When an action potential is over and the membrane has returned to resting potential, the voltage-gated sodium channel:
a. is closed and not capable of opening
b. is closed and capable of opening
c. is open
d. open and not capable of closing
e. two of these answers.
B
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The innermost layer of the heart is called the:
a. epicardium b. endocardium c. visceral pericardium d. both A and C above
You have been diagnosed with glaucoma. The doctor is worried that the pressure within the anterior cavity will damage the corneal cells, even with treatment. How is this explained?
A) The cornea is the location of the photoreceptor cells. B) The damaged lens will stick to the cornea, affecting light refraction. C) The glaucoma will cause the pupils to get smaller, allowing less light through the cornea. D) The cornea cannot easily get nutrients and oxygen. E) The cornea will be pushed inward toward the back of the eyeball, causing pressure increases on the retina.
Match the following systems to their functions:
A) Lymphatic B) Cardiovascular C) Immune D) Endocrine 1) Controls the body with chemical molecules called hormones. 2) Delivers oxygen and nutrients to the tissues. 3) Produces antibodies that neutralize foreign substances. 4) Removes and filters excess fluid from tissues.
Identify the structure labeled "9."
