Download Midterm 2 - Creighton Biology

Name: __________________________
Biology 449 - Animal Physiology
Spring 2007
Midterm 2
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. Paracrine agents reach their target cells via
a.
b.
c.
d.
e.
diffusion
transport in vesicles.
transport in the bloodstream.
transport in the lymph.
transport through ducts.
2. In which chemical category do most known hormones fall?
a.
b.
c.
d.
e.
Amines
Glycoproteins
Peptide hormones
Prostaglandins
Steroid hormones
3. Which of the following mechanisms can change the amount of hormone being released by a
gland?
a.
b.
c.
d.
e.
Changes in the action potential frequency in neurons that innervate the gland.
Changes in the levels of a tropic hormone that affects the gland.
Detection by the gland itself of changes in the internal environment.
Two of the above.
All of the above.
4. The main response to cortisol (in natural animal populations) could best be described as
helping to ensure that an animal
a.
b.
c.
d.
e.
can keep fueling cellular activity when it may have limited access to food.
deposits large fat stores in case future access to food is limited.
has increased its metabolic rate to a level that can support increased activity.
has adequate blood flow to essential tissues when faced with dangerous conditions.
does not get infected with a pathogen when it can least afford it.
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5. Given what you know about thyroid hormones, which of the following is the most likely
mechanism by which they help increase Na+/K+-ATPase activity?
a. The hormones bind to and activate Na+/K+-ATPases already present in the cell
membrane.
b. The hormones activate G-protein complexes that directly activate Na+/K+-ATPases
already present in the cell membrane.
c. The hormones activate G-protein complexes that activate secondary messengers that
activate Na+/K+-ATPases already present in the cell membrane.
d. The hormones activate G-protein complexes that activate secondary messengers that
promote the insertion of stored Na+/K+-ATPase into the cell membrane.
e. The hormones cause the increased production of mRNA for Na+/K+-ATPase, which
leads to the production and insertion of additional ATPase.
6. Which of the following terms best describes the general changes or activities promoted by
growth hormone?
a.
b.
c.
d.
e.
Increased metabolic rate
Decreased metabolic rate
Increased catabolic activity
Increased anabolic activity
Increased sex hormone levels
7. In muscle fibers, the myofibrils are composed of the main functional units of contraction.
These units are known as
a.
b.
c.
d.
e.
sarcolemmas.
sarcomeres.
sarcoplasms.
sarcoplasmic reticuli.
sarcotrons.
8. Cross-bridge cycling in muscles involves
a. reversible binding between actin and myosin, and changes in conformation of the
myosin.
b. reversible binding between actin and myosin, and changes in conformation of the
actin.
c. reversible binding between myosin and tropomyosin, and changes in conformation of
the myosin.
d. reversible binding between myosin and tropomyosin, and changes in conformation of
the tropomyosin.
e. mysterious forces beyond the power of humankind to understand.
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9. The dihydropyridine receptors in the T-tubules of skeletal muscle active ryanodine receptors
as part of the process triggering muscular contraction. The dihydropyridine receptors
themselves are triggered by
a.
b.
c.
d.
e.
neurotransmitter molecules.
changes in the diameter of the T-tubules.
changes in membrane potential.
the presence of Ca2+.
the absence of Ca2+.
10. In general, the heavier the load a muscle is lifting during a twitch contraction
a.
b.
c.
d.
e.
the less time it is able to lift the load.
the more slowly it lifts the load.
the less distance it lifts the load.
Two of the above.
All of the above.
11. In comparison to slow oxidative muscle fibers, fast glycolytic muscle fibers tend to have
a.
b.
c.
d.
e.
higher capillary density.
slower rates of fatigue.
more glycogen (the stored form of glucose).
more mitochondria.
more myoglobin.
12. To control the amount of sustained force they produce, muscles rely on
a.
b.
c.
d.
e.
the partial activation of each muscle fiber.
alternation between twitch and tetanic contractions.
opposing forces produced by antagonistic muscles.
activation of only some muscle fibers in the muscle.
reduced delivery of fuel to muscle fibers.
13. The blood vessels that experience the highest pressure are the
a.
b.
c.
d.
e.
systemic arteries.
systemic arterioles.
pulmonary arteries.
pulmonary arterioles.
capillaries.
