Neurobiology test 3

3 parts of ear

outer, middle, inner

From _____ _____ outward is considered the outer ear

Tympanic membrane

Sound progression

1. sound waves arrive at tympanic membrane

2. movement of the tympanic membrane causes displacement of the ossicles

3. movement of the stapes at the oval window establishes pressure waves in the perilymph of the scala vestibuli

______ wiggle when vibration occurs and moves towards the inner ear

ossicles (malleus, incus, stapes)

What does the tympanic membrane do?

transmits and amplifies sound

How much amplification occurs between the tympanic membrane and the oval window?

8-9x

What does the stapes do?

Moves like a piston to disrupt fluid in the cochlea

Round window is aka the ____ _____

release valve

along the way, the waves are acting with the _______ of ______-

organ of corti

external acoustic meatus

Canal leading to eardrum and middle ear

internal acoustic meatus

A passage for CN VIII from the inner ear to the brain.

What are the cochlea and vestibular apparatus embedded in?

bone

vestibular apparatus=

semicircular canal

-at 90 degrees to each other

-coordinates balance

stimulus of hearing

compression waves of air particles

frequency

pitch

amplitude

volume

in/out of inner ear

in-sound

out-action potential

branch of facial nerve runs thru

middle ear

tensor tympani

the muscle attached to the malleus; tensing the tensor tympani decreases vibration

- reduce transmission of loud noise

stapedius

the muscle attached to the stapes; tensing the stapedius decreases vibration

-reduce transmission of loud noise

The inside of the vestibule and cochlea are filled with

endolymph or perilymph

Vestibule

balance and equilibrium

maculae

sensory receptors for static equilibrium in the vestibule

-collection of hair cells detecting the center of gravity

-inside utricle or saccule

ampullae

a bulbous structure at the base of semicircular canals in the inner ear's vestibular system

-It houses sensory hair cells within a gelatinous structure called the cupula

-playing a crucial role in maintaining balance

cupulla

a gelatinous mass found in the ampulla of the semicircular canals; moves in response to the flow of the fluid in the canals

-motion sensor for rotational acceleration

saccule and utricle

2 chambers with endolymph in vestibule

-utricle connected to (u-shaped) semicircular canals

Cranial nerve 8

vestibulocochlear nerve

otoconia otoliths

-crystals in the macullae, can cause stereo

(Ear) synapsing occurs between _____ ____ and _____ ____

hair cells and afferent neurons

Where does sound land?

Superior aspect of the temporal lobe

Medial geniculate nucleus

Sound processing in the thalamus

lateral lemniscus

band of fibers carrying auditory information through the medulla and pons

corpora quadrigemina

located in the midbrain; contains reflex centers for vision and auditory reflexes

Auditory reflexes go through this

inferior colliculus

______ _____ is in the top of the nasal cavity

olfactory epithelium

-these run thru the cribriform plate

Inside nasal epithelium:

-olfactory receptors

- detect chemicals

-odorant molecule binds to receptor and activated G- protein and depolarizing event begins

How many genes are in the olfactory receptor class?

4-500

Visible structures on tongue

papilla

cranial nerves for taste

Facial (VII)

Glossopharyngeal (IX)

Vagus (X)

cranial nerves for smell

olfactory

vestibule of ear

head motion, gravity, and position, sending signals to the brain to maintain stability

dynamic equillibrium

maintains balance during rotational movement, using the semicircular canals

static equilibrium

maintains balance relative to gravity when still, using the utricle and saccule within the vestibule

semicircular canals

motion sensors, detecting rotational acceleration of the head in three-dimensional space

Everything has a layer of ___ mediating the taste

saliva

Taste pores have an opening where ______ make ______ available

-microvilli

-g-protein coupled receptors

All gustatory neurons have ______ cells

• they are subject to damage so they need to be replaced readily

• basal

2 classes of taste receptors

-g- protein couples

-direct ion channels

mediating sour and salty

Taste

CN 7 and 9 (tiny bit 10)

Functions of spinal cord

transmit, transmit, and integrate

transmitting info

-lots of pathways in the white matter

-most names start with where it's coming from and end with where they're going to (ascending or descending)

