Auditory System

Question 1

Describe the main functions of the ear.

Answer 1

The ear is responsible for hearing and balance, with different structures dedicated to each function.

Question 2

Explain the role of fluids in the ear.

Answer 2

Fluids must be moved to stimulate the mechanoreceptors located in the internal ear for both hearing and balance.

Question 3

Define the three major areas of the ear.

Answer 3

The ear consists of the external ear (hearing only), middle ear (tympanic cavity, hearing only), and internal ear (hearing and equilibrium).

Question 4

How does the auricle (pinna) contribute to hearing?

Answer 4

The auricle is a shell-shaped structure that funnels sound waves into the auditory canal.

Question 5

What is the function of the tympanic membrane (eardrum)?

Answer 5

The tympanic membrane vibrates in response to sound and transfers sound energy to the bones of the middle ear.

Question 6

Describe the structure and function of the middle ear.

Answer 6

The middle ear is a small, air-filled cavity that contains the auditory ossicles and connects to the nasopharynx via the pharyngotympanic tube.

Question 7

Explain the importance of the pharyngotympanic tube.

Answer 7

The pharyngotympanic tube equalizes pressure in the middle ear cavity with external air pressure, allowing the tympanic membrane to vibrate efficiently.

Question 8

What are the auditory ossicles and their roles?

Answer 8

The auditory ossicles are three small bones (malleus, incus, stapes) that transmit sound vibrations from the tympanic membrane to the inner ear.

Question 9

How do the malleus, incus, and stapes interact?

Answer 9

The malleus articulates with the incus, which in turn articulates with the stapes, allowing sound transmission through synovial joints.

Question 10

Describe the main functions of the ear.

Answer 10

The ear is responsible for hearing and balance, with different structures dedicated to each function.

Question 11

Define the three major areas of the ear.

Answer 11

The ear consists of the external ear (hearing only), middle ear (tympanic cavity, hearing only), and internal ear (hearing and equilibrium).

Question 12

Explain the role of fluids in the ear.

Answer 12

.Fluids must be moved to stimulate the mechanoreceptors located in the internal ear for both hearing and balance.

Question 13

How does the auricle (pinna) contribute to hearing?

Answer 13

The auricle is a shell-shaped structure that funnels sound waves into the auditory canal.

Question 14

What is the function of the tympanic membrane (eardrum)?

Answer 14

The tympanic membrane vibrates in response to sound and transfers sound energy to the bones of the middle ear.

Question 15

Describe the structure and function of the middle ear.

Answer 15

The middle ear is a small, air-filled cavity that contains the auditory ossicles and connects to the nasopharynx via the pharyngotympanic tube.

Question 16

Explain the importance of the pharyngotympanic tube.

Answer 16

The pharyngotympanic tube equalizes pressure in the middle ear cavity with external air pressure, allowing the tympanic membrane to vibrate efficiently.

Question 17

What are the auditory ossicles and their roles?

Answer 17

The auditory ossicles are three small bones (malleus, incus, stapes) that transmit sound vibrations from the tympanic membrane to the inner ear.

Question 18

How do the malleus, incus, and stapes interact?

Answer 18

The malleus articulates with the incus, which in turn articulates with the stapes, allowing sound transmission through synovial joints.

Question 19

Describe the external acoustic meatus.

Answer 19

The external acoustic meatus is a short, curved tube lined with skin, hairs, and glands that transmits sound waves to the eardrum.

Question 20

What happens if the pressures on both sides of the tympanic membrane are not equal?

Answer 20

If pressures are not equal, the tympanic membrane cannot vibrate efficiently, leading to distorted sounds.

Question 21

Define the epitympanic recess.

Answer 21

The epitympanic recess is the superior portion of the middle ear, located above the tympanic cavity.

Question 22

Explain the role of the mastoid antrum.

Answer 22

The mastoid antrum is a canal that allows communication between the middle ear and the mastoid air cells.

Question 23

What is the significance of the earwax glands in the external ear?

Answer 23

The earwax glands produce cerumen, which helps protect the ear canal by trapping debris and providing lubrication.

