Special Senses - Ear

Question 1

Structures

Outer (external) ear

Answer 1

• Pinna
• External auditory canal

Question 2

Structure

Middle ear (ossicles) for hearing)

Answer 2

• Tympanic membrane
• Malleus (hammer)
• Incus (anvil)
• Stapes (stirrup)

Question 3

Structure

Inner ear (labyrinth)

Answer 3

• Mechanoreceptor for hearing and balance
• Vestibular apparatus
• Semicircular canals
• Cochlea
• Organ of Corti

Question 4

Funtion of External and middle section of the ear

Answer 4

• Conduct sound waves toward the inner ear
• hearing only

Question 5

Funtion of inner ear

Answer 5

Both hearing and balance

Question 6

Middle ear

Effect of sound waves on the ear

Answer 6

1. Sound waves vibrate tympanicmembrane
2. Auditory aussicles vibrate.Amplification
3. Stapes connected to oval window,sends vibrations into cochlea
4. Pressure wave pushes on basilar membrane of cochlea duct. Energy wavesdissipate at round window
5. Hair cells bend, transmission of signal
6. Neurotransmitter release activates sensory neurones, action potentials to brain.

Question 7

Inner ear

Cochlea

Answer 7

• Transmitts vibration from oval window and alows the release from the round window
• Attached to chamber regions

Question 8

Inner ear

Semicircular canals

Answer 8

• Detects movement in the ears in 3 diffrent regions
• A right angles to eachother
• Gives information about balance

Question 9

inner ear

Vestibule

Answer 9

• Information about equalibrium and the movement of fluid in the ear

Question 10

Liquids in the 3 bony chambers

Answer 10

• Perilyph and endolyph depending on the regions of the ear

Question 11

2 canals of the cochlea

Answer 11

• Extends from the oval
  window to the apex of the
  cochlea.
• From the apex back to the
  round window

Question 12

Basilar membrane

Answer 12

• Inside lining of the channel of the cochlea
• moves/vibrates when sound waves in periplymph move

Question 13

Middle cochlear cannal

Organ of Corti

Answer 13

• Specialised sensory hair cells stereocilia
• Seated on basilar membrane
• Reach to tectorial membrane
• Base of Hair cells attached to
  neuron
• Fluid surrounding is the endolymph

Question 14

Soundwaves effect on organ of corti

Answer 14

• Hair cells move due to pressure waves that sit on baseliar membrane between and Tectorial Membrane
• The BM moves and the TM is ridgid
• The stereocilia to bend the causes receptor to depolarise (mechanoreceptors)

Question 15

In equalibrium

Vestibular apparatus

Answer 15

• Static with no movement duiing equalibrium

Question 16

Maculae

Answer 16

• Hair cells, tips embedded in
  gelatinous mass weighed down by
  otoliths

Question 17

Otoliths

Answer 17

• Protein and calcium
  carbonate
• Moves in relation to gravity bending hairs
• When upright they don’t move but hairs bend when tilted
• Depolarises receptor cells and action potentials in associated nerurons travel to brain about head position

Question 18

Semi circular canals

Answer 18

• 3 right angular canals in 3 planes that cause rotational acceleration

Question 19

Ampula

Answer 19

• Hair cells embedded in jelly cupula
• Floats in endolymph

Question 20

Movement of endolymph in response to the dynamic equalibrium

Answer 20

• Endolymph tends to move in opposite direction
• Cupula and steroclia on hair cells bend
• Leads to action potential from Vestibulocochlear nerve to
  cerebellum