Central nervous system axons regenerate much better in fish than in mammals because
fish:
a. nerves do not have to travel so far to reach their target.
b. myelin does not secrete proteins that inhibit axon growth.
c. nerves have so much more myelin than do mammal nerves.
d. myelin secretes a protein that accelerates regeneration.
Stress activates two systems. One is the:
a. HPA axis, which reacts more quickly than the other.
b. HPA axis, which becomes increasingly important with prolonged stressors.
c. autonomic nervous system which secretes the hormone ACTH.
d. autonomic nervous system which secretes the hormone cortisol.
During the entire course of events from the start of an action potential until the
membrane returns to its resting potential, what is the net movement of ions?
a. sodium in, potassium in