Spinal Cord-- Ascending Systems

Question 1

Function(s) of the Dorsal Column Pathway (DCP)

Answer 1

(1) 2 point discrimination
(2) Vibration sense
(3) Proprioception

Question 2

What is Proprioception?

Answer 2

The ability to consciously sense positioning of a limb even with no visual stimulation. It is due to the perception of muscle spindle and Golgi tendon receptors.

Question 3

What type of fibers make up the dorsal column pathway?

Answer 3

GSA

Question 4

Important receptor types affiliated with the DCP

Answer 4

(1) Meissner’s Corpuscle
(2) Pacinian Corpuscle
(3) Ruffini Ending
(4) Joint Receptor
(5) Neuromuscular Spindle
(6) Golgi Tendon Organs

Question 5

Information below T6 is found

Answer 5

Medially in what is called the fasciulus gracillis

Question 6

Information above T6, including the head, is found

Answer 6

Laterally in the fasciculus cuneatus

Question 7

Medial lamiscus

Answer 7

Where second order fibers pile up after exiting the gracile and cuneate nuclei

Question 8

How does the nervous signal end up at the opposite end from which it began?

Answer 8

Crosses the medulla at the internal arcuate fibers

Question 9

Area 312 (broddman’s area)

Answer 9

Somatosensory cortex. It handles afferent information

Question 10

What area is in front of the central sulcus?

Answer 10

Area 4, which controls motor functions. It has efferent information.

Question 11

What part of the body has its sensory towards the midline of the parietal cortex? Towards the lateral end?

Answer 11

From midline to lateral end:

Feet, hands, some head (minimal as CNV mainly handles this), large area for lips.

Question 12

General path for dorsal column pathway

Answer 12

(1) Enters dorsal root
(2) 1st synapse- nucleus cuneatus/gracilis
(3) 2nd synapse- VPL (after traveling via medial lamiscus)
(4) 312 area

Question 13

Dorsal spinocerebellar and ventral spinocerebellar tracts register…

Answer 13

Unconscious sensory

Question 14

Rombwerg Sign

Answer 14

Loss of Tabes dorsalis

Issues with dorsal column pathway

Positive if person requires vision in order to stand steadily. Said to be positive for patients with dorsal column injury. Negative for cerebellar ataxia.

Question 15

VPL

Answer 15

Ventral Posterolateral Nucleus

Receives information from the neospinothalamic trat and the medial lemniscus of the dorsal column and projects them to Brodmann’s area 312