balance

Question 1

vestibular system role

Answer 1

sensory apparatus of the inner ear that helps the body maintain polstural equilibirum as well as coordinating the position of the head and movement of the eys

Question 2

what are hair cells stimulatd by

Answer 2

movement of endolymph

Question 3

what is head positon sensed by

Answer 3

utricle and saccule

Question 4

what movement does the utricle sense

Answer 4

horizontal

Question 5

what movement does the saccule sense

Answer 5

vertical

Question 6

what does the saccule and utricle contain

Answer 6

sense organ called macule where stereocilia and their supporting cells are found

Question 7

what are stereocilia

Answer 7

actin based protrusions on audiotry and vestibular sensory cells that are required for hearing and balance

Question 8

what do stereo cilia convert

Answer 8

physical force from sound , head movement or gravity into an electrical signal, a process called mechanoelectrcial transduction

Question 9

how can the organs respond to changes in position and acceleration

Answer 9

because of the tips of their sterocilia project into a dense otolithic membrane made up of a mixture containing granules of calcium and protein called otoliths-ear stones

Question 10

action of moving and stones

Answer 10

when the head moves gravity causes the stones to move

Question 11

what does the movement of the stones case

Answer 11

the sterocilia to bend initiating action potenitals in the vestibular nerve fibres that innervate them

Question 12

what is head movement sensed by

Answer 12

semicircular canals

Question 13

what are semicircular canals

Answer 13

three ring like extensions from the vestibule

One ring is oriented in the horizontal plane and two others are in the vertical plane - degree of orientation is 90’

Question 14

what is at the base of each semicircular canal

Answer 14

enlarged region known as ampulla

Question 15

what does the ampulla contain

Answer 15

hair cell containing structure called the crista ampullaris

Question 16

what does the crista ampullaris respond to

Answer 16

rotational movement

Question 17

stereocilia and cupula

Answer 17

extend into cupula a membrane that attaches to the top of the ampulla

Question 18

role of vestibular system

Answer 18

works with visual system to keep objects in ofcus when the head is moving - vestibulo ocular reflex

Question 19

how do hair cells in vestibular apparatus detect movement

Answer 19

via endolymph

Question 20

vestibulo ocular reflex

Answer 20

7. Hair cells in the vestibular apparatus detect movement via endolymph
8. Action potential travels through to nerve fibres that synapse with the hair cells
9. These nerves converge to form the vestibular branch of the vesibulocochlear nerve (CN VIII)
   Signal travels to the brain and passes out in the cranial nerves of the relevant ocular muscles to trigger compensatory eye movement

Question 21

what is th result of the vestibulo occular reflex

Answer 21

physiological form of nystagmus - involuntaye ey movement

Question 22

what can imbalance in the VOR lead to

Answer 22

pathological nystagmus

Question 23

role of vestibulospinal tract

Answer 23

motor output to neck back and leg muscles

Question 24

role of medial longitudinal fasciculus

Answer 24

motor output to eyes

Question 25

organ of hearing

Answer 25

cochlea

Question 26

action of cochlea

Answer 26

turns mechanical energy of sound waves into electrical signals