Final Pt. 3

Question 1

What three features make the entrance into the ear?

Answer 1

auricle (pinna), external auditory canal (aucoustic meatus), typanic membrane (eardrum)

Question 2

What are the three ossicles/ their location?

Answer 2

maleus, incus, stapes, found in tympanic cavity

Question 3

Purpose of the ossicles?

Answer 3

transmit vibratory motion of eardrum to oval window, dampened by tensor tympani and stapedius muscle

Question 4

what does oval window and round window do?

Answer 4

OW- initiates movement of fluid to cochlea
RW- dissapates sound

Question 5

What make up the inner ear (2 parts)

Answer 5

membranous and bony labryinth

Question 6

What is the bony labyrinth?

Answer 6

contains vestibules, semicircular canals (involves in balance) , and cochlea
filled w/ perilymph

Question 7

What system is in bony labyrinth

Answer 7

static vestibular system- saccule and urtricle in vestibles maintain orientation of head w/ rest of body

Question 8

What is a vestible?

Answer 8

2 sacs of perilymph, house equilbirum maculae

Question 9

What is the membranous labryinth?

Answer 9

membranous sacs within bony labriyth, filled with endolymph

Question 10

Anatomy of semicircular canals?

Answer 10

membranous semicircular ducts line canals, each end has ampulla- house crista ampullaris, equilibrium receptors, respond to movements of head

Question 11

What is the cochlea?

Answer 11

a spiral bony chamber that extends from anterior vestibule, coils around modiolus
contains cochlear duct and organ of corti

Question 12

3 parts of cochlea?

Answer 12

scala vestibuli
scala media (cochlear duct- endolymph)
scala tympani (ends at round window)

Question 13

parts of scala media (3)?

Answer 13

bony spiral lamina
basilar membrane
Nerve VIII runs from organ of corti to brain

Question 14

High vs low pitch?

Answer 14

high- sounds cause deflection of basilar membrane to oval window
low- deflect away from oval window

Question 15

long fibers have a…

Answer 15

lower pitch

Question 16

how do sound vibrations cause impulses?

Answer 16

beat typamic membrane- pushes ossicles- presses fluid against windows- shearing force on hair cells- stim. coch nerve to send impulses

Question 17

inaudible vs audible sounds?

Answer 17

low vs high frequency
travel around heliocotrema vs. cochlear ducts
dont excite hair cells vs. excite basilar membrane

Question 18

Anatomy of organ of corti

Answer 18

inner/ outer hair cells
afferent fibers of cochlear nerve attach to basal hair cells

Question 19

what are sterocilia?

Answer 19

hair cells in organ of corti, protrude into endolymph, touch tectorial mebrane

Question 20

The excitation of hair cells in OOC does what?

Answer 20

opens mechanical ion channels, causes graded potential

Question 21

Inner vs outer hair cells?

Answer 21

inner hair cells: sensory, nerve endings that send acoustic info
outer hair cells : amplify basilar membrane (improve hearing sensitivity)

Question 22

Structures of hair cells?

Answer 22

attach to nerve VIII, have sterocillia, single kinocilim, linked by tiplinks

Question 23

DRAW hair cell

Answer 23

DRAW

Question 24

movement of the basilar membrane?

Answer 24

bending of hair cells put tension of tip links, opens K channels, causes graded depolarization- release of NT
Hair must bend towards tallest sternocillia for NT to be released

Question 25

Anatomy of crista ampullara?

Answer 25

receptor for dynamic equilibrium (balance, movement, eye impartiality)
each crista has hair cells extending into gel called the cupula

Question 26

How does crista respond to changes in velocity?

Answer 26

respond, result is brain informed of rotantional head movements

Question 27

Anatomy of maculae?

Answer 27

sensory receptors for static cells, sterocillia/kinocilla in otholithic membrane

Question 28

What is otholithic membrane?

Answer 28

jellylike mass with CaCO3 stones
horizontal movement- urtricular hairs
vertical movement- sacular hairs

Question 29

What is vestibular apparatus?

Answer 29

equilbrium receptors in semicircular canals and vetsible
static and dynamic equilibrium

Question 30

movement of head with kinocillia?

Answer 30

forward- towards kinocilloia (depolarize)
backwards- away kinocillia (hyperpolarize)

Question 31

Auditory pathway to brain?

Answer 31

cochlea-spiral ganglion- cochlear nuclei- superior olivary nucelus, inferior collicus

Question 32

Auditory pathway from auditory cortex?

Answer 32

dessucates, inferior collicus (auditory reflex center), thalamus, primary auditory cortex