The ear

Question 1

Outer Ear
-what is the pinna? what is it’s function?
-what is the auditory cancal, and what does it produce?
-where does the outer ear end?

Answer 1

-the pinna is the external ear and it colects sound and funnels it down the canal
-the canal is a narrow tube that concentrates sound, and it produces earwax
-tympanum

Question 2

Middle Ear
-where does it begin
-what are the 3 bones attached to the tympanum. Where are they found?

Answer 2

-tympanum
-ossicles, they are found in an air filled chamber

Question 3

Function of middle ear
What does it convert sound energy into?
-what happens when sound waves hit the tympanum
-what does the last ossicle do

Answer 3

-mechanical energy
-vibrations result and move through the ossicles
-the last one strikes an inner membrane called the oval window on the cochlea

Question 4

Function of middle ear
what does it do to the sound as it moves towards the inner ear?
-how is energy concentrated, and what does this do to the force of movement onto the oval window?

Answer 4

-it is amplified
-it is concentrated from the large tympanum to the small oval window, triple the force of movement

Question 5

Function of middle ear
Protection from what?
-what do muscles do in loud sounds
-what is pulled away from the oval window, and what does it result in

Answer 5

excessive noise
-restrict movement of the ossicles
-stapes, decreased intensity on the cochlea

Question 6

Function of middle ear
equalizing what?
-what are the conditions for the tympanum to vibrate freely
-what does the eustacian tube do?

Answer 6

air pressure
-equal pressure on both sides
-opens and closes to equalizing air pressure

Question 7

Inner ear
-3 parts and their basic function

Answer 7

1. cochlea- hearing
2. semicircular canals-balance when moving
   3.vestibule: balance when stationary

Question 8

Cochlea
-what cells does it contain (specifically located where), and what do they do
-what direction do the vibrations of ossicles push the oval window, and what does that cause
-how is pressure relieved after
-what do the hair cells sense
-what can the hair cells distinguish between

Answer 8

-specialized hair cells in the organ of corti
-inwards which causes the oval window to be pushed inwards and cause fluid movement
-the round window is pushed outwards by the fluid
-bending of the cilliar and synapse with the nerve fibres of auditory nerve
-between frequency and amplitude

Question 9

Frequency
-what do high vs low do t the hair cells

Answer 9

high: stimulate hair cells closest to the oval window
low:stimulate hair cells farthest from the oval window

Question 10

Amplitutde
-what happens when the noise is louder

Answer 10

greater pressure on the fluid in the cochlea on the hair cells

Question 11

Semicircular canals
-3 of what
-what do their sensitive hair cells detect
-function

Answer 11

-fluid filled bone chambers
-motion of fluids in the canals and synapse with the vestibules
-detect change in motion, dynamic equilibrium