
- Tactile receptors provide the sensations of touch, pressure, and vibration.
- Baroreceptors detect pressure changes in the walls of blood vessels and in portions of the digestive, reproductive, and urinary tracts.
- Proprioceptors monitor the positions of joints and muscles.
- Chemoreceptors are in the carotid and aortic bodies.
- Chemoreceptors monitor pH, CO2, and O2 in arterial blood.
- CO2 build-up (not lack of oxygen) causes you to breath.
- Central thermoreceptors in the hypothalamus monitor internal temperature.
- Peripheral thermoreceptors in the dermis monitor environmental temperature.
- Nerve regeneration occurs when Schwann cells produce a regeneration tube to direct regrowth of the axon.
- CNS neurons cannot regenerate.
- Learning is the ability to acquire new information or skills through instructions or experience.
- Memory is process by which info acquired through learning is stored and retrieved.
- Short-term memory (STM)is the temporary holding of information.
- Long-term memory (LTM) has limitless capacity.
- The factors that affect transfer from STM to LTM are emotional state, rehearsal, and association.
- Sleep is a state of altered consciousness.
- The two components of sleep are non-REM and REM.
- People deprived of REM sleep become moody and depressed.
- The daily sleep requirement decreases as we age.
- Narcolepsy is attacks of sleep.
- Insomnia is the inability to sleep.
- Sleep apnea is when a person stops breathing for nearly half a minute or more.
- Six reasons sleep is important:
- Memory consolidation
- Metabolism and weight
- Safety
- Mood
- Cardiovascular health
- Disease
- Pathway for parasympathetic axons:
- Cell bodies of preganglionic motor neurons located in cranial nerves or in sacral part of spinal cord.
- Preganglioninc axons synapse in the terminal ganglia which are located close to or on the organ being innervated.
- Parasympathetic postganglionic axons travel from the terminal ganglia to the target organ.
- Use ACh and NE.
- Pathway of sympathetic nervous system starts in middle of spinal cord --> short axon synapses with sort ganglia close to spine -> 2nd neuron goes to the target cell (smooth, cardiac, gland cell).
- Only ACh
- 2 chain axons: short --> long
- There are two autonomic motor neurons in series:
- Preganglionic neuron.
- Cell body in CNS, extends to autonomic ganglion
- Postganglionic neuron
- Unmyelinated axon extends from the ganglion to the effector
- Preganglionic neuron.
- Autonomic tone is a balance between the sympathetic and parasympathetic activity.
- The ANS relies on adrenergic receptors for regulating the body without consciousness.
- Adrenergic receptors are acted upon by epinephrine and norepinephrine.
- Adrenergic receptors include alpha and beta receptors.
- When adrenergic receptors are stimulated, arteries constrict to increase BP and flow going to the heart.
- The sympathetic nervous system has short, fast neurons.
- The sympathetic nervous system activates the adrenal gland (adrenal medulla).
- After the SNS activates the adrenal gland, it releases hormones into blood.
- Cholinergic receptors are part of parasympathetic system.
- The parts of the cholinergic is nicotinic and muscarinic.
- Muscarinic receptors are both excitatory and inhibitory.
- Muscarinic receptors do not affect skeletal muscles.
- Muscarinic receptors affect exocrine glands, smooth muscle, and cardiac system.
- Autonomic nervous system, sympathetic pathways examples include, but are not limited to:
- Increase HR
- Pupil dilation
- Expand airway
- Reduce digestion
- Sweating
- Blood flow to muscles -Release glucose
- Autonomic nervous system, parasympathetic pathways examples include, but are not limited to:
- Decrease HR
- Pupil constriction
- Stimulate digestion
- Stimulate saliva and urine excretion
- The same neurotransmitter, NE, can increase heart rate and inhibit digestion by using different receptors.
- ACh is at the preganglionic synapse.
- NE is the postganglionic NT in the sympathetic nervous system.
- The sympathetic division is also called the thoracolumbar division.
- Preganglionic neurons originate in the lateral horns of thoracic and lumbar spinal cord.
- The cell bodies of preganglionic neurons are in 12 thoracic and first lumbar.
- Chromaffin cells in the adrenal medulla release NE and EPI.
- Catecholamines are hormones, such as dopamine, epinephrine, and norepinephrine.
- The adrenal gland is an endocrine gland.
- The parasympathetic nervous system (NS) uses ACh for both pre and post ganglionic neurons.
- The parasympathetic division is also called the craniosacral division.
- Cell bodies of the preganglionic neurons are in the brain stem or sacral levels of spinal cord.
- The nerves in the PNS include oculomotor, facial, glosso, and vagus (in the brain stem).
- S2-S4 makes up the pelvic nerves in the PNS.
- ACh is the only neurotransmitter in parasympathetic.
