Lecture 46 - somatosensory 2

Question 1

define proprioception

Answer 1

CNS is unconsciously aware of body part position in space using information regarding muscle length/tension

Question 2

what components are involved in giving information to the CNS

Answer 2

vestibular apparatus in inner ear
stretch receptors in muscle spindles and golgi tendon organs

Question 3

what 2 proprioceptive components are found in joints

Answer 3

ruffini’s endings
pacinian corpuscles

Question 4

what 2 proprioceptive components are found in muscles

Answer 4

golgi tendon organs
muscle spindle

Question 5

what do the afferent dendrites of muscle spindles wrap around

Answer 5

non-contractile center of intrafusal muscle fibers

Question 6

how are intrafusal muscles organized

Answer 6

parallel and alternating with extrafusal muscle fibers

Question 7

function of alpha-motor neurons

Answer 7

innervate extrafusal muscles
message from CNS to contract

Question 8

function of gamme-motor fibers

Answer 8

innervate intrafusal muscles
keeps contractile state synched

Question 9

summarize a stretch reflex

Answer 9

1. stretch in extra- and intra-fusal muscle
2. opens mechanically gate Na+ channels
3. action potential
4. information to CNS

Question 10

T/F: collagen fibers are intertwined with golgi tendon dendrites

Answer 10

TRUE

Question 11

when golgi tendon dendrites are ____, collage fibers become ____ during _____

Answer 11

depolarized; compact; contraction

Question 12

what is the conscious proprioceptive tract for forelimbs

Answer 12

fasciculus cuneatus (spinal cord)
nucleus cuneatus (myelencephalon)
cross conlateral
medial lemniscus (brainstem)
cortex (telencephalon)

Question 13

what is the conscious proprioceptive tract for hindlimbs

Answer 13

spinomedullary tract (spinal cord)
nucleus thoracicus (spinal cord)
join fasciculus cuneatus
medial lemniscus (brainstem)
thalamus
somatosensory cortex

Question 14

what is the major difference between conscious and unconscious proprioceptive tract

Answer 14

unconscious is ipsilateral, straight to cerebellum, and tracts through spinal cord

Question 15

summarize A-delta fibers

Answer 15

FAST myelinated
transmit extreme, sharp, localized signals

Question 16

summarize C fibers

Answer 16

SLOW unmyelinated
multiple noxious stimuli (deep, throbbing)

Question 17

what do peptidergic fibers secrete

Answer 17

P substance (small peptide)

Question 18

what do nonpeptidergic secrete

Answer 18

glutamate and other transmitters

Question 19

T/F: pain transmission takes the spinocervicothalamic and spinothalamic tracts

Answer 19

TRUE

Question 20

T/F: pain transmission of the forelimb stays ipsilateral

Answer 20

FALSE - crosses contralaterally

Question 21

subpopulation of spinal interneurons produce

Answer 21

opiate neurotransmitters, enkephalins, endorphins, and dynorphins

Question 22

where are opiate receptors

Answer 22

presynaptic terminals of primary afferents

cell bodies of spinothalamic neurons

Question 23

where is periaqueductal gray and what does it do?

Answer 23

gray matter in the midbrain; primary activators of opiate interneurons

Question 24

neuropathic pain

Answer 24

abnormal sensation of pain produced by non-painful stimuli

Question 25

aspirin, acetaminophen, and NSAIDs pain modulation

Answer 25

modulate prostaglandins (vasodilators), anti-inflammatory function

Question 26

opioid pain modulation

Answer 26

binds to opiate receptors in the CNS ; very potent