F24 ANA 109 Unit 6 SG KEY PDF - Week 12 Nervous Signaling

ANA 109 Unit 6: The Nervous System Week 12: Nervous Signaling Name the two major structures of the Central Nervous System: Brain & Spinal Cord Describe the three basic functional components of the nervous system with regards to the maintenance of homeostasis: Sensory Function: gathering of informat...

ANA 109 Unit 6: The Nervous System Week 12: Nervous Signaling Name the two major structures of the Central Nervous System: Brain & Spinal Cord Describe the three basic functional components of the nervous system with regards to the maintenance of homeostasis: Sensory Function: gathering of information about the internal & external environments of the body Integrative Function: analysis & interpretation of the sensory stimuli + determination of appropriate response Motor Function: actions performed to carry out response to integration Label the anatomy of a standard neuron below: A: Dendrites B: Cell Body (Soma) C: Axon Hillock D: Axon E: Axon Terminals Describe the three anatomical classifications of a neuron: Multipolar: many dendrites + one axon **Most common type of neuron Bipolar: one main dendrite + one axon **Special senses use bipolar neurons relay information such as from rods/cones to retinal ganglion cells of the optic nerve to transmit visual information to the CNS Unipolar (Pseudo-unipolar): One axo-dendritic process that splits into one axon & one dendrite; Cell body adjacent to axo-dendritic process **Allows signal to bypass the cell body Describe the three functional classifications of a neuron: Sensory (afferent): carries signals from the PNS into the CNS Motor (efferent): carriers signals from the CNS to effectors (muscles/glands) in the PNS **Efferent = Exit CNS Interneuron: make decision based upon incoming signals from the afferent neurons & transmit response signal to the efferent neuron Describe three ways in which neuroglia are different from neurons: Size: neuroglia are much smaller in size than neuron Mitosis: neuroglia are able to replicate & fill in the gaps when non-mitotic neurons die Excitability: neuroglia are not excitable cells while neurons function depends solely on their excitability Describe the following neuroglial cells of the CNS & PNS: Neuroglia of the CNS: Astrocytes: maintain blood-brain barrier & provide nutrients to the neurons of the brain Oligodendrocytes: myelinate multiple axons of neurons in the CNS Microglia: fight off infection & clean up parts of dead cells to protect other neurons Ependymal Cells: modified epithelial cells that line fluid filled spaces (such as the ventricles) and generates CSF in the CNS Neuroglia of the PNS: Schwann Cells: myelinating cell of the PNS; can only myelinate ONE segment of ONE axon Satellite Cells: protect & take care of cell bodies in ganglia (nanny of PNS) Compare & contrast Schwann Cells vs Oligodendrocytes: Schwann Cells: Oligodendrocytes Myelinate axons in PNS Myelinate axons in CNS Myelinate ONE axon at a time Myelinate MULTIPLE axons at the same time Describe the purpose of myelin: increase the speed of signal conduction - Loss of myelin = slower speed of signal conduction Describe how Myelination + Axon Diameter influence the conduction speed of an action potential down an axon: Myelination & Axon Diameter Influence Conduction Speed: Diameter of Axon: larger = quick; smaller = slow Myelination of Axon: present = quick; absent = slow Small, unmyelinated axons = slowest Small, myelinated axon = medium speed Large, myelinated axon = quickest Name the disease characterized primarily by the loss of myelin: Multiple Sclerosis Define polarity: Polarity: separation of charge across a membrane (unequal distribution of charge) - Plasma membranes of neurons are POLAR since they have a RMP of -70mV Describe the role of the Na/K ATPase Pump in establishing the Resting Membrane Potential (RMP) within the membrane of the neuron: Na/K ATPase Pump: maintains polarity of the neuron cell membrane by sending 3 Na out of the cell & bringing in 2 K ions per pump cycle; one cycle of the pump results in -1 charge inside the cell - Cycling continues until RMP is achieved (-70mV) - ATPase Pump = type of PRIMARY ACTIVE TRANSPORT (because ATP used as energy to move the ions against their concentration gradients) Compare & contrast facilitated diffusion vs active transport: Facilitated