chapter 3.4 // spinal cord

Question 1

gray matter

Answer 1

composed largely of cell bodies and unmyelinated interneurons

Question 2

dorsal horns (gray matter)

Answer 2

two dorsal arms of the spinal gray matter

Question 3

ventral horns (gray matter)

Answer 3

two central arms

Question 4

white matter

Answer 4

composed largely of myelinated axons

Question 5

31 pairs of spinal nerves

Answer 5

attached to the spinal cord at different levels. Each of these 62 nerves divides as it nears the cord and its axons are joined to the cord via one of two roots: the dorsal root or the ventral root.

Question 6

All dorsal root axons (somatic or autonomic

Answer 6

are sensory/afferent unipolar neurons with their cell bodies grouped together just outside the cord to form the dorsal root ganglia. Many synaptic terminals are in the dorsal horns.

Question 7

Neurons in the ventral root

Answer 7

are motor/efferent multipolar neurons with their cell bodies in the ventral horns.

• those in somatic system project to skeletal muscles
• those in autonomic system project to ganglia where they synapse on neurons that in turn project to internal organs.