Ear

Front 1

outer ear

Back 1

pinna
external auditory meatus

Front 2

pinna

Back 2

outer ear stucture
fleshy ear structure made of elastic cartilage on the side of the head. directs sound into audtiory canal

Front 3

external auditory meatus

Back 3

outer ear stucture
external opening of the ear.
supported by temporal bone and fibrocartilage
contains ceruminous and sebacious glands

Front 4

middle ear

Back 4

tympanic membrane
tympaic cavity
auditory tube
auditory ossicles

Front 5

tympanic cavity

Back 5

open air space medial to the eardrum.
contains all the contents of the middle ear
located in temporal bone

Front 6

tympanic membrane

Back 6

eardrum
connective tissue membrane that vibrates freely in response to sound
highly sensative to pain

Front 7

auditory tube

Back 7

a passageway from pharynx (throat) to tympanic cavity
normaly closed
opens when yawing or swallowing
allows throat infections to spread to middle ears

Front 8

auditory ossicles

Back 8

smallest bones of the body
connect the tympaic membrane to the inner ear
1st-malleus- hammer
2nd- incus- anvil
3rd- staples- stirrup

Front 9

inner ear (cochlea)

Back 9

oval window
scala vestibuli
scala tympani
cochlear duct
round window
cochlear nerve

Front 10

oval window

Back 10

opening where inner ear begins

Front 11

bony labyrinth

Back 11

maze of temporal bone passageways that houses the inner ear

Front 12

membranous labyrinth

Back 12

membranous maze of tubes in the bony labyrinth that contains fluid and sensory hair cells
filled with endolymph

Front 13

perilymph

Back 13

cushion of fluid inbetween the bony and membranous labyrinth similar to CSF

Front 14

endolymph

Back 14

fluid in membranous labrinth similar to intracellular fluid
(high in potassium)

Front 15

cochlea

Back 15

organ of hearing
coiled tube that arises form the anterior side of the vestibule
consists of three fluid filled chambers:
1. scala vestibuli
2. scala tympani
3. cochlear duct (scala media)

Front 16

scala vestibuli

Back 16

superior chamber of cochlea
filled with perilymph
begins near oval window, ends near apex

Front 17

scala tympani

Back 17

inferior channel of cochlea
filled with perilymph
starts at apex, ends at round window

Front 18

cochlear duct (scala media)

Back 18

middle chamber of cochlea makes up triangular space
filled with endolymph
-seperated from scala vestibuli by vestibular membrane
-seperated from scala tympani by basilar membrane
contains the organ of corti

Front 19

vestibular membrane

Back 19

thin membrane seperates cochlear duct from scala vestibuli

Front 20

basilar membrane

Back 20

thicker membrane seperartes cochlear duct from scala tympani

Front 21

organ of corti

Back 21

found in the cochlear duct on the basilar membrane
-converts vibrations into nerve impulses
*has an epithelium composed of hair cells and supporting cells
*on top of hair cells is a gelatious tectorial membrane

Front 22

hair cells

Back 22

receptor cells with stiff microvili called stereocilia
covered by tectorial membrane
four rows of these are set in the basilar membrane
only inner most perceive sound

Front 23

stereocilia

Back 23

long stiff microvili found on hair cells

Front 24

tectorial membrane

Back 24

gelatinous membrane on stereocilia

Front 25

physiology of hearing

Back 25

transmisssion from eardrum to hair cells
1. sound waves vibrate the tympanic membrane, which causes the ossicles to vibrate. ossicles focuse vibrations on oval window, which causes the perilymph of the scala vestibuli to vibrate.
2. vibrations are passed through the vestibular membrane into the cochlear duct. endolymph than carries vibrations to the basilar membrane, where the hair cells are.
3. movement of basilar membrane cause stereocells to bend because they are imbeded in tectorial membrane. this opens mechanicaly gated ion channels at the tips of setereocilia to open, allowing potasium in, depolarizing the hair cell. while depolrized, the hair cells realease neurotransmitters onto dendrites of vestiblocochlear nerve
4. sound vibrations continue through the basilar membrane into the scala tympani, and to the round window
5. sensory neurons for hair cells transmit up vestiblocochlear nerve to the pons. second order neurons go to inferior colliculus of corpora quadrigemina. third order neurons lead to thalmus. fourth order to primary auditory cortex of temporal lobe

Front 26

vestliblocochlear

Back 26

nerve from hair cells to pons

Front 27

equilibrium

Back 27

coordination, balance, and orientation in 3 dimesional space
static equilibrium
dynamic equilibrium

Front 28

inner ear (vestibule)

Back 28

semicircular canals
amullae
utricle
saccule
vestibular nerve

Front 29

static equilibrium

Back 29

perception of the orientation of the head when body is stationary

Front 30

dynamic equilibrium

Back 30

perception of motion or acceleration (linear, and angular)
detected by saccule and utricle

Front 31

linear acceleration

Back 31

a change in velocity in a staright line
detected by saccule and utricle

Front 32

angular acceleration

Back 32

change in the rate of rotation
detected by semicurcular canals

Front 33

saccule

Back 33

anterior chamber of vestibule
contains endolymph, hair cells, and vertical macula

Front 34

utricle

Back 34

posterior chamber of vestibule
contains endolymph, hair cells, and horizontal macula

Front 35

macula

Back 35

sensory organ found in saccule and utricle
made of hair cells with 40-70 stereo cilia
stereocilia embended in otolithic membrane
*movement of the head sends the brain signals from macula of both chambers in both ears

Front 36

otolthic membrane

Back 36

gelatinous membrane on tope of stereo cilia in saccule and utricle
weighted by protein-calcium carbonate granules called otoliths

Front 37

otoliths

Back 37

protein-calcium carbonate grannules that give weight to otolithic membrane
give wieght and inertia to membrane to enhance sense of gravity and motion

Front 38

macula utricle

Back 38

lie horizontaly in the macula
detects tilt of head
*otolithic membrane lags behind when body accelerates , and moves foreward during deceleration, giving sense of ovement in a stright line

Front 39

macula sacculi

Back 39

verticle macula that respond to verticle acceleration and deceleration.
moving up, the otolicic membrane pulls down on the hairs
when you stop, otolithic membrane keeps going for a moment bending the hairs
makes brain aware of verticle motion

Front 40

semicircular ducts

Back 40

3 canals filled with endolymph that sense angular acceleration
housed in semicircular canals of temporal bone
anterior, posterior and lateral
different ducts are stimulated by rotation of head in different planes
each ducts open into the utricle.

Front 41

ampulla

Back 41

dilated sac at one end of each duct
contains hair cells and crista ampullaris
hair cells imbed into cupula

Front 42

crista amularis

Back 42

sensory organ in the ampula made of hair cells with stereocilia embended into cupula

Front 43

cupula

Back 43

gelatinous cap that extends from crista tot he roof of the ampula

Front 44

turning

Back 44

turning in any direction causes endolymph to lag behind in the ducts. this moves the cupula and bends the sterocilia, stimulating the hair cells

Front 45

semicircular duct projection pathway

Back 45

1st- vestiblocochlear nerve to pons or cerebellum
2nd- to cervical spinal cord
3rd- to cranial nerves that controls eyes, head, and neck movements