313 FINAL 2

Question 1

GTOs are located at the

Answer 1

tendon junction

Question 2

what is the arrangement of spindles and GTOs?

Answer 2

Spindles lie in parallel to muscle fibers, GTOs in series.

Question 3

which afferent fiber innervates the GTO?

Answer 3

1B afferent.

Question 4

what do GTOs code for?

Answer 4

muscle force or tension.

Question 5

4 types of joint receptors and their classification

Answer 5

mechanoreceptors: ruffini receptors, pacinian receptors, fusiform corpuscle
nociceptors: small pain receptors

Question 6

what is the difference between mechanoreceptors and nociceptors?

Answer 6

the mechanoreceptors are larger, myelinated axons

Question 7

(joint) type 1 receptors

Answer 7

Ruffini receptors
low threshold, slowly adapting,
myelinated and then branch out, as it enters the tissue it loses the myelin and send out tendrils to embed themselves into the collagen
Located mainly in superficial layers of joint capsule
fires rapidly then less and regularly

Question 8

(joint) type 2 receptors

Answer 8

Pacinian corpuscles
low threshold, rapidly adapting
Located mainly in deep layers of joint capsule and articular fat pads.
actions potentials are generated at the beginning of the stretch, but it only fires at transition points (start/stop stretching)

Question 9

(joint) type 3 receptors

Answer 9

fusiform corpuscle
high threshold, slowly adapting
look just like GTO
if you strain the tissue enough and hold it strained, it will begin and maintain its action potential firing pattern

Question 10

Type III and IV receptors have strong projections on ___ _____ ____
Type I and II have weak and infrequent effects on the same ____ ____ ____

Answer 10

alpha motor neurons

Question 11

joint receptors generally do not have good control of the __ ___ ___

Answer 11

motor neuron pool

Question 12

gamma motor neurons are more influenced by ________ than _______

Answer 12

low threshold joint receptors than alpha MNs

Question 13

low threshold joint mechanoreceptors evoke (strong/weak) ___________ and _________ effects on ____ and ______ gamma MNs

Answer 13

strong excitatory and inhibitory effects on static and dynamic gamma MNs

Question 14

joint receptors have a strong connection onto ____ ____

Answer 14

gamma MNs

Question 15

both IPSP and EPSP are inferred from….

Answer 15

gamma MN pool

Question 16

joint receptors do not influence _____________ well

Answer 16

alpha MNs

Question 17

gamma motor neurons can…..

Answer 17

tune the muscle spindle system

Question 18

gamma dynamic makes the _____ more _____

Answer 18

the spindle more velocity sensitive

Question 19

gamma status makes the ____ more _____

Answer 19

the spindle more velocity sensitive

Question 20

Stimulation of ________ by joint receptors is sufficient to _______ the activity of the ______________.

Answer 20

Stimulation of gamma motoneurons by joint receptors is sufficient to modulate the activity of the muscle spindle afferents.

Question 21

Skin receptors and their adapting type

Answer 21

SA1 Merkel cells
FA1 Meissners corpuscles
SA2 Ruffini endings
FA2 Pacinian corpuscles

Question 22

Merkel cells

Answer 22

Irregular discharge when stimulated
Highly sensitive to edges and curvature
Moderately low threshold (30 nanometers)

slowly adapting type 1
Whatever you do to the cells makes them leak by bending them, which causes potentials on the axon
myelinated axon comes in and forms a synapse on the cell

Question 23

meissner corpuscles

Answer 23

Codes for velocity of skin indentation and motion across the skin
About 40% of innervation in the hand
Sensitive to low frequency vibration (most sensitive to 40-50 Hz)
Low threshold (6 nanometers)

fast adapting type 1
axon weaving through a lot of collaging

Question 24

ruffini endings

Answer 24

Regular discharge when stimulated
Very sensitive to lateral skin stretch
High threshold to indentation (300 nanometers)
Not in non human primates

slowly adapting type 1
activated by pulling the collagen
located in skin and not joints

Question 25

pacinian corpuscle

Answer 25

Codes for acceleration - change in indentation rate
Picks up high frequencies (300-400 Hz)
Extremely low threshold (0.08 nanometers)

fast adapting type 2
innervated by 1 axon, is located deep in the dermis

Question 26

process of mechanotransduction

Answer 26

nerve fibers come in and become unmyelinated. changes in ion channels on the axon bring in sodium, changing the membrane potential of the axon.

Question 27

mechanotransduction =

Answer 27

the process whereby mechanical energy (tissue deformation) gets converted into a voltage change in sensory afferent neurons

Question 28

cutaneous receptive field =

Answer 28

the region of the skin that is capable of driving a response in a particular neuron

Question 29

spatial code =

Answer 29

the size and shape of objects touching the hand can be coded for by SA1’s.

Question 30

what is detected by each type of skin receptor?

Answer 30

SA1: edges, curvature and texture
FA1: motion detection and grip control
SA2: skin stretch
FA2: feeling through objects, fine texture

Question 31

Both FAII and SAI units respond to……

Answer 31

transient ‘microslips’ between object and skin.

Question 32

what is coded for by the spindle, skin, GTO and joint receptors?

Answer 32

Skin receptors: indentations, movements, stretching of the skin
GTO: tension, force generated by a muscle around a joint
Muscle spindle: the length of muscles (contracting, lengthening) and the velocity of the change
Joint receptors: response to pressure, contractions around a joint, reflexes, gamma motor neuron interaction

Question 33

kinesthesis vs proprioception =

Answer 33

kinesthesis involves consciousness, whereas proprioception is more a reflexive issue (not necessarily conscious control).

Question 34

4 major contributors to kinesthesis:

Answer 34

1) sense of position and movement of the limbs, 2) sense of tension or force, 3) sense of effort or heaviness, and 4) sensations of body image and posure. Position sense vs movement sense.

Question 35

Evidence of a somatosensory role in proprioception and kinesthesis

Answer 35

disembodied lady, guillian barre syndrome, ian waterman, vit B toxicity in cats causing large fiber neuropathy

Question 36

which receptors code for lateral skin stretch and for which joint is moving?

Answer 36

SA2 and FA1

Question 37

H-reflex is used to…. (2 things)

Answer 37

test the strength of the monosynaptic reflex, and the level of excitability of a motor neuron pool in EMG

Question 38

H-reflex =

Answer 38

a reflectory reaction of muscles after electrical stimulation of sensory fibers in their innervating nerves

Question 39

orthodromic =

Answer 39

stimulating the axon and the action potential goes in the natural direction of travel into the spinal cord - correct direction of potential travel for afferent and efferent

Question 40

antidromic =

Answer 40

goes down the muscle spindle as the exact same size of the orthodromic - backwards propagation of the potential

Question 41

Peripherally stimulating a nerve causes…..

Answer 41

action potentials in 1a afferents and on the motorneurons

Question 42

stimulating the middle of an axon causes….

Answer 42

action potentials on 1a afferents that go in both directions, up and down (to where the spindle in the muscle is)

Question 43

latency =

Answer 43

time of stimulus to time of response

Question 44

H reflex changing size can indicate…

Answer 44

synapse strength change or motor neuron location change