- Cholinergic fibers release Acetylcholine (ACh).
- All parasympathetic postganglionic axons release Acetylcholine (ACh).
- Adrenergic fibers release Norepinephrine (NE).
- Except, sympathetic fibers secrete ACH at sweat glands
- Epinephrine = adrenaline, norepinephrine = noradrenaline.
- Smell is a chemical sense.
- Humans have 10-100 million receptors for smell.
- The olfactory epithelium covers the inferior surface of the cribriform plate and along the superior nasal concha.
- The pathway of smell:
- Nares
- Nasal cavity
- Three concha
- Olfactory epithelium
- Through ethmoid bone (cribriform plate)
- Olfactory bulb
- Olfactory tract
- Olfactory CN I
- Primary olfactory area in cerebral cortex
- Temporal lobe
- Taste is a chemical sense.
- The 5 primary tastes are:
- Sweet
- Sour
- Salty
- Bitter
- Umami
- The three types of papillae are:
- Vallate
- Fungiform
- Foliate
- Vallate papillae are at the back of the tongue (12 of them), and have 100-300 taste buds each.
- Fungiform papilla are all over the tongue, and have 5 taste buds each.
- Foliate papillae are trenches during childhood.
- Filiform papillae are for texture and temp, and have no taste.
- Filliform papillae don't have taste buds.
- There are 10,000 taste buds on the tongue.
- The three cranial nerves involved in taste are facial CN VII, glossopharyngeal CN IX, and vagus CN X.
- The facial (CN VII) accounts for taste from 2/3 of tongue.
- The glossopharyngeal (CN IX) accounts for taste from 1/3 of tongue.
- The vagus (CN X) accounts for taste from the epiglottis and throat.
- The thalamus is a relay station for special senses.
- The pathway of taste is, "hit tongue, nerve, medulla, thalamus, cerebral cortex of parietal".
- Accessory structures of the eyes include eyelids, eyelashes, eyebrows, lacrimal apparatus, and extrinsic eye muscles.
- The conjunctiva is a delicate membrane lining the eyelids and covering the eyeball.
- The three cranial nerves that innervate the eye are oculomotor, trochlear, and abducens.
- The oculomotor (III) controls superior, inferior and medial rectus, inferior oblique muscles.
- The trochlear (IV) controls the superior oblique.
- The abducens (VI) controls the lateral rectus muscle.
- The iris regulates the amount of light that enters the eye, by controlling the size of the pupil based on autonomic reflexes.
- The pupillary dilator muscle dilates the eye in low light.
- The pupillary sphincter muscle constricts the pupil in high light.
- The retina lines posterior three-quarters of the inner layer of the eyeball.
- The retina can be viewed using an ophthalmoscope.
- The ciliary body is a thick extension of the choroid.
- The function of the ciliary body is a muscular ring for supporting the iris, focus the lens, and secrete aqueous humor.
- The optic disc is the point at which the optic nerve exits the eye.
- The blind spot is at the optic disc.
- The exact center of the retina is the macula lutea.
- The center of the macula lutea is the fovea centralis.
- Fovea centralis has the highest visual activity.
- Photoreceptors are located in the retina.
- Rods enable seeing in dim light
- Cones enable produce color vision.
- The path through the neural layer:
- Photoreceptors
- Outer synaptic layer
- Bipolar cells
- Inner synaptic layer
- Ganglion cells
- The axons of bipolar and ganglion cells exit as the optic nerve.
- Aqueous humor is clear fluid in space between the lens and cornea, for nourishment.
- Ciliary bodies make aqueous humor.
- Aqueous humor fills the anterior and posterior chambers.
- Aqueous humor drains into the scleral venous sinus (canal of Schlemm) back into blood.
- Glaucoma is caused by inadequate drainage of aqueous humor.
- Vitreous humor is clear gel substance in vitreous chamber.
- The function of vitreous humor is to maintain the shape of the eyeball and keep retina attached to choroid.
- The path of light from cornea to retina: cornea> anterior chamber> pupil> posterior chamber> lens > vitreous humor> projected onto the retina
- The ora serrata is the serrated junction between the retina and the ciliary body.
- The path of light from retina to optic nerve: retina> active rods and cones> bipolar cells> ganglion cells > converge form optic nerve.
- The cornea admits and refracts light.
- Light refracts when it passes through a transparent substance with one density into a second transparent substance with a different density. Bending occurs at the junction of the two substances.
- Path after optic nerve: optic nerve, optic chiasm> optic tract> lateral geniculate of thalamus> optic radiations> primary visual areas of occipital lobe
- Accommodation of eye is the eye's ability to focus and maintain an image on the retina, using the elastic lens and ciliary muscle.
- The ciliary body is relaxed when
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