Name: __________________________
Biology 449 - Animal Physiology
Fall 2007
Midterm 2 – MC Key
Fill in your scantron form as follows:
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Write and bubble in your name in the upper left (last name first).
Follow any additional instructions provided in class.
Sign your form on the upper right. By so doing you verify that you are abiding
by Creighton’s policy on academic honesty.
Multiple choice: As always, choose the best answer for each multiple-choice question.
Answer on your scantron form. Each question is worth 3 points.
1. By definition, a tropic hormone is one that
a.
b.
c.
d.
e.
promotes growth.
promotes the release of another hormone.
is released from a modified neuron.
is a modified form of cholesterol.
is not carried in the blood.
2. Which of the following secretes only amine hormones?
a.
b.
c.
d.
e.
Adrenal cortex
Adrenal medulla
Anterior pituitary
Gonads
Hypothalamus
3. Most hormones bring about a response in target cells through which of the following
mechanisms?
a. The hormone binds to and opens or closes channel proteins in the cell membrane.
b. The hormone binds to and activates G-protein complexes that open or close channel
proteins in the cell membrane.
c. The hormone binds to and activates G-protein complexes that activate secondary
messengers or enzymes that cause changes in cellular activity.
d. The hormone passes through the membrane and directly activates secondary
messengers or enzymes.
e. The hormone passes through the membrane and changes RNA transcription rates.
4. Gonadotropin releasing hormone promotes the release of
a.
b.
c.
d.
e.
follicle stimulating hormone.
growth hormone.
growth hormone releasing hormone.
prolactin.
prolactin releasing hormone.
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5. Which of the following mechanisms can increase the secretion of adrenocorticotropic
hormone from the anterior pituitary?
a.
b.
c.
d.
e.
An increase in corticotropin releasing hormone
A decrease in cortisol levels
A decrease in corticotropin inhibiting hormone
Two of the above increase the secretion of ACTH. (a and b)
All of the above increase the secretion of ACTH.
6. Which of the following describes the pattern of growth you might expect to see in a person
that never entered puberty, so that sex hormone levels stayed low throughout his lifetime?
a. The person would stop growing at the age when puberty should have started.
b. The person would continue growing at a moderate rate until the age when puberty
normally ends, when he would stop growing.
c. The person would continue growing at a moderate rate and growth would continue
until a later age than in a normal person.
d. The person would show an increase in growth rate at the age when puberty would
normally begin and would stop growing at the age when puberty normally ends.
e. The person would show an increase in growth rate at the age when puberty would
normally begin and would continue until a later age than in a normal person.
7. Which of the following components is/are part of the thick filaments?
a.
b.
c.
d.
e.
Actin
Myosin
Tropomyosin
Two of the above are part of the thick filaments.
All of the above are part of the thick filaments.
8. What would be the likely effects of a drug that caused the channels of the ryanodine
receptors of a muscle fiber to remain open permanently?
a.
b.
c.
d.
e.
The muscle would not contract at all.
The muscle would contract for a brief period of time and then relax again.
The muscle would alternate between contraction and relaxation in a cyclical fashion.
The muscle would contract indefinitely, or until it fatigued.
The thin filaments would fall to pieces.
9. During cross-bridge cycling, which of the following is the first event triggered by an ATP
molecule associating with a myosin molecule?
a.
b.
c.
d.
e.
The myosin head is energized.
The myosin binds to actin.
The myosin head moves to the low energy conformation.
The myosin head dissociates from the actin.
ATP does not affect myosin.
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10. An isolated muscle has a mass hanging from it that weighs less than the force the muscle can
produce. If the muscle is stimulated to produce a twitch contraction, which of the following
best describes what will happen?
a. The muscle will start shortening immediately.
b. The muscle will start shortening as soon as it starts producing force.
c. The muscle will start shortening as soon as it produces enough force to exceed the
weight (i.e. force) of the mass.
d. The muscle will not be able to shorten at all.
e. The muscle will not be able to shorten or contract.
11. Compared to a slow oxidative fiber, a fast glycolytic fiber has
a.
b.
c.
d.
e.
a greater density of capillaries.
more resistance to fatigue.
greater force production.
a greater density of mitochondria.
reduced glycogen stores.
12. In reference to muscle function, a motor unit is
a.
b.
c.
d.
e.
a single muscle fiber.
all the fibers innervated by a single motor neuron.
all the fibers of a particular type (SO, FO, or FG) in a muscle.
all the fibers in a muscle.
all the muscles attached to a particular bone.
13. The blood vessels with the smallest individual diameter are the
a.
b.
c.
d.
e.
arteries.
arterioles.
capillaries.
venules.
veins.
14. In contractile heart muscle, action potentials are
a.
b.
c.
d.
e.
a few milliseconds long and can stimulate tetanic contractions.
a few milliseconds long and cannot stimulate tetanic contractions.
over a hundred milliseconds long and can stimulate tetanic contractions.
over a hundred milliseconds long and cannot stimulate tetanic contractions.
Action potentials do not occur in cardiac muscle.
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15. During the heartbeat cycle, the atrioventricular valves close when
a. pressure in the atria exceeds pressure in the ventricles due to the relaxation of the
ventricles.
b. pressure in the atria exceeds pressure in the ventricles due to the buildup of blood
entering the atria from the veins.
c. pressure in the ventricles exceeds pressure in the atria due to buildup of blood
entering the ventricles from the atria.
d. pressure in the ventricles exceeding pressure in the atria due to the contraction of the
ventricles.
e. motor neurons activate the valve muscles.
16. During ventricular diastole, arterial pressure is maintained by
a.
b.
c.
d.
e.
active contraction of smooth muscle in the artery walls.
elasticity of the arterial walls.
increased vasoconstriction of arterioles.
compression of the arteries by adjacent skeletal muscles.
thinking happy thoughts.
17. According to Poiseuille’s Law, a doubling of the pressure gradient along a tube would cause
the flow to
a.
b.
c.
d.
e.
decrease to 1/16 its original value.
decrease to one-half its original value.
remain unchanged.
double its original value.
increase its original value by 16-fold.
18. If the total peripheral resistance of a healthy person were to increase by twofold, which of the
following physiological responses would be most likely?
a. Heart rate would stay about the same so that mean arterial pressure would increase by
about twofold.
b. Heart rate would stay about the same so that mean arterial pressure would decrease by
about twofold.
c. Heart rate would increase by about twofold so that mean arterial pressure would stay
about the same.
d. Heart rate would decrease by about twofold so that mean arterial pressure would
stay about the same.
e. Heart rate and mean arterial pressure would both be unchanged in response to the
increase in total peripheral resistance.
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19. Which of the following is not true about alveoli?
a.
b.
c.
d.
e.
They are the endpoint for the branching tubes that bring air into the lungs.
They are reinforced with cartilage.
They are the main location for gas exchange in the lungs.
They are each covered in a network of capillaries.
They increase and decrease in size as the lungs expand and contract.
20. As breaths become shallower (i.e., as tidal volume decreases), the alveolar ventilation rate
per breath
a.
b.
c.
d.
e.
decreases.
stays the same.
increases.
becomes negative.
Thank goodness the multiple choice is done.
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