Ch 10. Spinal Cord

Question 1

Is the PNS considered a part of CNS?

Answer 1

Yes, spinal cord is a uniformly organized part of the CNS

Question 2

Which one is more difficult than other, spinal cord or brain?

Answer 2

spinal cord is one of the simplest in a relative sense

Question 3

Do principles of cord function apply to other levels of the nervous system too?

Answer 3

Yes, many principles of cord function also apply to other levels of the nervous system

Question 4

How much of motor neurons reside in the spinal cord?

Answer 4

All the motor neurons supplying the muscles we use to move our bodies around reside in the spinal cord.

Question 5

How much of autonomic efferents reside in the spinal cord?

Answer 5

Major populations of autonomic efferents.

Question 6

How much of the sensory input the spinal cord receives either from the body or the head? and what does it do on them?

Answer 6

All the sensory input from the body, and some from the head. It performs the initial processing operations on most of this input.

Question 7

What is the measurements of the spinal cord? and how much does it weigh?

Answer 7

42 to 45 cm long and about 1 cm in diameter at its widest point, and it weighs only about 35 g .

Question 8

How does spinal cord look like in terms of nerve roots attached to it? (not obviously)

Answer 8

It’s anatomically segmented.

Question 9

What kinds of rootlets enter or leave the cord?

Answer 9

A continuous series of dorsal (i.e., posterior) rootlets enter the cord in a shallow longitudinal groove (the posterolateral sulcus) on its posterolateral surface, and a continuous series of ventral (i.e., anterior) rootlets leaves from the poorly defined anterolateral sulcus

Question 10

What do ventral and dorsal rootlets do? and what does that have to do with spinal nerves?

Answer 10

dorsal and ventral rootlets from discrete sections of the cord coalesce to form dorsal and ventral roots, which in turn join to form spinal nerves.