Week 12: Vestibular System and Balance

Question 1

Vestibular labyrinth

Answer 1

Connected to the cochlea The vestibular labyrinth houses multiple sensory organs for the detection of rotational and linear acceleration including gravity. The three semicircular canals in association with their ampullae, which house the sensory hair cells

Question 1

Semicircular canals

Answer 1

The semicircular canals are three tiny, fluid-filled tubes in the inner ear that help you keep your balance. When your head moves around, the liquid inside the semicircular canals sloshes around and moves the tiny hairs that line each canal.

Question 2

Ampulla

Answer 2

The ampulla is a localized dilatation at one end of the semicircular duct. A patch of innervated hair cells is found at the base of the ampulla in a structure termed a crista (meaning crest). Cupula is in the ampulla. When there is movement, the liquid pushes the cupula which moves the hairs and the hair cells one way inhibits the action potential faster.

Question 3

Cypula

Answer 3

A cupula is a small, inverted cup or dome-shaped cap over a structure, including: Ampullary cupula, a structure in the vestibular system, providing the sense of spatial orientation. Cochlear cupula, a structure in the cochlea. Cupula of the pleura, related to the lungs.

Question 4

Hair cells

Answer 4

Gravity puts force on otoliths which presses down and bends the macula an the macula bends the hairs and tells the hair cells to send an action potential down the vestibular nerve.

Question 5

Utricle

Answer 5

Horizontal organ (would respond if you’re going straight up and down but your head isn’t moving; jumping on a trampoline, bending over to pick something off the ground and your head goes down by your feet)

Question 6

Saccule

Answer 6

Vertica (would sense if you’re accelerating or decelerating in the car but your body isn’t physically moving)

Question 7

Otoliths

Answer 7

Carbody crystals “ear rocks”

Question 8

Vestibulocerebellum

Answer 8

Are of the cerebellum that receives vestibular system in both ears
- Using the information postural and eye movements in response to movement
- E.g., walking towards a door to open it; your eyes fixate on the handle to pull open the door even as you get closer thanks to the information of the vestibulocerebellum

Question 9

Vertigo

Answer 9

Illusion of motion
Physical vertigo: after spinning, the endolymph is still moving even though you are not
Pathologic vertigo: Due to imbalance of vestibular signals secondary to a lesion of the vestibular system, vestibular nerve, or area in the brain where vestibular information is processes
- Results in nystagmus, unsteadiness, ataxia, nausea, and vomiting

Question 10

Reasons people have poor balance

Answer 10

• Issues in the vestibular system
• Double vision (Diplopia)
• Not receiving sensory information (e.g., neuropathy)
• Poor coordination (due to impairment in brainstem/cerebellum)
• Orthostatic hypotension (not enough blood in the brain when changing positions)

Question 11

Function in sitting test

Answer 11

The FIST is a clinical examination of sitting balance, designed to be conducted at the patient’s bedside

Question 12

Timed up and go

Answer 12

Directions: Patients wear their regular footwear and
can use a walking aid, if needed. Begin by having the
patient sit back in a standard arm chair and identify a
line 3 meters, or 10 feet away, on the floor.