HAP II Final Exam (Vocab and Labeling)

Olfactory Nerve (CN I)

sensory - olfaction / smell

innervates the nose (nasal mucosa)

Optic Nerve (CN II)

sensory - vision

innervates the eye

Oculomotor Nerve (CN III)

(motor)

somatic motor: momst eye movement

parasympathetic: pupillary dilation, accommodation

innervates the eye muscles

Trochlear Nerve (CN IV)

(motor)

somatic motor: contracts superior oblique muscle

innervates the superior oblique of eye

Trigeminal Nerve (CN V)

(mixed)

somatic sensory: skin of face, tongue, mucosa of mouth

somatic motor: mastication muscles (chewing)

innervates skin of face and tongue muscles

Abducens Nerve (CN VI)

(motor)

somatic motor: lateral movement of eye

innervates lateral rectus of eye

Facial Nerve (CN VII)

(mixed)

somatic sensory: outer ear; anterior 2/3 of tongue

somatic motor: facial expressions

parasympathetic: most gland secretions in the head

innervates the tongue, most skeletal muscle of the face, and lacrimal and salivary glands

Vestibulocochlear Nerve (CN VIII)

sensory - hearing and equilibrium

innervates the inner ear (cochlea and vestibular apparatus)

Glossopharyngeal Nerve (CN IX)

(mixed)

somatic sensory: taste to posterior 1/3 of tongue; epiglottis

somatic motor: swallowing and breathing

parasympathetic: parotid gland secretion

innervates tongue, muscles in the pharynx, and parotid gland

Vagus Nerve (CN X)

(mixed)

somatic sensory: external ear cartilage

somatic motor: swallowing using muscles of pharynx and larynx

parasympathetic: all PS innervation of visceral organs from neck to transverse colon

innervates the external ear, muscles in pharynx and larynx, and all visceral organs from the neck to the transverse colon

Accessory Nerve (CN XI)

(motor)

somatic motor: turns head and shrugs shoulders

innervates sternocleidomastoid and trapezius

Hypoglossal Nerve (CN XII)

(motor)

somatic motor: tongue protrusion and retraction

innervates the tongue

What is 1 pointing to?

olfactory nerve (CN I)

What is 2 pointing to?

oculomotor nerve (CN III)

What is 3 pointing to?

trochlear nerve (CN IV)

What is 4 pointing to?

abducens nerve (CN VI)

What is 5 pointing to?

vestibulocochlear nerve (CN VIII)

What is 6 pointing to?

hypoglossal nerve (CN XII)

What is 7 pointing to?

accessory nerve (CN XI)

What is 8 pointing to?

optic nerve (CN II)

What is 9 pointing to?

trigeminal nerve (CN V)

What is 10 pointing to?

facial nerve (CN VII)

What is 11 pointing to?

glossopharyngeal nerve (CN IX)

What is 12 pointing to?

vagus nerve (CN X)

What is 1 pointing to?

cervical plexus

What is 2 pointing to?

brachial plexus

What is 3 pointing to?

lumbar plexus

What is 4 pointing to?

sacral plexus

Dorsal portion of spinal cord

posterior; receives sensory info from body

Ventral portion of spinal cord

anterior; sends motor command from brain to body

Dorsal horn

gray matter in posterior spinal cord; synapse site for incoming sensory neurons; interneurons; within the CNS direction of info. flow)

Ventral horn

gray matter in anterior spinal cord; contains motor neuron cell bodies; motor neurons; within CNS (direction of info. flow)

Dorsal root

posterior side of spinal cord; carries sensory input into the spinal cord; sensory neurons (afferent); toward CNS (direction of info. flow)

Ventral root

anterior side of spinal cord; carries motor output away from the spinal cord; motor neurons (efferent); away from CNS (direction of info. flow)

Dorsal root ganglion

on dorsal root (outside spinal cord); contains cell bodies of sensory neurons; sensory neuron cell bodies; sends signals to dorsal horn

Sensory input pathway and motor output pathway

sensory input pathway: sensory neurons — dorsal root ganglion — dorsal root — dorsal horn (synapse)

motor output pathway: ventral horn (motor neuron cell bodies) — ventral root — muscles

Exteroceptors

found near body surfaces (skin, eyes, ears, etc.); detects external stimuli from outside the body;

ex: touch, temperature, pain (from skin), vision, hearing, smell (most of special senses)

Interoceptors

found inside the body (viscera, blood vessels); detects internal stimuli from organs and tissues; often not perceived

ex: blood pressure, pH, oxygen levels, stretch in GI tract (chemical changes, temperature, pain, thirst, hunger, etc);

Proprioceptors

found in skeletal muscles, tendons, joints, ligaments, and connective tissues around bones and muscles; detects body position and mvoement awareness (via stretch receptors)

