L18: The Ear

Question 1

auricle

Answer 1

outer part of the ear

Question 2

describe the auricle

Answer 2

skin over elastic tissue
keratinized
stratified squame

consists of the pinna and auditory canal

Question 3

auditory meatus

Answer 3

the auditory canal

outer third of ear - elastic cartilage

inner 2/3s = bone

Question 4

lining of the auditory meatus

Answer 4

stratified squame
sebaceous glands
ceruminous glands

Question 5

ceruminous glands

Answer 5

modified sebaceous glands

for secreting ear wax

Question 6

tympanic membrane

Answer 6

the eardrum

separates the external auditory meatus from the middle ear

Question 7

compare the core - internal - external surfaces of the tympanic membrane

Answer 7

core - vascularized, innervated CT

internal - simple cuboidal

external - thin skin

Question 8

name the 3 auditory ossicles

Answer 8

ossicles = ear bones

1. malleus
2. incus
3. stapes - most interior

Question 9

ossicles that attaches the incus to the tympanic membrane

Answer 9

malleus

Question 10

intermediate ossicles between the malleus and stapes

Answer 10

incus

Question 11

ossicles that inserts on the oval window

Answer 11

stapes

Question 12

which ossicles provides an opening for the stapedial artery

Answer 12

stapes

Question 13

what are the metaphors for the ossicles?

Answer 13

malleus = hammer - strikes the anvil

incus = anvil

stapes = stirrups - like shape

Question 14

what are the openings from the middle ear to the cochlea

Answer 14

oval window

round window

Question 15

oval window

Answer 15

stapes attaches to the membrane covering the window

opens into the scala vestibuli

Question 16

round window

Answer 16

membrane covered region

at the end of scala tympani

Question 17

name the 2 muscles of the middle ear and where they insert

Answer 17

tensor tympani – on malleus

stapedius – on stapes

Question 18

what is the function of the middle ear muscles

Answer 18

thought to contract in response to loud noises in order to protect the ear

but recent discoveries prove not

Question 19

what are the 4 regions of the inner ear

Answer 19

1. bony labyrinth
2. membranous labyrinth
3. vestibular organ
4. auditory organ

Question 20

what is the bony labyrinth

Answer 20

a system of canals and chambers embedded in petrous portion of temporal bone

containing perilymph

Question 21

perilymph has a high ____ content

Answer 21

sodium

Question 22

what are the contents of the bony labyrinth

Answer 22

semicircular canals
cochlea
scala vestibuli
scala tympani

Question 23

what is the membranous labyrinth

Answer 23

a system of membranous structures embedded w/in the bony labyrinth

aka the membrane on top of boy labyrinth - both occupy same space

Question 24

where is endolymph found and what is it’s highest component

Answer 24

membranous labyrinth

high K content

Question 25

describe the vestibular organ

Answer 25

sensory structures that respond to changes in position of the head compared to gravity

Question 26

contents of the vestibular organ

Answer 26

maculae of saccule utricle cristae ampullares of the semicircular canals

Question 27

macula epithelium

Answer 27

support cells = columnar vestibular hair cells - not real hair but stereocilia

Question 28

where are vestibular hair cells found

Answer 28

in the maculae of the vestibular organ

Question 29

describe vestibular hair cells

Answer 29

not hair but stereocilia attached to a plate hair cells are in contact w/ afferent nerve endings

Question 30

describe the otolithic membrane of the _______ organ

Answer 30

vestibular organ gelatinous layer containing otoliths has vestibular stereocilia

Question 31

what is the functions of otoliths

Answer 31

are calcium carbonate crystals overlying the epithelium of the otolithic membrane they are displaced by head mvts and this relays sensory impulses

Question 32

epithelium of cristae ampullares

Answer 32

supporting cells = columnar similar hair cells as found in maculae

Question 33

cristae ampullares -- cupula

Answer 33

a similar gelatinous layer as the otolithic membrane but does not contain crystals but does contain fluid

Question 34

how do head mvts effect the cristae ampullares

Answer 34

mvt creates shear forces in the cupula forces between semicircular ducts that contain fluid displaced fluid causes bending in stereocilia = sensory impulses

Question 35

contents of the auditory organ

Answer 35

``` cochlear duct scala vestibuli scala tympani vestibular memb. basilar memb. stria vascularis organ of corti ```

Question 36

the cochlear duct is also called

Answer 36

scala media

Question 37

the cochlear duct divides the cochlea into ?

Answer 37

scala vestibuli and scala tympani

Question 38

the vestibular membrane forms the _____ of the auditory organ and the basilar membrane forms the ______ .

Answer 38

roof floor

Question 39

the stria vascularis forms the ______ aspect of the auditory organ, and helps form ?

Answer 39

lateral aspect forms endolymph

Question 40

the organ of corti lies on the _____ ______ of the auditory organ

Answer 40

basilar membrane

Question 41

stria vascularis

Answer 41

lateral wall of cochlear partition highly vascularized responsible for production and composition of endolymph

Question 42

the organ of corti contains inner and outer ____ cells.

Answer 42

hair cells

Question 43

the tectorial membrane is part of the

Answer 43

organ of corti