W9 Vestibular system

Question 1

What does the Vestibular system contribute to?

Answer 1

Keepig our eyes still as we move.
Maintaining our upright posture.
Our ability to perceive our own movement within space.

Question 2

Semicircular canales

Answer 2

3 sets in each ear: horizontal, anterior, posterior

Question 3

Ampulla

Answer 3

Hair cells

Question 4

Otolith organs

Answer 4

Detect linear motions, tilting of the head

Question 5

Utricle and Saccule

Answer 5

Horizontal left to right and back to fowards.

Saccule (ventrical

Question 6

Vestibular labyrinth is filled with what?

Answer 6

Different chambers filled with endolymph and perilymph.

Question 7

Endolymph

Answer 7

high extra-cellular potassium concentration.

Question 8

What is the primary sensory receptors of the vestibular system

Answer 8

Hair cells: respond harder becuase they are all together, better at responding to low frequencies

Question 9

What do Vestibular hair cells have

Answer 9

hair bundle with stereocilia and tip links.
A kinocilium throughout life

Question 10

Vestibular hair cells are mechanosensitive.

Answer 10

Same principle as auditory system hair cells.
They respond to lower frequencies (0-20 Hz)
Resting potential, the channels are slightly at rest to enable them to get more negative: hyperpolarize them

Question 11

What are the two types of vestibular hair cells

Answer 11

Normal type of sensory sysnpas (Type 2)

Type 1: have this long cave, means lots of different synapses can communicate with the long dendrite, found in numerus points.

Question 12

What does the saccule and the utricle detect?

Answer 12

Head tilt and linear acceleration

Question 13

Location of hair cells

Answer 13

Sensory patch called macula.
The hair cells don’t have the same direction, they can be activated in diffreent direction.

Question 14

Gelatinous otolithic membrane:

Answer 14

inside theirs otoconia, respond to gravity because they are heavier.

Question 15

Why can Vestibular input to the CNS be ambiguous. ?

Answer 15

The membrane moves less quickly than the hair cells. They send exactly the same signals, they need other systems to understand the outputs.

Question 16

Cupula

Answer 16

Gelatinous structure penetrated by hair bundles.
Cupula is pushed around which moves the hair bundles which send potentials.
The inertia of endolymph during rotation displaces the cupula.

Question 17

Semicircular canals on either side of the head

Answer 17

Work in pairs.
Horizontal canals on both sides lie in roughly the same plane so can act as a functional pair.

The anterior canal on one side lies in parallel with the posterior canal on the other side so acts as a functional pair.

Question 18

Why do you feel dizzy when you’ve turned a lot

Answer 18

The endolymph moves the opposite direction than you and moves slower which is why you feel the dizziness after you’ve turned.

Question 19

Vestibulo-ocular reflex

Answer 19

When you shake your head you vestibular-ocular reflex is quicker.

Question 20

What does the vestibular nystagmus enable us to do?

Answer 20

It enables the resetting of eye position during sustained head rotation