Nonencapsulated

nonmyelinated and have small bulbous ends; mostly in epithelia and connective tissue; free nerve endings (bare dendrites); light touch, pain, temperature, itch

Encapsulated

nerve endings wrapped in connective tissue capsule; mostly in dermis, joints, muscles; precise touch, pressure, stretch, vibration, proprioception

Mechanoreceptors

mechanical forces (pressure, touch, vibration, stretch); located in skin, muscles, ears, vessels, organs

Thermoreceptors

temperature changes; located in skin and hypothalamus

Photoreceptors

light changes; located in retina of the eye

Chemoreceptors

chemical changes (smell, taste, blood interstitial fluid); found in nose, tongue, blood vessels

Nociceptors

pain (extreme cold, heat, intense pressure, inflammation); located almost everyehere (especially skin & organs); often stimulate subtypes of the other receptors

Free nerve endings of sensory neurons (receptors)

structural class / where: nonencapsulated (most body tissues)

functional location: exteroceptors, interoceptors, proprioceptors

functional stimulus: thermoceptors, chemoreceptors, mechanoreceptors, nociceptors

Modified free nerve endings (Merkel cells and discs) receptors

structural class / where: nonencapsulated (basal epidermal layer)

functional location: exteroceptors

functional stimulus: mechanoreceptors (light pressure)

Hair follicle receptors

structural class / where: nonencapsulated (surrounding hair follicle)

functional location: exteroceptors

functional stimulus: mechanoreceptors (hair deflection)

Tactile corpuscles (Meissner’s) receptors

structural class / where: encapsulated (dermal papillae in hairless skin)

functional location: exteroceptors

functional stimulus: mechanoreceptors (light pressure, discriminative / precise touch, low frequency vibration)

Lamellar corpuscles (Pacinian) receptors

structural class / where: encapsulated (dermis, hypodermis, tendons, ligaments, joints)

functional location: exteroceptors, interoceptors, some proprioceptors

functional stimulus: mechanoreceptors (deep pressure, stretch, high frequency vibration)

Bulbous corpuscles (Ruffini endings) receptors

structural class / where: encapsulated (deep in dermis, hypodermis, joints)

functional location: exteroceptors, proprioceptors

functional stimulus: mechanoreceptors (deep pressure, stretch)

Muscle spindles receptors

structural class / where: encapsulated (around muscle fascicles)

functional location: proprioceptors

functional stimulus: mechanoreceptors (muscle stretch, length)

Tendon organs receptors

structural class / where: encapsulated (around tendons)

functional class: proprioceptors

functional stimulus: mechanoreceptors (tendon, stretch, tension)

Joint kinesthetic receptors

structural class / where: encapsulated (capsule of synovial joint)

functional location: proprioceptors

functional stimulus: mechanoreceptors, nociceptors

Somatic reflec arcs

receptors, sensory neuron, integration center (interneuron), motor neuron, effector

not perceive because doesn’t go to cortex; stays in spinal cord

Receptor level

detection at sensory receptors

Circuit level

processing in ascending pathways (spinal cord)

Perceptual level

processing in sensory area of the brain

Somatosensory cortex

receives and processes sensory input from the body; located in postcentral gyrus of parietal lobe

Motor cortex (primary motor cortex)

sends motor output to skeletal muscles; located in precentral gyrus of the frontal lobe; sends signals via upper motor neurons — spinal cord — lower motor neurons — efectors (muscles)

Phasic receptors

detect changes in the environment; respond quickly at first then stop firing if stimulus remain; fast adapting

ex: Meissner’s corpuscles, Pacinian corpuscles, olfactory receptors

Tonic receptors

detect continuous stimuli; continue firing as long as stimulus is present; slow adapting

ex: nociceptors, proprioceptors, muscle spindles

Perceptual detection (sensory perception)

ability to detect that a stimulus occured (usually need several inputs summed)

Magnitude estimation (sensory perception)

ability to determine the intensity or strength of a stimulus

Spatial discrimination (sensory perception)

ability to localize the stimulus on the body

Feature abstraction (sensory perception)

ability to identify complex aspects of a stimulus

Quality discrimination (sensory perception)

ability to differentiate submodalities of a sense (different categories?)

Pattern recognition (sensory perception)

ability to recognize familiar patterns or combinations of stimuli

Graded (receptor) potential

temporary change in membrane voltage that happens when a stimulus (touch, taste, light) activates a sensory receptor; located on receptor membranes or dendrites; signal is local (fades with distance); summation (can add up if multiple stimuli happen close together); can lead to action potential if strong enough

Receptor potential

specific type of graded potential that occurs in sensory receptor cells (photoreceptors, olfactory neurons, mechanoreceptors); generated when a sensory stimulus causes ion channels to open or close; changes membrane potential based on stimulus strength; may trigger NT release (photoreceptors) or trigger action potentials

Transducin

G-protein found in photoreceptor cells in the retina; involved in visual signal transduction pathway