Question 24

Describe the function of the tensor tympani and stapedius muscles in the ear.

Answer 24

These muscles contract reflexively in response to loud sounds to prevent damage to hearing receptors.

Question 25

Explain the role of the trigeminal nerve and cranial nerve VII in the ear.

Answer 25

Motor input from the trigeminal nerve (V) controls the tensor tympani, while cranial nerve VII controls the stapedius.

Question 26

Define the bony labyrinth in the context of the inner ear.

Answer 26

The bony labyrinth is a system of tortuous channels and cavities that worm through the bone, divided into three regions: vestibule, semicircular canals, and cochlea.

Question 27

How is the membranous labyrinth structured within the bony labyrinth?

Answer 27

The membranous labyrinth consists of a series of membranous sacs and ducts filled with potassium-rich endolymph.

Question 28

Describe the components of the membranous labyrinth of the internal ear.

Answer 28

It includes the vestibule, semicircular canals, and cochlea.

Question 29

What are the two membranous sacs contained in the central cavity of the bony labyrinth?

Answer 29

The two membranous sacs are the saccule, which is continuous with the cochlear duct, and the utricle, which is continuous with the semicircular canals.

Question 30

Explain the function of the maculae found in the saccule and utricle.

Answer 30

The maculae are equilibrium receptor regions that respond to gravity and changes in the position of the head.

Question 31

How are the semicircular canals oriented in relation to each other?

Answer 31

The anterior and posterior canals are at right angles to each other, while the lateral canal is horizontal.

Question 32

What is the ampulla in the context of the semicircular canals?

Answer 32

The ampulla is the enlarged area of the ducts of each canal that houses the equilibrium receptor region called the crista ampullaris.

Question 33

Describe the function of the crista ampullaris.

Answer 33

The crista ampullaris contains receptors that respond to angular (rotational) movements of the head.

Question 34

Define the cochlea and its general structure.

Answer 34

The cochlea is a small spiral, conical, bony chamber that extends from the vestibule and coils around a bony pillar called the modiolus.

Question 35

What are the three chambers of the cochlea and their contents?

Answer 35

The three chambers are the scala vestibule (contains perilymph), scala media (cochlear duct, contains endolymph), and scala tympani (terminates at the round window).

Question 36

How does the scala vestibule relate to the oval window?

Answer 36

The scala vestibule abuts the oval window.

Question 37

What is the significance of the cochlear duct within the cochlea?

Answer 37

The cochlear duct houses the spiral organ (organ of Corti), which is essential for hearing.

Question 38

Describe the role of the vestibular membrane in the cochlear duct.

Answer 38

The vestibular membrane acts as the 'roof' of the cochlear duct, separating the scala media from the scala vestibuli.

Question 39

Explain the function of the stria vascularis in the cochlear duct.

Answer 39

The stria vascularis is the external wall of the cochlear duct composed of mucosa that secretes endolymph.

Question 40

Define the structure that forms the 'floor' of the cochlear duct.

Answer 40

The 'floor' of the cochlear duct is composed of the bony spiral lamina and the basilar membrane, which supports the spiral organ.

Question 41

How are hair cells arranged in the spiral organ of the cochlea?

Answer 41

The spiral organ contains cochlear hair cells arranged in one row of inner hair cells and three rows of outer hair cells.

Question 42

Do hair cells in the cochlea have a specific location relative to membranes?

Answer 42

Yes, hair cells are sandwiched between the tectorial membrane and the basilar membrane.

Question 43

Explain the connection between the cochlear branch of nerve VIII and the spiral organ.

Answer 43

The cochlear branch of nerve VIII runs from the spiral organ to the brain, transmitting auditory information.

Question 44

What is the significance of the helicotrema in the cochlea?

Answer 44

The helicotrema is the point where the scalae tympani and vestibuli are continuous with each other, allowing fluid movement.

Question 45

Describe the composition of the cochlear duct.

Answer 45

The cochlear duct is composed of the vestibular membrane, stria vascularis, and the 'floor' made up of the bony spiral lamina and basilar membrane.