10.4: Equilibrium and Hearing

Question 1

Name for eardrum

Answer 1

tympanic membrane

Question 2

auricle

Answer 2

aka pinna; most prominent feature of the outer ear

Question 3

external acoustic meatus

Answer 3

1. aka auditory canal 2. passage through the temporal bone leading to the eardrum 3. S-shaped course for about 3 cm 4. lined with skin 5. possesses ceruminous and sebaceous glands

Question 4

cerumen

Answer 4

1. aka earwax 2. secretions of ceruminous and sebaceous glands 3. waterproofs the canal, inhibits bacterial growth, and keeps eardrum pliable

Question 5

tympanic cavity

Answer 5

tiny air-filled chamber medial to the tympanic membrane; 2-3 mm wide

Question 6

malleus

Answer 6

attached to the inside of the tympanic membrane

Question 7

incus and stapes

Answer 7

two middle ear bones

Question 8

pharyngotympanic tube

Answer 8

1. aka auditory or eustachian tube 2. regulates air pressure; connected to pharynx 3. normally flattened and closed 4.when we yawn or swallow, it opens, allowing air to enter/leave the tympanic cavity

Question 9

muscles of middle ear

Answer 9

stapedius (stapes) and tensor tympani (malleus contract and inhibit movement of bones, preventing overstimulation

Question 10

ottis media

Answer 10

middle-ear infection common in children because auditory tubes are short/horizontal for microbes to travel from throat if untreated, can cause meningitis

Question 11

tympanostomy

Answer 11

puncturing the tympanic membrane and inserting a tiny drainage tube to drain fluid from the middle ear

Question 12

primary function of inner ear

Answer 12

transform mechanical energy/vibration to nerve energy

Question 13

bony labyrinth

Answer 13

maze of passages in the temporal bone consists mostly of membranous labyrinth (complex of fluid-filled chambers and tubes)

Question 14

endolymph

Answer 14

similar to intracellular fluid; fills the membranous labyrinth

Question 15

perilymph

Answer 15

similar to cerebrospinal fluid; surrounds the membranous labyrinth

Question 16

oval window

Answer 16

opening that marks the beginning of the inner ear; attached to stapes

Question 17

vestibule

Answer 17

on the side opposite side of the oval window as the stapes; filled with endolymph

Question 18

saccule and utricle

Answer 18

two pouches within the vestibule; filled with endolymph contain patches of epithelium called macula

Question 19

vestibular apparatus

Answer 19

organs of equilibrium saccule, utricle, and semicircular ducts

Question 20

macula

Answer 20

patch of epithelium; composed of sensory hair cells and non sensory supporting cells; in saccule and utricle

Question 21

stereocilia

Answer 21

hairlike microvilli on a hair cell’s apical surface

Question 22

otolithic membrane

Answer 22

layer of gel overlying the macula contains granules of protein and CaCO3 called otoliths

Question 23

otoliths

Answer 23

give the otolithic membrane added weight and inertia, enhancing ability to stimulate hair cells when body moves

Question 24

semicircular ducts

Answer 24

1. detects head rotation; filled with endolymph 2. each duct has a bulb at its base called the ampulla

Question 25

crista ampullaris

Answer 25

3. mound of sensory epithelium within the ampulla 4. composed of hair cells and supporting cells

Question 26

cupula

Answer 26

gelatinous cap copping the crista ampullaris

Question 27

Route from cranial nerve VIII

Answer 27

to pons of brainstem from pons to: 1. primary somatosensory cortex, where one becomes conscious of head movements 2. spinal cord; generate signals to muscles for posture/balance 3. cerebellum; motor coordiation 4. midbrain nuclei; activate eye movements to compensate for head movements

Question 28

Hearing

Answer 28

awareness of sound; cochlea

Question 29

cochlear duct

Answer 29

divide the fleshy tube, cochlea, into a triangular space, filled with endolymph and two larger spaces called scalae (filled with perilymph)

Question 30

basilar membrane

Answer 30

separates cochlear duct and lower scala; thicker than separation of upper scala and cochlear duct; platform for sensory cells of the cochlea

Question 31

spiral organ

Answer 31

aka acoustic organ, organ of Corti provides cochlea with sensory hair cells and supporting cells

Question 32

cochlea inner hair cells

Answer 32

~3500 hair cells with 50-60 each row

Question 33

cochlea outer hair cells

Answer 33

~20000 hair cells farther away from bony core of the cochlea; arranged in 3 rows

Question 34

tectorial membrane

Answer 34

gelatinous membrane just above the hair cell stereocillia; anchored to the core of the cochlea

Question 35

loudness in sound

Answer 35

amplitude

Question 36

frequency in sound

Answer 36

low or high pitch

Question 37

binaural hearing

Answer 37

ability to localize sounds in space; midbrain

Question 38

primary auditory cortex

Answer 38

in the temporal lobe of the cerebrum signals relayed from the thalamus to ___ where we become consciously aware of the sound

Question 39

Hearing

Answer 39

Cochlear duct

sensory organ (spiral organ)

gelatinous membrane (tectorial)

Question 40

static equilibrium organs

Answer 40

saccule/utricle

sensory organ (macula)

gelatinous membrane (otolithic)

Question 41

Rotation organs

Answer 41

semicircular duct

sensory organ (christae)

gelatinous membrane (cupula)