Vestibular system and ears

Question 1

What are the names of the three bones in the ear canal?

Answer 1

malleus, incus and stapes

Question 2

What are the names of the two otolith organs?

Answer 2

Utricle and saccule

Question 3

What are the two main structural components of the peripheral vestibular system?

Answer 3

Semicircular canals and the vestibulum

Question 4

How many semicircular canals are present?

Answer 4

3

Question 5

What type of stimuli do semicircular canals detect?

Answer 5

Angular acceleration

Question 6

What type of stimuli do the otolith organs detect?

Answer 6

Linear acceleration

Question 7

What is the name for the special sensory epithelium of the vestibular organs?

Answer 7

Macula

Question 8

What is the name of the cells lining the semicircular canals and the vestibilum?

Answer 8

Hair cells

Question 9

What special sensory organs are located in the vestibulum?

Answer 9

Otolith organs

Question 10

What is the name for the special area within the semicircular canals that dilates slightly, where you can find the crista ampullaris?

Answer 10

Ampulla

Question 11

What part of the inner ear does the vestibulum describe, the bony or membranous labyrinth?

Answer 11

Bony

Question 12

What fluid is contained in the body labyrinth?

Answer 12

Perilymh

Question 13

What fluid is contained in the membranous labyrinth?

Answer 13

Endolymph

Question 14

What part of the inner ear does the semicircular canal describe, the bony or membranous labyrinth?

Answer 14

Bony

Question 15

What part of the inner ear does the Semicircular ducts describe, the bony or membranous labyrinth?

Answer 15

membrane

Question 16

What special sensory organs are found in the semicircular canals?

Answer 16

Crista amullaris

Question 17

What is the name for the gelatinous covering of the crista amullaris?

Answer 17

Capula

Question 18

What substances can be found in the gelatinous covering of the otolith organs?

Answer 18

Calcium carbonate

Question 19

When the head moves, and the gelatinous covering of the vestibular organs moves, what structures does this also move, which then stimulate action potentials?

Answer 19

Steriocilia

Question 20

Where in the utricle are har cells found?

Answer 20

floor

Question 21

Where in the sacule are har cells found?

Answer 21

Lateral wall

Question 22

In addition to linear acceleration forwards and backwards, what other stimuli can utricles respond to?

Answer 22

Head tilting

Question 23

With regards to the direction of motion, which way do the steriocilia bend in the vestibular organs?

Answer 23

Opposite to direction of motion

Question 24

What is the tallest steriocilia called?

Answer 24

Kinocillium

Question 25

What is the property that resists endolymph movement in the semicircular canals that is important to allow movement of steriocilia?

Answer 25

Inertia

Question 26

In what direction would the steriocilia have to bend in order to increase the rate of action potentials?

Answer 26

towards the steriocilia

Question 27

How does the bending of steriocilia elicit a nerve impulse in the vestibular nerve?

Answer 27

Bending towards the steriocilia will open K+ and Ca2+ channels causing the cell to depolarise and ions to diffuse into the cell and ultimately result in vesicles of neurotransmitters to fuse with the membrane and be released, stimulating an action potential in the neurone.

Question 28

What organ responds to static information?

Answer 28

otolith

Question 29

Which organ responds to dynamic information?

Answer 29

crista ammularis/semicircular canal

Question 30

Which tract is is involved in the contraction of postural muscles in response to changes in head position and where does it cross?

Answer 30

Vestibulospinal and it doesn't cross

Question 31

Other than sending fibres down the spinal cord, where else does the vestibular nucleus project to?

Answer 31

- fastigal nucleus in the flocullonodular lobe of the cerebellum - contralateral abducens nucleus - ipselateral oculomotor nucleus - trochlear nucleus

Question 32

Where abouts in the brain is the vestibular nucleus lie?

Answer 32

Pons and medulla

Question 33

Where abouts in the spinal cord does the vestibulospinal tract run?

Answer 33

ventral funiculus

Question 34

Via which peduncle does the vestibulospinal tract reach the cerebellum?

Answer 34

Caudal

Question 35

What clinical signs might you see in a central vestibular disorder that you wouldn't see in a peripheral? (4)

Answer 35

- Altered mental state - cerebellar deficits - postural rection deficits - vertical nystagmus

Question 36

What is ataxia?

Answer 36

Any loss of control of voluntary muscles

Question 37

Within which bone is the middle ear found?

Answer 37

tympanic part of the temporal

Question 38

What membrane separates the external ear from middle ear?

Answer 38

tympanic membrane

Question 39

In non-mammals how many bones are contained in the middle ear and what are their names?

Answer 39

Just the stapes

Question 40

What are the functions of the muscles in the middle ear?

Answer 40

To reduce the noise that is heard if for example you are in a loud environment

Question 41

Which nerves cross the middle ear? (3)

Answer 41

- Facial - tympanic - post-ganglionic fibres from sympathetic fibres

Question 42

What structure connects the middle ear and nasopharnnx?

Answer 42

auditory tube

Question 43

What is the purpose of the auditory tube?

Answer 43

pressure equalisation, it closes when swallowing

Question 44

What are the three layers of the tympanic membrane?

Answer 44

- external epithelial lining - connective tissue with elastic and collagen fibres - inner mucous membrane

Question 45

What is another name for the auditory tube?

Answer 45

Estuchian tube

Question 46

Between which structures does the guttural pouch lie?

Answer 46

The estuchian tube and the pharynx

Question 47

Within which bone is the inner ear found?

Answer 47

Petrosal bone in the temporal bone

Question 48

What is the name of the cavity contained within the cochlea within the membranous labrynth? and what fluid runs through it?

Answer 48

Scala media, endolymph

Question 49

Where does the perilymph Flow in the cochlea? (4)

Answer 49

from the oval window, through the Scala vestibule, into the Scala tympani, to the round window

Question 50

Which species contain a round cochlea and why is this important?

Answer 50

mammals, It increases sensitivity as sound can't reverberate as much