somatosensory I

Question 1

afferent muscle spindle fibers are?

fiber types?

Answer 1

• annulospiral (Ia)

- flower spray (II)

Question 2

golgi tendon organ:
senses what?
fiber type?

Answer 2

• muscle force, tension

- Ib

Question 3

THREE types of fibers in the skin?

Answer 3

• A beta
• A delta
• C

Question 4

ruffini corpuscle function

Answer 4

joint movement and pressure

Question 5

what are the FOUR sensory fiber types

Answer 5

A alpha; A beta; A delta; C

Question 6

what are the FOUR motor fiber types

Answer 6

A alpha; A gamma; B; C

Question 7

sensory A alpha receptors go to___ in spinal cord

Answer 7

DCML

Question 8

sensory A beta receptors go to___ in spinal cord

Answer 8

DCML

Question 9

rank the conduction velocity of the different sensory classes

Answer 9

A alpha > A beta > A delta > C

remember that the FATTER the nerve the FASTER it goes

Question 10

rank the conduction velocity of the different sensory classes

Answer 10

A alpha > A gamma > B > C

Question 11

which fibers enter the dorsal horn most laterally

Answer 11

C fiber. the A delta fiber is more medial in the dorsal horn

Question 12

deformation of encapsulated nerve ending alters?

Answer 12

permeability of ion channels generating a receptor potential

Question 13

stereognosis=

tracts?

Answer 13

recognition of a 3-D shape, (size, texture);
fasciculus gracilis (below t6) and cuneatus

Question 14

somatosensory tracts

Answer 14

posterior column-medial lemniscus
trigeminothalamic
spinoCbellar
ALS

Question 15

conductance speed of PCML

Answer 15

fast conducting

Question 16

relays of PCML

Answer 16

limited convergence (doesn’t dilute the sensations much), limited number of synaptic relays

Question 17

functional component of PCML

Answer 17

GSA

Question 18

graphesthesia test

Answer 18

trace a number or letter on someones hand and see if they recognize what you wrote

Question 19

ascending spinal border cells can send info to

Answer 19

cBellum

Question 20

post synaptic posterior column pathway

Answer 20

nondiscriminative tactil input
redundant dorsal column system
travels distally with PCML

Question 21

lateral inhibition definition

Answer 21

blocks out noisy peripheral input so that only the strongest excitatory input is receieved

Question 22

brodman area 3a gets info from

3b?

Answer 22

muscle spindles

pain thermal touch

Question 23

describe the relationship between RECEPTIVE fields and HOMONCULUS

Answer 23

SMALL receptive fields are PRECISE so they have a large representation in the homonculus
(lips, fingers, etc.)

Question 24

cuneocerebellar tract runs

Answer 24

in dorsal column, but it synapses in its own nucleus… not gracile ( upper limb equivalent of PCML)

Question 25

onuf’s nucleus

Answer 25

sends fibers for somatic innervation of urethral sphincter and anal sphincter S3-4

Question 26

spinal roots of achilles reflex

Answer 26

S1

Question 27

spinal roots of cremasteric reflex

Answer 27

L1-L2

Question 28

spinal roots of bulbocavernosus reflex

Answer 28

S2-4

Question 29

spinal roots of anal wink

Answer 29

S2-4….. this one is still gross.

Question 30

kinesthesia=

Answer 30

limb movment

Question 31

blood supply to trigeminal motor nucleus?

same blood supply as?

Answer 31

• SCA
• long circumferential branches of basilar
• • same as principal sensory nucleus

Question 32

trigeminoCBellar system:

___ connects through restiform body

Answer 32

-pars interpolaris (of spinal trigeminal nuc)

Question 33

lateral hemisphere of CBellum :
pathway?
fxn?

Answer 33

affects lateral corticospinal tract to help with motor planning for extremities

Question 34

intermediate hemisphere of CBellum :
pathway?
fxn?

Answer 34

lateral corticospinal tract and rubrospinal tract for distal limb coordination

Question 35

vermis and flocculonodular lobe of CBellum :
pathway?
fxn?

Answer 35

• proximal limb and trunk coordination of all the “ __spinal” paths
• balance and vestibulo-ocular reflexes (MLF)