Dr. Najeeb- Ascending Tracts 2

Question 1

What structures are included as part of the Dorsal Column Medial Lemniscus system?

Answer 1

• the system of fusciculus Gracilis and Cuneatus
• Nucleus Gracilis and Cuneatus
• Arcuate fibers (crossing)
• Medial Lemnisci (Fibers going up)

Question 2

What kind of information goes through the Dorsal Column Medial Lemniscus system? (Sensory/motor ; modern/primitive?)

Answer 2

Sensory, modern

Question 3

Does the dorsal column system fibers cross the midline?

Answer 3

No.

Decussation occurs via the internal arcuate fibers, at the level of lower medulla (axons of 2nd-order neurons)

Question 4

What is the name of the fibers which cross the midline?

Part of the Dorsal Column Medial Lemniscus System

Answer 4

Internal Arcuate fibers

Question 5

What is the name of the ascending fiber bundles ?

Axons of 2nd-order neurons

Answer 5

( L. & R.)Medial Lemniscus

Or Medial Lemniscus system

Question 6

Where does the R. Medial Lemniscus gets his information from?

Answer 6

Axons of L. Gracilis & L. Cuneatus nuclei (after crossing the midline as the Arcuate fibers)

Question 7

Where does the L. Medial Lemniscus gets his information from?

Answer 7

Axons of R. Gracilis & R. Cuneatus nuclei (after crossing the midline as the Arcuate fibers)

Question 8

Where can we find 2nd-order neurons?

Answer 8

Gracilis & Cuneatus nuclei (lower medulla)