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14. Action potentials in the sinoatrial node of the heart would not occur without
a.
b.
c.
d.
e.
stimulation by the sympathetic nervous system.
stimulation by the endocrine system.
stimulation by action potentials that are triggered by the atrioventricular node.
stimulation by action potentials from stretch receptors in the heart wall.
The sinoatrial node depolarizes spontaneously, without the need for external
stimulation.
15. Starling’s Law of the Heart states that
a.
b.
c.
d.
e.
The heart beats more quickly in response to decreased ventricular filling.
The heart beats more quickly in response to increased ventricular filling.
The heart ejects more blood in response to decreased ventricular filling.
The heart ejects more blood in response to increased ventricular filling.
If you hear a starling sing under a full moon, you are destined to meet your true love.
16. If the arterioles leading to the gastrointestinal tract were to dilate, which of the following
patterns would you most likely see as a result?
a. Increased bloodflow to the GI tract, and increased cardiac output and/or increased
vasoconstriction elsewhere.
b. Increased bloodflow to the GI tract, and decreased cardiac output and/or decreased
vasoconstriction elsewhere.
c. Decreased bloodflow to the GI tract, and increased cardiac output and/or increased
vasoconstriction elsewhere.
d. Decreased bloodflow to the GI tract, and decreased cardiac output and/or decreased
vasoconstriction elsewhere.
e. You would probably start vomiting up blood.
17. Which of the following substances can diffuse straight through the cell membranes of the
capillaries’ endothelium?
a.
b.
c.
d.
e.
glucose
Na+
proteins
oxygen
None of the above can diffuse straight through the endothelial membranes.
18. What happens to the lymph formed by leakage from the circulatory system?
a.
b.
c.
d.
e.
It remains in the interstitial space.
It is excreted by the kidneys.
It is exuded from the skin as sweat.
It leaks back into the circulatory system through the walls of the venules.
It is returned to the circulatory system through a separate set of vessels.
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19. At resting levels of ventilation, which of the following best describes what drives inhalation?
a.
b.
c.
d.
e.
Contraction of the external intercostal muscles.
Contraction of the internal intercostal muscles.
Contraction of the diaphragm.
Relaxation of the diaphragm.
Two of the above.
20. As inhalation proceeds, the intrapleural pressure
a.
b.
c.
d.
e.
becomes more negative.
becomes less negative.
reaches zero.
becomes positive.
stays constant.
Short answer: Write a concise answer to each of the following questions. Your answers
should fit in the spaces provided. Diagrams may be used but must be accompanied by
written explanations. Each question is worth 8 points.
21. Complete the following table for the hypothalamic-pituitary system by filling in the blanks
with the appropriate hormones. Be sure to provide the full name of each hormone, not the
abbreviation.
Hypothalamus
Target Organ or Tissue
and Effects
Anterior Pituitary
→
→
Adrenal cortex
Cortisol release
→
→
Thyroid hormone
T3/T4 release
→
→
Breasts
Development, milk production
→
→
General body tissues
Growth and repair

Liver
IGF-1 release
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22. Consider a twitch versus a tetanic isometric contraction and answer the following:
a. What is the trigger or signal that causes a muscle to contract in a twitch versus tetanic
manner?
b. What is the difference in the contraction of a twitch versus tetanus? You are welcome to use
a figure to illustrate your answer, but be sure to explain the pattern as well.
c. Given what you know about how contraction is controlled, what is occurring inside the
muscle cells that cause the differences you described in “b” above?
23. The following questions relate to anatomical dead space (ADS) and pulmonary ventilation.
a. What physical structures make up the ADS?
b. In a person with an ADS of 150 ml who is breathing by taking breaths of 550 ml at a rate of
10 breaths per minute, what is the person’s
Tidal volume:
Alveolar ventilation rate:
Minute ventilation:
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24. Describe the three pathways or mechanisms that help to control arteriole diameter. Be clear
about whether diameter is increased or decreased in each example.
25. Describe the mechanical events that occur in the heart during ventricular diastole. Your
discussion should cover pressure and flow of blood and valve activity, and should explain
how these events are related. You do not need to discuss pacemakers, AP’s, etc.
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