Ascending pathways

-dorsal white column

-dorsal spinocerebellar tract

-ventral spinocerebellar tract

-lateral spinothalamic tract

-ventral spinothalamic tract

Descending pathways

-ventral white commissure

-lateral reticulospinal tract

-lateral corticospinal tract

-rubrospinal tract

-medial reticulospinal tract

-ventral corticospinal tract

-vestibulospinal tract

-tectospinal tract

Cortical spinal tracts are most important

motor control

spinal thalamic

important sensory

rubrospinal

unique set of motor neurons

integration

-reflexes

-descending tracts have to come out at a spinal cord level

white matter

super highway

grey matter

off ramp to sideroads

somatic reflex

contraction of skeletal muscles

-receptor detection, signal transmission by a sensory neuron, central integration, signaling via a motor neuron, and effector muscle response

spinal cord is protected by

bone, meninges, CSF

meninges

pia mater

arachnoid mater

dura mater

Between the pia and white we have

CSF

A bulge is only on the _____ not the ______

dorsal root, ventral root

CSF is produced in

-choroid plexus (in each of the ventricles)

-support, protect, buffer

CSF functions

support, protect, buffer

Foramen magnum to L1 =

solid structure... spinal cord anatomy

-31 spinal nerve pairs

-31 spinal segments

-cervical= c1-c8

-thoracic nerves= t1-t12

-lumbar nerves= l1-l5

-sacral nerves=s1-s5

-coccygeal nerve=Co1

dermatomes

Skin areas innervated by specific spinal nerves

white matter structures of spinal cord

dorsal columns, lateral columns, ventral columns

grey matter structures of the spinal cord

posterior/dorsal horn, intermediate zone, anterior/ventral horn, and grey commissure with the central canal

Ventricles of brain

2 lateral ventricles, 3rd ventricle, 4th ventricle

-CSF flows thru these

Spinal enlargements

cervical and lumbar

___ ___ does not have an associated vertebrae bone

c8

_____ is fused in adulthood

Sacrum

Dermatomes

portion of skin innervated by which specific spinal nerve

4 main plexuses of ventral rami

cervical, brachial, lumbar, sacral

gray matter spinal cord organization

Ventral rami -> form _______----> nerve plexuses -----> 4 plexuses

interlaced bundles of nerve fibers

What happens when spinal nerves leave the CNS and PNS

branch into ventral/dorsal rami to innervate the body, while lower nerves form the cauda equina to exit lower down, changing from CNS-based, heavily myelinated tracts into peripheral nerves.

somatotopic

spatially mapped in the somatosensory cortex in correspondence to spatial events on the skin

anterolateral system

a somatosensory system that carries most of the pain information from the body to the brain

Cervical nerves

C1-C4/5 ish

-neck, thoracic cavity, diaphragmatic muscles

-phrenic= major nerve (c3-5)

cervical nerves overall function

motor control and sensation in the neck, shoulders, arms, and hands, while also controlling breathing and head movement

brachial

-C5 to T1

-gives way to axillary, muscular cutaneous, radial, ulnar

-roof and floor: deep investing fascia and prevertebral fascia

Thoracic nerves

T1-T12

-chest and abdominal muscles

ulnar nerve

C8-T1

-ring and pinky finger

-carries sensory info from the palm and the medial hand/ finger and sends motor commands to the wrist flexors/ intrinsic hand muscles

ulnar nerve function

controls fine motor movements of the hand (intrinsic muscles) and sensation in the pinky and half of the ring finger. It facilitates grip strength, finger adduction/abduction, and wrist flexion

musculocutaneous nerve

C5-C7

-anterior upper arm

-carries sensory info from shoulder region and motor commands to the deltoid muscle

musculocutaneous nerve function

flexion of arm at elbow, supination of forearm

median nerve

C5-C8, T1

-hand from ring finger to thumb

median nerve function

flexors of wrist and digits

radial nerve

C5-T1

-forearm - doesn't service hand

-carries sensory info from the posterior arm and motor commands to the triceps brachii, wrist extensors, and brachioradialis

radial nerve function

drives elbow extension (triceps), wrist extension, finger extension, and thumb extension/abduction

axillary nerve

C5-C6

-deltoid and teres minor

-carries sensory info from the shoulder region and motor commands to the deltoid muscle

axillary nerve function

lifting the arm (deltoid), rotator cuff ( teres)

Lumbar nerves

L1-L5

-femoral nerve- (Pectineus, Illiacus, rectus femoris, vastus intermedius, vastus lateralis, vastus medialis) QUADS

-obturator nerve: any ADDUCTOR

-tibial nerve(every muscle below knee)

-common fibular nerve (every muscle below knee)

femoral nerve sensory/motor

-carries sensory info from much of the thigh, leg, and foot and sends motor commands to the quads

femoral nerve function

primary nerve for walking, running, and climbing stairs by operating the QUAD muscles

Obturator nerve

-L3-L5

-adductor brevis

-adductor longus

-adductor magnus

-gracilis

obturator nerve sensory/motor

-carries sensory info from much of the thigh

-sends motor command to adductor muscle