What is the order of light as it passes through the eye?

light — cornea — pupil — lens — vitreous humor — retina

Parasympathetic control over the pupil

sphincter pupillae muscle contracts: pupil contricts (size decreases)

Sympathetic control over the pupil

dilator pupillae muscle contracts: pupil dilates (size increases)

Photons

tiny packets/particles of light energy; enter the eye — hit retina — trigger visual process

Photoreceptors

specialized cells in retinae that detect light (rods and cones)

Rods

sensitive to low/dim light (night vision); don’t detect color; detect peripheral vision; low resolution

Cones

detect bright light and color; high resolution; concentrated in the fovea (detailed vision)

Phototransduction and ion flow in light

photons activate transducer; transducin activates PDE which breaks down cGMP into GMP; reduced cGMP causes cGMP-gated Na+ and Ca2+ channels to close; Na+ and Ca2+ ions stop flowing into the cell but K+ ions continue to exit; photoreceptor hyperpolarizes (membrane potential become more -); hyperpolarization reduced glutamate release at the synpase with bipolar cells; change in glutamate release alters bipolar cells activity which starts the visual signal cascase to the brain

Phototransduction and ion flow in dark

photoreceptors are depolarized (more + inside); cyclic GMP (cGMP) levels are high keeping cGMP-gated Na+ and Ca2+ channels open on the photoreceptor’s outer membrane; Na+ and Cl- ions flow into cell and creat inward current call dark current; keep photoreceptor slightly depolarized allowing it to continuously release NT glutamate to bipolar cells

Phosphodiesterase (PDE)

enzyme activated during phototransduction in photoreceptors; when light actviated rhodopsin it triggers transduction which activates PDE; breaks down cGMP into GMP; causes cGMP-gated ion channels to close (photoreceptor hyperpolarization)

Bipolar cell

type of neuron in retina that connects photoreceptors to ganglion cells; recevie NT signals (like glutamate) from photoreceptors; ON bipolar cells activated when glutamate decreases (light condition); OFF bipolar cells activated when glutamate increases (dark condition); transmit signals to ganglion cells

When does glutamate decrease / increase?

decreases in light

increases in dark

Ganglion cell

final output neuron of retina; receives input from bipolar cells; axons form optic nerve which carreis visual info to the brain; generate action potential that travel along optic nerve

Cyclic GMP (cGMP)

secondary messenger molecule inside photoreceptor cells; in the dark cGMP levels are high which keeps ion channels open (photoreceptor depolarizes); when PDE breaks down cGMP in light the ion channels close (photoreceptor hyperpolarizes)

Photoreceptor depolarizes

dark; cGMP levels are high; cGMP-gated Na+ and Ca2+ channels stay open; (+) ions flow into cell causing it to stay depolarized; cell continuously releases glutamate at teh synapse with bipolar cells

Photoreceptor hyperpolarizes

light hits photopigement (rhodopsin) activating transducin which activates PDE which breaks down cGMP; cGMP-gated Na+ and Ca2+ channels close; K+ keeps flowing out of cell making the inside of the cell more negative (hyperpolarized)

Glutamate

primary NT released by photoreceptors; released continuously in the dark due to depolarization; light-induced hyperpolarization reduces glutamate release

Rhodopsin

light sensitive photopigment found in rods (dim lighting); made of opsin (protein) and 11-cis-retinal; triggered by photon (retinal changes shape); activated tranducin — PDE — decrease cGMP — signal

11-cis-retinal

inactive (before light hits); bound to opsin in rhodopsin; keeps rhodopsin ready to detect light; when combined with opsin it forms rhodopsin

all-trans-retinal

active (after light hits); released after activation; triggers activation of rhodopsin; breaks away from rhodopsin after light is absorbed; release begins singal transduction (G-protein pathway)

Retinal

light sensor (derived from vitamin A); 11-cis-retinal (fits into opsin to form active photopigment) and all-trans-retinal (created after light hits it)

Opsin

protein (in photoreceptor cell); holds retinal in place and triggers signal cascase when retinal changes shape; doesn’t absorb light directly but amplified effect of retinal’s shape change

rodes: opsin and 11-cis-retinal = rhodopsin

cones: different opsin and retinal = photopsins (red, green, blue light)

Ciliary muscles

behind the iris; change the shape of the lens to focus on objects at different distances (accommodation)

objects near: muscles contract and lens becomes thicker and rounder

objects far: muscles relax and lens becomes thinner and flatter

Flattened lens vs bulging lens

flattened lens: focusing on distant objects

bulging lens: (rounded) focusing on closer objects

Emmetropic eye

normal vision; focal point is on retina

Myopic eye

nearsighted; focal point is in front of the retina (eyeball is too long)

How are myopic eyes corrected?

concave lens moves focal point further back (to normal position)

Hyperopic eye

farsighted; focal point is behind retina (eyeball is too short)