Diffusion: - Requires ONLY a membrane protein through which the ion moves into or out of the cell - NO ENERGY used (ion DIFFUSES down its concentration gradient when the channel is open) - Ex: Ligand-Gated Na Channels, Voltage-Gated Na Channels, Voltage-Gated K Channels Active Transport: - Requires a membrane protein through which the ion moves into or out of the cell & Energy (ion moves up its concentration gradient when the channel is open) - Ex: Na+/K+ ATPase Pump Name the key difference between Ligand-Gated & Voltage-Gated Ion Channels: Ligand Gated Ion Channels: open in response to binding of a ligand (such as a neurotransmitter) Voltage-Gated Ion Channels: open in response to a change in voltage within the membrane Describe the term Graded Potential: Graded Potentials: local depolarization potential caused by opening of ligand-gated channels - Occur in the dendrites or soma of the neurons - Small deviations from the resting potential (such as -70 mV to -67 mV); not enough to trigger an action potential Summation of graded potentials that reach the action potential threshold value triggers the opening of Voltage-Gated Na+ Channels. Describe the term Depolarization: Depolarization: positive deviation in the voltage of the cell membrane; movement of + ion into the neuron - Excitatory Postsynaptic Potential (EPSP): a small depolarization event occurs in response to ligand binding, opening a ligand gated ion channel, resulting in influx of that ion into the cells - EPSP & graded potential are interchangeable words - EPSP: depolarization less than action potential threshold value of -55mV Describe the term Hyperpolarization: Hyperpolarization: negative deviation in the voltage of the cell membrane - Inhibitory Postsynaptic Potential (IPSP): a small hyperpolarization event in response to inhibitory ligand binding & opening ligand-gated Cl channel, Cl (-) influx into the neuron = more negative charge inside the cell - Hyperpolarization makes the neuron less likely to fire an action potential Compare & contrast Depolarization vs Hyperpolarization: Inhibition of Presynaptic Potential = Hyperpolarization = membrane potential LESS than RMP (valley) Excitation of Presynaptic Potential = Depolarization = membrane potential GREATER than RMP (hill) Compare & contrast temporal vs spatial summation: Temporal Summation: lots of stimuli occurring in close time - Typically one neuron sending several EPSPs over a short amount of time Spatial Summation: lots of stimuli occurring in close area - Typically several neurons sending EPSPs over a small area Name the structure of the neuron where graded potentials are summated & the action potential begins if threshold is reached: Axon Hillock Describe the three phases of an Action Potential (including the opening/closing of ion channels/movement of ions through the channels): Three Phases of the Action Potential: 1. Depolarization Phase: Na flows into the cell; inside of the cell more positive (mV closer to zero), opening voltage gated sodium channels - Opening of voltage gated Na channels causes LARGE rush of Na into the cell, depolarizing the cell 2. Repolarization Phase: movement of K+ out of the cell (removing positive from inside cell) retuning the inside of the cell closer to RMP (-70 mV) 3. Hyperpolarization Phase: K channels are slow to close; more K leaks out than what is needed to reach -70 mV (overshoot RMP of -70mV) Name the numeric values of the following membrane potentials: Resting Membrane Potential (RMP): -70 mV Action Potential Threshold: -55 mV Using the action potential graph below, understanding the temporal manner of ion channel opening & how the movement of ions creates the three phases of the action potential: a: RMP of -70 mV b: Action Potential Threshold of -55 mV c: Na+ moving into of the cell d: K+ moving out of the cell 1: Ligand-Gated Na+ Channels Opening in response to ligand (neurotransmitter) binding **Ligand Gated Channels Opening creates Graded Potentials **Summation of Graded Potentials = Action Potential Threshold (b) 2: Voltage-Gated Na+ Channels open (in response to Action Potential Threshold value within the membrane) - Voltage-Gated K+ Channels closed 3: Voltage-Gated Na+ Channels QUICKLY Inactivate - Voltage-Gated K+ Channels open 4: Voltage-Gated Na+ Channels inactive & closing - Voltage-Gated K+ Channels Open 5: Voltage-Gated