12.3 Mechano and chemoreceptions

Question 1

Mechanoreceptors

Answer 1

specialized sensory receptor cells for both hearing and balance

Question 2

Sound waves

Answer 2

small fluctuations in the air pressure

Question 3

Mechanoreceptors in the ear

Answer 3

Convert the energy of sound waves in the inner ear into the electrochemical energy the brain perceives as sound.

Question 4

Outer ear

Answer 4

• pinna

- auditory canal

Question 5

Pinna

Answer 5

the outside flap of the ear

- made of ear and skin cartilage shaped in a way that enhances sound vibrations and focuses them into the ear.

Question 6

auditory canal

Answer 6

a tube that leads to the eardrum in the middle ear
amplifies sound waves, effectively making sounds louder.
hairs as well as earwax secreted by the glands in the auditory canal prevents dust, insects bacteria and other foreign material.

Question 7

Middle ear

Answer 7

air filled space that is bordered on one side by the tympanum.

ossciles

Question 8

Tympanum

Answer 8

round, elastic structure that vibrates in response to sound waves

• its vibrations are passed on and applied by the neighbouring ossicles.

Question 9

Ossicles

Answer 9

• three tiny interconnected bones in the middle ear
• each bone acts as a lever for the next so that a small movement in one results in a larger movement in the next,

strength of vibrations is amplified.
the stapes concentrates vibrations into the membrane covered opening in the wall of the inner ear called the oval window.

Question 10

oval window

Answer 10

beginning of inner ear

vibrated by stapes

Question 11

Eustachian tube

Answer 11

Connects the middle ear to the throat

Allows air pressure to equalize when there is a difference in air pressure within and outside the middle ear

Question 12

inner ear

Answer 12

semicircular canals
vestibule
cochlea

Question 13

semicircular canal and vestibule all: _______ while the cochlea____

Answer 13

contain sensors for balance

is used for hearing

Question 14

Cochlea

Answer 14

where mechanical energy of sound is converted into the electrochemical impulse that are transmitted to the brain.

contains organ of corti

Question 15

Organ of corti+ how it works

Answer 15

part of the cochlea
the organ of hearing

along the base of corti is the basilar membrane where hair cells are attached, The top end of the hair cells are attached tp the tutorial membrane. When the stapes strikes the oval window, this vibrates the window and creates pressure waves in the fluid of the cochlea. The pressure wave makes the basilar membrane move up and down causing the hair cells to bend against the tectorial membrane. The hair cells which synapses with the nerve fibres of the auditory nerve sense the bending and relay message to nerves.

Question 16

High frequencies in the organ of corti:

Answer 16

strongly stimulate the hair cells that are closet to the oval window

Question 17

Low frequencies in the organ of corti:

Answer 17

Strongly stimulate the hair cells that are farthest from the oval window

Question 18

Semicircular canals

Answer 18

• contain mechanoreceptors that detect head and body rotation.
• three fluid filled loops
  the connecting part of the three loop have hair cells. When the head bends, the fluid in the semicircular canals moves and bends the stereocilia on the hair cells