Question

43 multiple choice 1 point in viewing the spinal cord cross section, the central canal contains plasma. white matter areas contain fiber tracts that carry ascending and descending messages. the gray matter is shaped like a caterpillar. spinal nerves carry both sensory and association neurons.

Explanation:

• Analyze each option:
• The central canal contains cerebrospinal fluid, not plasma, so the first option is incorrect.
• White matter in the spinal cord consists of myelinated fiber tracts (axons) that carry ascending (sensory) and descending (motor) neural messages, so this option is correct.
• Gray matter in the spinal cord is shaped like a butterfly, not a caterpillar, so the third option is incorrect.
• Spinal nerves carry sensory (afferent) and motor (efferent) neurons, not association neurons (which are mostly in the brain), so the fourth option is incorrect.

Answer:

B. white matter areas contain fiber tracts that carry ascending and descending messages.