Na+ Channels Closed - Voltage-Gated K+ channels closing/closed **Na+/K+ ATPase Pump restores RMP in the membrane 6: Na+/K+ ATPase maintains resting membrane potential at -70 mV **All voltage gated channels CLOSED Label the absolute & refractory periods on the following graph of an action potential: Describe the physiological purpose of a refractory period: Refractory periods ensure one-way transmission of the action potential. Compare & Contrast Absolute vs Relative Refractory periods of an action potential: Absolute Refractory Period: another Action Potential ABSOLUTELY cannot occur - Voltage-gated Na channels open or inactive & cannot be re-opened to trigger Action Potential - RED portion on the graph above Relative Refractory Period: a stronger than normal stimuli required to trigger an Action Potential - Hyperpolarization = membrane voltage less than RMP & must be overcome to trigger Action Potential - Relative Refractory Period ends once Na/K ATPase pump re-establishes RMP - YELLOW portion of the graph above Describe the two methods of nerve signal propagation: Continuous Propagation: movement of a nervous signal along an unmyelinated axon Saltatory Propagation: movement of a nervous signal along a myelinated axon Name the locations of each of the following synapses: Axodendritic: connection between axon & dendrite Axosomatic: connection between axon & cell body Axoaxonic: connection between axon & axon Compare & contrast chemical vs electrical synapses: Chemical Synapses: transmit the signal from presynaptic to postsynaptic neuron using ligands/neurotransmitters that are released into a synapse. Electrical Synapses: used by the cells in the heart to transmit contraction signal directly between adjacent cells Describe the steps of signal transmission within a chemical synapse: Seven Steps of the Chemical Synapse: 1. Action Potential comes down the presynaptic axon & arrives at the axon terminal 2. Voltage-Gated Calcium Channels open on the presynaptic membrane 3. Calcium floods into the axon terminal 4. Calcium stimulates exocytosis of vesicles containing neurotransmitters into the synaptic cleft 5. Neurotransmitters flow through the synapse 6. Neurotransmitter bind ligand-gated ion channels on the postsynaptic membrane 7. Na+ Channel opens = sodium flows down concentration gradient (+ moves into the cell) = depolarization, bringing membrane closer to Action Potential Threshold - Cl- Channel opens = Cl- flows down concentration gradient (- moves into the cell) = hyperpolarization **Na vs Cl channel opening depends on the type of neurotransmitter/ligand **If Action Potential Threshold is met, Voltage gated Na+ Channels open to transmit the signal down the postsynaptic neuron** Describe the following types of neurotransmitter receptors located in the nervous system: Ionotropic Receptors: ligand gated ion channels - Binding of neurotransmitter to these receptors causes opening of an ion channel, allowing movement of an ion into or out of the neuron Metabotropic Receptors: associated with a ligand gated ion channel (but not one itself) - Second messenger cascade of signaling in response to neurotransmitter binding to this receptor causes opening of an adjacent ion channel, allowing movement of an ion into or out of the neuron Describe the three methods of removing neurotransmitters from the synaptic cleft: 1. Diffusion: flow of neurotransmitter from high concentration (in the synapse) to low concentration (outside of the synapse) 2. Enzymatic Degradation: enzyme chews up neurotransmitter to take away function (ex: acetylcholinesterase digests acetylcholine to help remove it from the synapse) 3. Uptake by Astrocytes: vacuuming the neurotransmitter up by the pre or postsynaptic cell - EX: Reuptake inhibitors like SSRIs & SNRIs used for treatment of depression & anxiety Week 13: The Central Nervous System Define the following anatomical terms of the central nervous system: Rostral: directional term referring to the front of the brain (toward the forehead) Caudal: directional term referring to the back of the brain (toward the spinal cord) Gyri: part of the neocortex that projects as a bump superficially Sulci: part of the neocortex that grooves within the surface of the brain Nuclei: groups of cell bodies in the CNS - Groups of cell bodies in PNS = Ganglion Tracts: bundles of axons in the CNS - Bundles