Module 6: Auditory system

Question 1

Structure and function of the outer ear

Answer 1

Auicule (pinna) - sound localisation and ear canal

Question 2

Structure and function of the middle ear

Answer 2

Tympanic membrane (ear drum) > cochlea. Ossicle bones: malleus, incus, stapes
Key functions:
the ossicle bones transmit vibrations through inner ear.
pressure equalisation due to esutachian tube (connects nasopharynx-middle ear)

Question 3

Structure and function of the inner ear

Answer 3

Structure: cochlea, a helical bony canal, consisting of three fluid-filled channels: scala media, scala tympani, scala vestibuli
Function: maintain equalibrium, sensory information outputted via cochleas to brain

Question 4

Mechanism of hearing

Answer 4

1. sound is a pressure wave entering the auditory canal, it makes the tympanic membrane move - alterations high and low pressure
2. At the tympanic membrane the wave will transform into a vibration, compression cycle > push on the membrane and ossicles, low pressure > pull on ossicles.
3. Amplification of the signal from the tympanic membrane across the ossicles to the oval window
4. vibration of fluid
5. pressure waves is determined by the changes in amplitude and frequency

Question 5

The inner hair cells are responsible for

Answer 5

transforming the vibrations in fluid into action potentials

Question 6

The outer hair cells act as

Answer 6

act as a cochlea amplifier.

Question 7

What are the three fluid-filled chambers of the cochlea?

Answer 7

• Scala vestibuli
• Scala media
• Scala tympani

Question 8

What is the Organ of Corti and where is it located?

Answer 8

sensory structure on the basilar membrane containing hair cells that transduce mechanical sound into neural signals.

Question 9

Where does sound enter and exit the cochlea?

Answer 9

Enters: Through the oval window (via stapes).

Exits: Through the round window.

Question 10

What causes movement of the basilar membrane?

Answer 10

Pressure waves in perilymph created by stapes movement at the oval window.

Question 11

What are the 5 established taste modalities?

Answer 11

Sweet (sugars),
Umami (amino acids),
Salty (NaCl),
Bitter (alkaloids),
Sour (acids).

Question 12

What type of receptors are used in taste?

Answer 12

Chemoreceptors

Question 13

What are the TWO main neurotransmitters released by taste receptor cells?

Answer 13

ATP and Serotonin.