Vestibular System

Question 1

Functions of the Vestibular System

Answer 1

1. Maintain upright posture

2. coordinate head movement with eye movement

Question 2

Parts of the Inner Ear

Answer 2

cochlea (hearing), utricle and saccule (linear acceleration/gravity), 3 semicircular canals (rotary acceleration)

Question 3

Hair Cells

Answer 3

movement of cilia converted into action potentials. Tonically active: bend one way increases activity, bend the other way decreases activity

Question 4

Semicircular Canals

Answer 4

superior semicircular canal, lateral semicircular canal, and posterior semicircular canal. They are oriented in different planes- one vertical, one horizontal, and one back and forth

Question 5

Utricle and Saccule

Answer 5

detect tilt, gravity. And detect linear acceleration

Question 6

Head Tilt

Answer 6

towards the lesion of a peripheral vestibular lesion

Question 7

Rotation Induced Eye Movements

Answer 7

eyes move in an equal and opposite direction (slow phase). Forebrain induces corrective movement toward direction (fast phase)

Question 8

Lesion Eye Movements

Answer 8

eyes move toward lesion (slow phase). Corrective phase away from lesion (fast phase)

Question 9

Spontaneous Nystagmus

Answer 9

horizontal nystagmus, fast phase to the right. Left peripheral vestibular lesion

Question 10

Pendular Nystagmus

Answer 10

equal speed in each direction. Congenital abnormality in the visual pathways. Not a vestibular lesion

Question 11

Cerebellar Lesion Head Tilt

Answer 11

head tilts away from lesion

Question 12

What can vestibular lesions cause?

Answer 12

head tilt, leaning and falling (vestibular ataxia), abnormal eye movements