of axons in PNS = Nerves Describe the function of the following protective structures of the CNS: Skeletal Protection: - Skull = Brain - Vertebrae = Spinal Cord Meninges: 3 layers of connective tissues - From superficial to deep: Dura Mater, Arachnoid Mater & Pia Mater Cerebral Spinal Fluid (CSF): fluid located within four ventricles of the brain & surrounding the brain/spinal cord Functions: shock absorption, maintaining control of ions, exchange nutrients & waste, cushioning of the brain - CSF produced by the choroid plexus of the ependymal cells within the ventricles Label the following layers of protective structures of the Brain: A: Skeletal Protection- Bone of the Skull B: Pia Mater C: Arachnoid Mater D: Meningeal Dura E: Periosteal Dura Label the following layers of protective structures of the Spinal Cord: A: Skeletal Protection- Vertebrae B: Dura Mater​ C: Arachnoid Mater​ D: Pia Mater Describe the dural layers that make up each dural space & what fills each dural space: Epidural Space: between the bone & dura mater - Filled with: Fat tissue Subdural Space: between the dura & arachnoid mater - Filled with: NOTHING Subarachnoid Space: between the arachnoid & pia mater - Filled with: Cerebral Spinal Fluid Describe the pathway of CSF circulation within the nervous system: 1: Produced by choroid plexus in the ventricles 2: Circulates within the subarachnoid space around the entire brain & spinal cord 3: Diffuses out of the subarachnoid space and into the dural venous sinuses via arachnoid villi - Subarachnoid Space contains only CSF - Dural Venous Sinuses contains venous blood + CSF 4: Fluid returns to general circulation via drainage of venous blood from the brain via the jugular vein Describe the functions of the following vessels & their roles in the blood circulation of the CNS: Internal Carotid Artery & Vertebral Arteries: supplies oxygen rich blood to the brain Dural Venous Sinuses & Internal Jugular Vein: drains oxygen poor blood from the brain Anterior & Posterior Spinal Arteries: supplies oxygen rich blood to spinal cord Anterior & Posterior Spinal Veins: drains oxygen poor blood from the spinal cord Label the following vessels of the Circle of Willis supplying the brain: Describe the function of the Blood Brain Barrier & include a few examples of what this structure allows into the brain & what it excludes from the brain: Blood Brain Barrier: tightly connected endothelial cells + astrocytes that controls the nutrients allowed in & toxins blocked from entering Allowed into Brain: Glucose, Oxygen/Carbon Dioxide, Anesthesia Medications, Alcohol & other Drugs Not Allowed: toxins, antibiotics, most proteins, cells Describe the regions of the spinal cord including the number of vertebrae within & spinal nerves originating from each area? Cervical Spinal Region: C1-C8 spinal nerves (8 pairs of spinal nerves) - Spinal nerve C1 exits superior to cervical vertebra 1 and C2 exits inferiorly [7 vertebrae but 8 spinal nerves] Thoracic Spinal Region: T1-T12 spinal nerves (12 pairs of spinal nerves) Lumbar Spinal Region: L1-L5 spinal nerves (5 pairs of spinal nerves) Sacral Spinal Region: S1-S5 spinal nerves (5 pairs of spinal nerves) Coccyx Spinal Region: ONE spinal nerve (Co1) Describe the reasoning behind the target location of a spinal tap & what this diagnostic test is sampling: Lumbar Puncture: (aka Spinal Tap) - Medical test involving the collection of a small sample of CSF to test for infection or inflammation - Target for needle insertion for gathering CSF: within the Cauda Equina of the spinal cord located at or below vertebral levels L1/L2 Label the anatomy of the spinal cord below: Dorsal Root Ganglion: contains cell bodies of sensory fibers Dorsal Root: sensory fibers only Ventral Root: motor fibers only Name the structures of nerve that are present in the dorsal root ganglion: The Dorsal root ganglion is an enlargement that contains only sensory cell bodies. Describe the origin of the following nerves: Cranial Nerves: originate from the brainstem Spinal Nerves: originate from the spinal cord Describe the following structures surrounded by each of the following nerve tissue coverings: Endoneurium: surrounds single nerves (including myelin) Perineurium: surrounds fascicles of neurons - Blood vessels travel through the perineurium Epineurons: surrounds entire nerves Label the following diagram