Deep Sensibility

Question 1

Functions DCML and spinocerebellar tracts

Answer 1

• vibration
• discriminatory touch (fine touch)
• pressure
• proprioception (position sense & kinesthesia)

Question 2

Define discriminatory touch

Answer 2

Distance at which 2 stimuli are perceived separately, necessary for stereognosis and grapaesthesia

Question 3

Deep sensibility ascends through the spinal cord via the…

Answer 3

DCML and spinocerebellar tracts

Question 4

What is the specific area of skin that a spinal nerve innervates?

Answer 4

Dermatome

Question 5

Cutaneous & subcutaneous mechanoreceptors (named receptors) have ____ fibers

Answer 5

A-beta or A-alpha

Question 6

Nociceptors & thermal receptors have _____ fibers

Answer 6

A-delta or C

Question 7

When do fast adapting somatic cutaneous sensory receptors fire?

Answer 7

Beginning and end of stimulus/signal

Question 8

When do slow adapting somatic cutaneous sensory receptors fire?

Answer 8

Whole duration of stimulus/signal

Question 9

A-delta fiber myelination

Answer 9

Least myelin

Question 10

C fiber myelination

Answer 10

No myelin

Question 11

A-alpha myelination

Answer 11

Most myelination

Question 12

A-beta myelination

Answer 12

Second most

Question 13

A-delta sensory receptors function

Answer 13

Pain & temperature

Question 14

C fibers sensory receptors function

Answer 14

Temperature, pain, itch

Question 15

Central axons of dorsal root ganglion in fasciculus gracilis ascend and synapse with ____ in the ____

Answer 15

Nucleus gracilis in medulla

Question 16

How do Fibers of dorsal columns ascend?

Answer 16

Somatotopically
Most medial fibers = sacral

Question 17

Central axons of dorsal root ganglion carrying conscious proprioception in fasciculus cuneatus synapse with ____ in the ____

Answer 17

Nucleus cuneatus in medulla

Question 18

Some fibers of fasciculus cuneatus enter the cerebellum as the ____, and relay…

Answer 18

Cuneocerebellar tract
Unconscious proprioception from T6 up

Question 19

As fibers of FC and FG enter the spinal cord, they send collaterals to…

Answer 19

Various levels of dorsal & ventral horn bilaterally for reflexes

Question 20

Collateral fibers of FC and FG travel in the ____

Answer 20

Fasciculus proprius

Question 21

Central axons of DRG which detect proprioception (conscious & unconscious) from lower limb enter the dorsal horn and synapse with ____

Answer 21

Nucleus dorsalis (Clarke’s column)

Question 22

Nucleus dorsalis gives rise to the ____

Answer 22

Dorsal spinocerebellar tract

Question 23

At the medulla, some dorsal spinocerebellar fibers of DSCT (conscious proprioception) synapse with ____

Answer 23

Nucleus Z

Question 24

Some dorsal spinocerebellar fibers of DSCT (unconscious proprioception) enter the…

Answer 24

Cerebellum - inferior cerebellar peduncle

Question 25

Central axons of DRG which detect unconscious proprioception from lower extremities enter the ____ and synapse with ____

Answer 25

Dorsal horn
Nucleus proprius
(Becomes VSCT)

Question 26

Nucleus proprius gives rise to the ____

Answer 26

Contralateral ventral spinocerebellar tract

Question 27

Fibers of nucleus proprius ascend to the ____, and enter the cerebellum via ____

Answer 27

Midbrain
Superior cerebellar peduncles (after crossing 2nd time)

Question 28

NG, NC and nucleus Z extend ____ that cross the ____ to form the ____

Answer 28

Internal Arcuate fibers
Great sensory decussation
Medial lemniscus

Question 29

Somatotopic organization of medial lemniscus in medulla

Answer 29

Cervical, thoracic, lumbar, sacral
= dorsal to ventral

Question 30

Somatotopic organization of medial lemniscus in pons & midbrain

Answer 30

Cervical, thoracic, lumbar, sacral
= medial to lateral

Question 31

Medial lemniscus ends in the ____

Answer 31

Thalamus
(Fibers will end in sensory cortex)

Question 32

Describe variations in receptive field size of mechanoreceptors

Answer 32

Small: each receptor is responsible for a small area of skin; more receptors in an area
Large: receptors are responsible for larger areas; less receptors in a given area