A&P2 Hearing (physiology)

Sound Wave pitch is what part of the wave? What are we measuring if we talk amplitude of waves?

Pitch: determined by wave frequency (Hz)

Amplitude: determined by loudness (db)

Trace a sound wave from outside the outer ear to action potential. This will be 10+ steps.

1. Sound wave enters the outer ear

2. Vibrations reach tympanic membrane

3. Transfers vibrations to ossicles

4.stapes move to oval window

5. pressure waves move perilymph in cochlea

6. Basilar membrane vibrates

7. Hair cells bend causing ion opening

8. depolarization of hair cells releasing neurotransmitters

9. auditory nerve fibers transmits electrical signals

10. signal processed in brain

11. signal relayed to thalamus

12. reaches auditory cortex

13. sound is perceived by brain

14. sound

What is the purpose of the oval window?

Transmits sound vibrations from middle ear (ossicles) into the inner ear (cochlea) acting as bridge converting mechanical vibrations into pressure waves in cochlear fluid allowing auditory system to process sound in brain

What is the purpose of the round window?

pressure release valve

Where are the hair cells in hearing located? What micronutrient depolarizes them?

The inner and out hair cells are located in the Organ of Corti along basilar membrane in cochlear duct depolarized by the micronutrient K+

Does the scala vestibule border the oval or round window? How about the scala tympani?

Scala Vestibuli: borders oval window

Scala Tympani: borders round window

Where in the cochlea is high pitch sounds received, low pitch? P.606

High pitched: base of cochlea near oval window

Low pitch: the tip of cochlea at the apex

What is nerve deafness? What is conduction deafness?

Nerve deafness: inner ear hair cells or auditory nerve damaged affecting ability to hear and is permanent

Conduction deafness: outer or middle ear blockage of sound that is reversible