The Ear

Question 1

What are the divisions of the ear?

Answer 1

• outer ear (pinna and auditory glands)
• middle ear - tympanum (border), semicircular, canal and cochlea
  
  • fluid filled

Question 2

Describe the pinna

Answer 2

• visible flap of the year
• focuses sound

Question 3

Describe the auditory canal

Answer 3

• 2.5cm long tube
• leads from pinna to tympanum (ear drum)
• amplifies sound waves
• hair and ear wax prevent foreign materials from going dweller into the ear

Question 4

Describe the tympanum

Answer 4

• ear drum
• round, elastic structure
• vibrates in response to sound waves

Question 5

Describe the ossicles

Answer 5

• three small, interconnected bones (smallest bones in body)
• use lever action to emphasize sound (small movement in one results in larger movement in next
• the three bones are malleus, incus and stapes (in order from external to internal ear)

Question 6

Describe the oval window

Answer 6

• membrane covered opening to inner ear
• 15-30 times smaller than tympanum (so amplifies sound)

Question 7

Describe the Eustachian tube

Answer 7

• connects middle ear to throat
• allows air pressure to equalize (between middle ear and external environment

Question 8

Describe semi-circular canals and vestibule

Answer 8

Contains sensors for balance

Question 9

Describe the cochlea

Answer 9

• contains structures for hearing
• mechanical energy (sound waves) converted into chemical energy

Question 10

What are the parts of the cochlea?

Answer 10

• organ of hearing, made of the following :
  
  • basilar membrane - mechchanoreceptors (hair cells) attached to the
  • stereocilla - fine projections of hair cells
  • tectorial membrane - stereocilla imbedded here