of the brainstem & cerebellum: Describe the function of the thalamus: Relay center for incoming sensory information that will direct the afferent signals to their respective primary somatosensory areas of the cerebral cortex. Describe the general functions of each area of the Brainstem & Cerebellum: Brainstem: located at the junction between the brain and spinal cord; functions as a relay center for motor and processing center (sensation) for vision, hearing & governs reflexes vital for live Reflexes Vital for Life: blood pressure, HR, breathing rate, blinking, hunger Cerebellum: functions in Motor coordination; Regulating BP, HR & other unconscious reflexes Three Principle Parts of the Brainstem: A: Midbrain: sensory relay center- takes information from the outside world and translates it so it can be better understood by the brain - Functions with thalamus to edit sensory information B: Pons: ball shaped; motor coordination center - Contains pneumotaxic & apneustic areas essential for breathing/control of the respiratory system C: Medulla Oblongata: medullary cardiac rhythmicity center; essential for heart rate/cardiac control Label the following sensory areas of the brain & understand each area’s basic function: A: Primary Olfactory Area: smell B: Primary Auditory Cortex: hearing C: Primary Gustatory Area: taste D: Primary Somatosensory Areas: general touch/sensation E: Primary Visual Cortex: vision Label the following motor areas of the brain & understand each area’s basic function: A: Primary Motor Cortex: general somatic motor B: Broca’s Area: speech production Label the following association areas of the brain & understand each area’s basic function: A: Auditory Association Area: association of sounds with memory B: Prefrontal Cortex: personality & executive function C: Premotor Cortex: muscle memory & motor planning D: Somatosensory Association Area: puts incoming sensations into context E: Wernicke’s Area: processing/understanding of speech F: Visual Association Area: tiger in a zoo vs tiger on campus Compare & contrast Broca’s vs Wernicke’s areas of the brain: Broca’s Area: speech production; loss of Broca’s area = produce speech due to loss of muscle function Wernicke’s areas: production of coherent speech; loss of Wernicke’s Area = cannot understand meaning of words (word salad) Weeks 14 & 15: The Peripheral Nervous System Label the following diagram of the spinal nerve origin from the spinal cord: Describe the term plexus: Plexus: branching network of nerves that supply a region of the body - EX: Brachial Plexus: network of 5 main nerves that supply the upper limb Describe the three principal plexuses of the PNS: Three Principle Plexuses in the PNS: ONE: The Cervical Plexus: sensory plexus from scalp, face & neck TWO: The Brachial Plexus: Sensory & motor information to/from the upper limbs (C5-T1 region) - Axillary Nerve = shoulder - Radial Nerve: Posterior arm & forearm - Musculocutaneous Nerve: anterior arm - Medial Nerve: Anterior forearm & hand - Ulnar Nerve: Hand THREE: The Lumbosacral Plexus: sensory & motor information to/from the lower limbs & pelvis (including pelvic organs) - L1-S5 Two Key Branches of the Lumbosacral Plexus: 1. Femoral Nerve: anterior aspect of the lower limb 2. Sciatic Nerve: posterior aspect of the lower limb - Sciatica: compression of intervertebral disc causing pain/tingling down the posterior aspect of the lower limb 3: Obturator Nerve: medial aspect of the thigh Define the following terms related to spinal cord injury: Paraplegia: loss of motion/sensation from both lower limbs Quadriplegia: loss of motion/sensation from both upper & both lower limbs Hemiplegia: loss of motion/sensation from the upper & lower limbs on one side of the body Paresis: weakness of a body part (not paralysis) Describe the three modality types used to classify cranial nerves: Sensory: contain only sensory axons & responsible for sensory functions (afferent fibers) Motor: contain only motor axons & responsible for motor functions (efferent fibers) Both: contain axons of both sensory & motor neurons (afferent & efferent fibers) Complete the following chart: Cranial Nerve: Modality: Function: I: Olfactory (Oh) Sensory (Some) Smell II: Optic (Oh) Sensory (Say) Vision via the Optic Nerve to the Occipital Lobe III: Oculomotor (Oh) Motor (Marry) Movement of the eye & Proprioception; adjust