b) only k+ channels are still open, so na+ entry is offset by k+ loss.
c) only a few k+ channels have returned to their resting position.
d) the statement is incorrect; a threshold-level depolarization always triggers an action
potential.
e) some na+ channels have returned to their resting position and k+ channels are still
open, so na+ entry is offset by k+ loss.
12) match the change with the cardiovascular event described.
a. increased
b. decreased
c. unchanged
d. stopped
blood pressure decreases during sleep. how does this affect velocity?
13) the most complex endocrine responses involve the
a) thyroid gland.
b) pancreas.
c) adrenal glands.
d) hypothalamus.
e) thymus.
14) during mild to moderate exercise, arterial ph, po2, and pco2 are
a) nearly normal.
b) nearly half of normal.
c) almost twice as high as normal.
15) it is the middle of winter and you walk over an icy patch and lose your balance. as
you begin to fall, you react by extending your arms to catch yourself. in this instance,
what type of reflex is occurring?
a) stretch reflex
b) tendon reflex
c) flexor reflex
d) crossed extensor reflex