Auditory System

Question 1

Auditory Anatomy

Answer 1

1. External Ear - pinna/ tympanic membrane
2. Middle Ear - malleus/incus/stapes/oval&round windows
3. Inner Ear - semicircular canals/cochlea

Question 2

Auditory Signalling

Answer 2

1. sound waves hit tympanic membrane and become vibrations
2. vibrations move through the middle ear to the oval window
3. vibrations create fluid waves in the cochlea
4. waves push on cochlear duct membranes which make hair cells bend, opening ion channels
5. ion channels opening creates a signal that alters nt release
6. nt’s travel onto sensory neurons that create an AP through the cochlear nerve
7. energy leaves the cochlear duct, entering the tympanic duct to dissipate through the round window

Question 3

Organ of Corti

Answer 3

• inside the cochlear duct
• wave pressure moves the hair cells one direction which triggers K+ to enter (depolarization) because of the tectorial membrane

Question 4

Detecting Frequency

Answer 4

• higher frequency doesnt travel as far in the cochlear membrane

Question 5

Volume

Answer 5

amplitude of a sound wave (dB)

Question 6

Pitch

Answer 6

frequency of a sound wave (Hz)

Question 7

Perilymph filled ducts

Answer 7

Vestibular and Tympanic ducts

Question 8

Endolymph filled ducts

Answer 8

cochlear duct

Question 9

EPSP of hair cells ion flow

Answer 9

potassium enters hair cell and depolarizes, causing nt release