shape of lens & size of pupil ****Exception to eye muscle motor innervation: SO4LR6 IV: Trochlear (To) Motor (Money) Intorsion of the eye via innervation of the Superior Oblique muscle V: Trigeminal (Touch) Both (But) Sensory: both upper & lower lips, mouth, face & scalp Motor: muscles of mastication VI: Abducens (And) Motor (My) Abduction of the eye via innervation of the Lateral Rectus muscle VII: Facial (Feel) Both (Brother) Sensory: taste from the anterior ⅔ of the tongue Motor: muscles of facial expression VIII: Sensory (Says) Hearing & Balance Vestibulocochlear (Very) IX: Glossopharyngeal Both (Big) Sensory: taste, BP, pH detection via chemoreceptors & baroreceptors (Good) Motor: muscle of the pharynx & smooth muscle of the parotid gland X: Vagus (Veggies) Both (Brains) Sensory: parasympathetic fibers Motor: smooth muscle of lungs, heart & GI tract **ONLY CN whose innervation extends inferior to the head/neck 001 XI: Accessory (And) Motor (Matter) Innervation of Trapezius & Sternocleidomastoid XII: Hypoglossal Motor (More) Innervate muscles of the Tongue for speech, movement of food & (Hams) swallowing **Make sure you are able to identify Cranial Nerves by their Roman Numeral- this is how they will be tested on the exam* Label the key anatomical features of CN I on the diagram below: A: Olfactory Bulb B: Olfactory Tract C: Fila Olfactoria D: Olfactory Epithelium E: Cribriform Plate During a traumatic event, structure Cribrifom Plate can shear structure Fila Olfacrotia. Name each structure below and understand the consequence of this cranial nerve injury: Cribriform plate (E) can shear Axons of the olfactory sensory neurons (C- Fila Olfactoria) resulting in loss of sense of smell. Name the four muscles of the eye innervated by CN III. Name the exceptions this rule of innervation for muscles of the eye: Superior Rectus, Inferior Rectus, Medial Rectus, Inferior Oblique EXCEPTIONS: SO4LR6: Superior Oblique innervated by CN IV & Lateral Rectus innervated by CN VI Describe the following structural & functional classifications of reflex arcs: Structural: - Cranial Reflex: integrative center is the medulla oblongata of the brainstem - Spinal Reflex: integrative center is the lateral horn of the spinal cord Functional Classifications: - Somatic Reflex: influence the action of skeletal muscle - Autonomic Reflex: influence the action of smooth & cardiac muscle Describe the general steps shared by every reflex arc: General Steps for EVERY reflex arc: 1. Sensory receptor activation in response to a stimulus 2. Sensory neuron transmits impulse to CNS 3. Interneurons Process information [Integration Center] Integrating center: interneurons in CNS synapse to process incoming information - Monosynaptic reflex arc (rare): synapse between sensory & motor neuron - Polysynaptic Reflex Arc (more common): interneuron between sensory & motor neuron 4. Motor neuron transmits impulse to the effector 5. Effector responds to the signal *** Autonomic reflexes contain two motor neurons extending from the CNS to the effector while somatic reflexes typically only have one neuron from CNS Describe the location of the following structures within an autonomic reflex pathway: Preganglionic neuron = before ganglion synapse; carried information - Cell bodies of preganglionic neuron is located in the lateral horn of the spinal cord- only thoracic & lumbar segments Autonomic Ganglion: gathering of cell bodies within the PNS where the synapse occurs between preganglionic & postganglionic neuron Postganglionic neuron = after ganglion synapse; carries information to the effector - Cell bodies of postganglionic neuron in ganglion of the sympathetic chain Compare & contrast the pathways of somatic vs autonomic reflexes: Somatic Reflex: One myelinated neuron carrying signal to effector under voluntary control (skeletal muscle) Autonomic Reflex: Two neurons - only preganglionic neuron has myelin - Postganglionic neuron carries signal to effectors controlled involuntarily (heart) Describe the Sympathetic Chain: A string of ganglion in which preganglionic & postganglionic neurons synapse or pass through prior to going to their effector destination. Describe the three pathways in which an autonomic innervation can travel to its destination: Common pathway of all three routes: exits lateral horn of the spinal cord, travel through the true