HES 202- Week 3 Golgi Tendon Organs and Joints & Vestibular System Pt. 1

Question 1

Where are GTO’s located

Answer 1

In the tendon junction

Question 2

GTO spindles are spread throughout the muscle belly and how do they lie

Answer 2

parallel

Question 3

GTO’s lie in a… with muscle fibres

Answer 3

series

Question 4

What type of afferent fibers innervate the GTO’s

Answer 4

1b afferent

Question 5

GTO’s are bundles within a capsule and include what 2 things

Answer 5

1) nerve endings
2) collagen fibers

Question 6

Nerve endings are____ among collagen fibers

Answer 6

interdigitate (which means interlocked)

Question 7

What are the two roles of muscle spindle receptors

Answer 7

1) Sense muscle length
2) Sense muscle velocity

Question 8

What are the 2 functions of the GTO receptors

Answer 8

1) muscle receptors that provide feedback to the CNS about muscle force/tension
2) primarily active muscle force/tension

Question 9

The level of force neccessary to excite a GTO depends on…

Answer 9

mode of activation

Question 10

How many newtons does a passive stretch require

Answer 10

2 newtons

Question 11

how many millinewtons can an active contraction activate?

Answer 11

30-90 millinewtons

Question 12

Are GTO’s much more sensitive to passive oractive generated forces

Answer 12

much more sensitive to actively generated forces

Question 13

Are GTO’s sensitive to muscle contraction and what do they respond to

Answer 13

yes. They respond to increased muscle tension during a twitch

Question 14

What is the function of the GTO?

Answer 14

Inhibit the agonist muscle. 2 Main functions: protective mechanism and modulate force

Question 15

How doe GTO’s provide motor feedback?

Answer 15

feedback to spinal cord via 1b afferent

Question 16

What is the autogenic inhibation

Answer 16

reflex that inhibits agonist motor neurons. It decreases Force Output

Question 17

What are GTO’s sensitive to?

Answer 17

sensitive to muscle tension.

Question 18

When are GTO’s activated

Answer 18

activated when muscle tension increases

Question 19

Where are joint receptors located and where are they not found

Answer 19

Located within joint capsule, joint ligaments, and loose articular tissue. No receptors in cartilaginous surfaces of the joint or in synovial membranes.

Question 20

What are the three main roles of joint receptors?

Answer 20

1) respond primarily at the limits of joint movement (extremes)

2) respond to joint pressure (joint swelling)

3) Joint receptors code ambiguously for joint movements (respond to both flexion and extension)

Question 21

What do joint recptors cause on alpha motor neurons

Answer 21

cause weak and infrequent effects on alpha motor neurons

Question 21

What neurons does the relfex activity happen on for joint receptors

Answer 21

reflex activity on alpha motor neurons

Question 22

What needs to happen to the knee ligament before EMG activity can be detected

Answer 22

knee ligaments must be heavily stretched before an detection from EMG

Question 23

What do the semicircular canals care about and what are the three parts to them

Answer 23

They deal with head rotation and there is the anterior, posterior, and horizontal

Question 24

What do the Otolith organs care about and what are the two parts

Answer 24

care about linear motion and 2 parts are utricle and saccule

Question 25

What is the function of hair cells (mechanoreceptors)

Answer 25

transform mechanical energy into neural activity

Question 26

What are the 2 parts of the hair cell

Answer 26

Kinocillium (apex of the hair cell) Stereocillium (linked stair-like structure)

Question 27

What happens when stereocillia are pushed towards the kinocillium

Answer 27

hair cells depolarize

Question 28

What happens when stereocillia are pushed away from the kinocillium

Answer 28

hair cells depolarize

Question 29

what do mechanorecpetors (stereocilia and kinocilium respond to

Answer 29

respond to acceleration of gravity that is in line with hair cells

Question 30

What does the semi-circular canal detect

Answer 30

angular acceleration

Question 31

What is the canal filled with

Answer 31

filled with fluid (endolymph(

Question 32

What is the cupula

Answer 32

house hair cells in the crista

Question 33

What does acceleration lead to?

Answer 33

leads to increased firing rates, while deceleration leads to hyperpolarization (decreased firing) in the 8th nerve afferent

Question 34

What happens during periods of constant velocity

Answer 34

the hair cells return to normal leakiness and the 8th nerve afferent return to baseline firing rates

Question 35

What are the three angular accelometers in the semicircular canal

Answer 35

anterior SCC, Posterior SCC, and horizontal SCC

Question 36

What does balance between left and right excitation and inhibation

Answer 36

leads to sensation of head rotation

Question 37

What does head rotation causes in terms of endolymph

Answer 37

causes opposite endolymph fluid movement

Question 38

What does the opposite endolymph fluid movement cause

Answer 38

causes stereocilia to be pushed towards kinocilium in the left semicircular canal = excitation and the opposite response in the right semicircular canal = inhibition

Question 39

What are the semi-circular canals

Answer 39

Capula surrounded by endolymph (fluid)

Question 40

What is the otlithic membrane

Answer 40

gel-like substance

Question 41

What does the otoliths organs detect

Answer 41

detects linear acceleration

Question 42

What do the utricle detect

Answer 42

horizontal linear acceleration

Question 43

What does Saccule detect

Answer 43

vertical linear acceleration

Question 44

What causes the cilia to move

Answer 44

the shearing of the membrane

Question 45

What happens when the head tilts or accelerates

Answer 45

gravity causes the otoliths to slide, pulling the stereocillia and causing the hair cell to depolarize

Question 46

What are otoliths sensitive to

Answer 46

sensitive to linear acceleration