Hearing/Ears & Balance

Question 1

What is the frequency range that humans can hear from?

Answer 1

20-20,000 hertz, hear mostly from 1000-3000 hertz though

Question 2

What is amplitude?

Answer 2

Amplitude is the intensity of the sound wave. The more intense the push of air on the eardrum, the more intense the action potential response
-Amplitude is measured in decibels, 60 decibels is normal conversation and 120 decibels is damaging to eardrums (rocket launches)

Question 3

Structure of the outer ear

Answer 3

contains the auricle or pinna and external auditory canal. These structures work to channel the sound waves into the external auditory canal and then into the tympanic membrane or the ear drum

Question 4

Middle ear structure

Answer 4

This contains three auditory ossicles that hit against each other to amplify the sound that came in from the eardrum. The structures are the malleus, incus, and stapes or the hammer, anvil, and stirrup. This cavity is air filled and the sound waves are channeled to the oval window.
-There is also an eustachian tube in this location that connects with the pharynx and regulates pressure in the ears

Question 5

Inner ear structure

Answer 5

Once the sound waves have entered the inner ear, they enter the boney labyrinth which has three parts; the vestibular apparatus, the semicircular canals, and the cochlea. Inside of the cochlea are scala vestibuli, the scala tympani, and the round window. these two tubes are filled with perilymph which is a fluid similar to extracellular fluid. Then theres the cochlear duct which is filled with fluid similar to intracellular fluid. Within this duct is the Organ of Corti which transfers the mechanical sound waves into electrical signals.

Question 6

How is sound converted to electrical action potentials

Answer 6

The sound wave travels through the ear, to the cochlea, where the sound waves resonate with different lengths of hair which then open up mechanically gated ion channels and depolarize the neurons and send action potentials up the cochlear nerve

Question 7

Vestibular apparatus

Answer 7

deals with balance, the semicircular canals have hair like cells in them and fluid and they can detect movement of the head. Sensory organs called otolith organs detect the movement