13 vestibular system

Question 1

vestibular system

Answer 1

• provides you with orientation
• sense of balance and information about the body’s position
• located in the inner ear

Question 2

vestibular apparatus

Answer 2

• connected series of endolymph-filled, membranous tubes
• has 3 membranous semicircular canals, utricle and saccule

Question 3

semicircular canals

Answer 3

• detect angular accelaration during rotation of the head along 3 perpendicular axes :
• horizontal axis
• vertical axis
• anterior-posterior axis

Question 4

hair cells

Answer 4

• sensory receptors (mechanoreceptors)
• have stereocilia protruding from one end
• located in the semicicular canals, utricle and saccule

Question 5

cupulla

Answer 5

encapsulates the stereocilia

-when the head moves the endolymph fluid lags behind, and thus pushes on the cupula which then moves the hair cells. If you keep moving the fluid catches up and the hair return to being straight

Question 6

ampulla

Answer 6

swelling in the canals

Question 7

bending of the hair cells

Answer 7

direction of rotational head movements determine the direction in which the stereocilia are bent and which cells are stimulated

Question 8

otolith organs

Answer 8

-provide information about linear acceleration of the head and about changes in head position r_elative to the force of gravity_

2 types :

utrile : respond to linear acceleration (u tricky line)

sacule : respond to vertical acceleration (sacule vert)

Question 9

vestibular information used in 3 pathways

Answer 9

1. control of eye muscles
2. reflex mechanisms for upright posture and balance
3. provides conscious awareness of the body’s position

Question 10

control of eye muscles

Answer 10

-even if we move our head our eyes remain fixed on the same point

Question 11

nystagmus

Answer 11

large back and forth movement of the eyes

• occurs in healthy people
• spinning in chair

Question 12

reflex mechanism for upright posture and balance

Answer 12

supports the head during movement, orientation of the head in space, and reflexes accompanying locomotion

-provides conscious awareness of the position and acceleration of the body, perception of the space surrounding the body, and memory of spatial information

Question 13

motion sickness

Answer 13

rooted in the mismatch between sensory system relating visual and balance information