Hearing, Taste, and Smell

Question 1

What is the auricle? its function?

Answer 1

the visible part of the ear, it collects and amplifies sound

Question 2

What is the external auditory meatus? function?

Answer 2

the auditory canal. it is an air filled space that transmits sound to tympanic membrane

Question 3

What is the tympanic membrane? function?

Answer 3

the ear drum, it converts sound waves to mechanical vibrations

Question 4

How are the mechanical vibrations transmitted to the oval window into the inner ear?

Answer 4

via the tympanic ossicles

Question 5

What are the 3 tympanic ossicles?

Answer 5

-mallus, incus, stapes

Question 6

What is the function of the auditory tube (eustachian tube)

Answer 6

connect middle ear to nasopharynx. it is normally collapsed but will open to equalize pressure

Question 7

What are the two skeletal muscles associated with the ossicles?

Answer 7

-tensor tympani
-stapedius

Question 8

What are the 3 components that make up the boney labyrinth of the inner ear?

Answer 8

-Cochlea
-Vestibule
-Semicircular canals

Question 9

What is the outer boney labyrinth filled with

Answer 9

perilymph

Question 10

What is the inner membranous labyrinth filled with?

Answer 10

endolymph

Question 11

What are the regions of the inner membranous labyrinth that are specialized sensory regions?

Answer 11

-Cristae amplularis (SC canals)
-Maculae (saccule and utricle)
-Spiral organ of corti (Cochlea)

Question 12

How do the sensory hair cells of the specialized sensory regions transduce signal?

Answer 12

-mechanical displacement of stereocilia
-depolarization
-opening of K channels, high k in endolymph favors movement into cell
-voltage gated ca channels open
-glutamate released

Question 13

What is the modiolus?

Answer 13

the bony projection that runs through the middle of the cochlear spiral

Question 14

what creates endolymph?

Answer 14

the lining cells of the membranous labyrinth (stria vasculari)

Question 15

Explain how auditory signal is transduced once it is already in the middle ear

Answer 15

The mechanical vibration created by the ossicles travel along the basalar membrane, this causes the sensory hair cell stereocilia to move ultimately causing the release of glutamate onto the dendrites of the bipolar neurons of the cochlear nerve, the central axons then come together in cochlear nerve and then leave

Question 16

What are the sensory regions of the saccule and utricle?

Answer 16

maculae saccili and maculae utriculi

Question 17

What portion(s) of the inner ear are responsible for vestibular signal transduction?

Answer 17

the vestibule (saccule and utricle) and the semicircular canals

Question 18

Explain signal transduction of vestibular signal, rotational movement

Answer 18

similar to auditory but the stereocilia of the sensory hair cells are embedded in the cupula, so once the head moves the, the endolymph moves causing the stereocilia to move, which causes firing and then the vestibular nerve endings around the hair cells are stimulated

Question 19

What are the 5 tastes detected?

Answer 19

salty, sweet, sour, umami, bitter

Question 20

Where are taste buds located?

Answer 20

gustatory lingual papilla, soft palate, epiglottis, and pharynx

Question 21

Describe signal transduction for salty tastes

Answer 21

-Na from food enters na channel, depolarization, influx of Ca releases NT

Question 22

Describe signal transduction for sour tastes

Answer 22

H+ blocks K channel, k can’t leave, depolarization of cell, influx of ca, NT released

Question 23

Describe signal transduction for bitter tastes

Answer 23

bitter substance binds, conformational change, g protein cascade to activate phospholipase C, IP3 generated, IP3 causes Ca to be released from intracellular stores, NT released

Question 24

Describe signal transduction for sweet tastes

Answer 24

sweet binds, conformational change, g protein cascade to activate adenylate cyclase, catalyzes conversion of ATP to cAMP, cAMP activates protein kinase, closes K channel, depolarization, Ca influx, NT release