spinal nerve & white ramus communicantes, into the sympathetic chain 1: Synapse & exit occurs at the same level within the sympathetic chain via grey ramus communicantes 2: Preganglionic neuron goes up or down a level within the sympathetic chain prior to synapsing & exiting via grey ramus communicantes 3: Preganglionic neuron uses Splanchnic nerve to leave the sympathetic chain; enters the prevertebral ganglion where synapse occurs Compare & contrast sympathetic vs parasympathetic responses of the autonomic nervous system: **All autonomic signaling pathways (parasympathetic & sympathetic) contain 2 motor neurons - IN CONTRAST TO Somatic signaling that use only 1 motor neuron Parasympathetic Nervous System: Sympathetic Nervous System: Rest & Digest Fight or Flight or Freeze (Rapid ATP production) Controlled by craniosacral distribution Controlled by thoracolumbar distribution Long Preganglionic & Short Postganglionic neurons Short preganglionic & Long postganglionic neurons Heart Rate & Blood Pressure DECREASE Heart Rate & Blood Pressure INCREASES Digestion INCREASES Digestion DECREASES Increased urine production Decreased urine production Categorize the senses as either general or special; describe what is meant by a special sense: Special Sense: conversion of a stimulus modality (sound waves, light waves, etc) into electrical stimuli that is understood by the CNS - Examples of special senses: olfaction, gustation, audition, vision General Sense: Touch Name the type of membrane channel that is initially opened by touch: Mechanically gated ion channels Describe the term Receptive Field: The number of neurons within a receptive area correlates to the ability to distinguish between two points of touch - High density of neurons = sense two stimuli as separate = Hand - Low density of neurons = sense two stimuli as the same = Back Define Dermatome & Referred Pain: Dermatome: skin segments supplied with somatic sensation by one spinal nerve Referred Pain: pain originating from an organ is perceived as cutaneous pain (closer to the skin surface) Describe what triggers depolarization/action potentials in Olfaction: Odorant chemicals bind to specialized olfactory cells called fila olfactoria. - Olfactory epithelium provides the ability to smell; Olfactory epithelium contains the fila olfactoria sensory neurons Name the type of lingual papillae that lack taste buds: Filiform Papillae = NO TASTE BUDS Contain taste buds: Circumvallate papillae, foliate papillae, fungiform papillae Label the following basic elements of ear anatomy: A: Pinna B: External Auditory Canal ​ C: Tympanic Membrane ​ D: Malleus ​ E: Incus ​ F: Stapes ​ G: Cochlea​ H: Semicircular Canals​ I: Vestibulocochlear Nerve (CN VIII) ​ J: Eustachian Tube Describe why children and babies are more prone to ear infections: Angle of the eustachian tube Describe the basic mechanism in which the cochlea detects sounds of different frequencies: 1: Sound waves hit the tympanic membrane which causes movement of the associated auditory ossicle bones, causing the oval window of the cochlea to vibrate with the same frequency 2: Vibration of the oval window produces pressure waves in the perilymph which vibrates the basilar membrane 3: Pressure waves from high frequency sounds travel SHORT distances into the cochlea, causing the basilar membrane to vibrate where it is narrow & stiff 4: Pressure waves from low frequency sounds travel FURTHER into the cochlea & cause the basilar membrane to vibrate where it is wide & flexible Describe the following structures of the Vestibular Sense: Semicircular Ducts: detect angular movement Endolymph: fluid of the inner ear Otolith Organs: detect linear movement Name the three cranial nerves that innervate muscles of eye movement: CN III, CN IV, CN VI Label the following diagram of the eye: A: Cornea B: Iris ​ C: Pupil ​ D: ----------------​ E: Lens ​ F: Optic Nerve (CN II) Describe the the role of Rods & Cones in Vision: Rods: produce low acuity vision, cannot detect color & unable to function in bright light - Sensitive in dim light (black-white-grey image) Cones: contain pigment allowing for the perception of color; produce high acuity vision Describe the differences between near-sighted & far-sighted visual impairments: Near-Sighted Vision: objects at a far distance are blurry Far-Sighted Vision: objects close up are blurry