Question

question 64
0.25 pts
one of the components of the blood-brain barrier is:
astrocytes
neurons
myelin
oligodendrocytes
question 65
0.25 pts
which is not true of the myelin sheath?
it is associated with white fibers in the brain.
it is important for nerve impulse conduction.
it covers cell bodies in the brain and spinal cord.
it is destroyed in those with multiple sclerosis.
question 66
0.25 pts
along a neuron, the correct pathway for impulse conduction is:
dendrite, axon, cell body, and receptor.
dendrite, cell body, and axon.
axon, cell body, and dendrite.
receptor, axon, and cell body.

Explanation:

Question 64

The blood - brain barrier has astrocytes (a type of glial cell) as one of its components. Neurons are the functional units of the nervous system, myelin is a fatty substance that insulates axons, and oligodendrocytes are responsible for myelinating axons in the central nervous system, but they are not a component of the blood - brain barrier.

The myelin sheath is associated with white fibers (myelinated axons) in the brain, is important for nerve impulse conduction (speeds up the conduction), and is destroyed in multiple sclerosis. However, the myelin sheath covers axons, not cell bodies in the brain and spinal cord.

The correct pathway for impulse conduction along a neuron is from dendrite (which receives the signal), to cell body (where the signal is integrated), and then to axon (which transmits the signal away from the cell body).

Answer:

A. astrocytes

Question 65