| Biology 449 - Animal Physiology | Spring 2003 |
Multiple choice: As always, choose the best answer for each multiple-choice question. Answer on your scantron form. Each question (except 1) is worth 3 points.
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a. Okely-dokely
b. – e. ¿Que?
2. Which of the following would not be considered part of the body’s “internal environment”?
a. The interstitial fluid.
b. The blood.
c. Chyme in the small intestines.
d. Two of the above are not part of the “internal environment.”
e. All of the above are considered part of the “internal environment.”
3. In a negative feedback loop, if the regulated variable increases above the setpoint, the effect of an effector should be to
a. increase the variable.
b. decrease the variable.
c. maintain the variable at its new value.
d. change the setpoint.
e. It depends on whether the effector controls influx or efflux.
4. For an uncharged particle X, the initial direction and rate of diffusion of X from A across a membrane to B depends on
a. the concentration of X in A and B.
b. the charge across the membrane.
c. the osmotic concentration of A and B.
d. Two of the above.
e. All of the above.
5. If a cell with a water-permeable membrane is significantly hypertonic to its environment, it will likely
a. shrivel.
b. maintain its current volume.
c. burst.
d. More information is needed on the permeability of the membrane to the solutes.
e. More information is needed on the permeability of the membrane to the solutes and the solute concentrations.
6. Which type of cell would not be expected to exhibit an action potential?
a. An afferent neuron.
b. An interneuron.
c. A motor neuron.
d. A glial cell.
e. A muscle cell.
7. The Nernst equation is usually inappropriate for determining cell membrane potentials in “real life” situations because
a. the Nernst equation cannot be related to cell membranes.
b. the Nernst equation is only for uncharged particles.
c. the Nernst equation cannot handle divalent ions.
d. the Nernst equation cannot be used when more than one ion is present.
e. the Nernst equation cannot be used when the membrane is permeable to more than one ion.
The channels would open and stay open.
b. The channels would open, close and then open again.
c. The channels would open, and then close and stay closed.
d. The channels would never open.
e. Neurons don’t contain voltage-gated sodium channels.
9. In a myelinated axon, the nodes of Ranvier
a. initiate the action potential in the axon.
b. provide insulation for the axon.
c. are the site where action potentials occur along the axon.
d. are the site of synaptic transmission.
e. Myelinated axons do not have nodes of Ranvier.
10. If an excitatory presynaptic neuron and an inhibitory presynaptic neuron were both activated at the same time, the effect on the post-synaptic neuron would be
a. depolarization of the membrane above threshold.
b. depolarization of the membrane, but below threshold.
c. no net change in membrane voltage.
d. hyperpolarization of the membrane.
e. Impossible to tell from the information given.
11. A sensory neuron that shows very rapid adaptation is known as a(n)
a. adaptive receptor.
b. tonic receptor.
c. phasic receptor.
d. spike-initiating receptor.
e. Sensory neurons do not show adaptation.
12. Generally, the receptor membrane region of a sensory neuron
a. exhibits no direct response to the environmental stimulus.
b. exhibits a graded response in membrane potential in response to the environmental stimulus.
c. exhibits action potentials at a rate proportional to the environmental stimulus.
d. exhibits action potentials with an amplitude proportional to the environmental stimulus.
e. exhibits action potentials with a duration proportional to the environmental stimulus.
13. The sensory cells involved in both hearing and equilibrium are known as
a. audiocytes.
b. otoliths.
c. Pacinian corpuscles.
d. Corti cells.
e. hair cells.
14. The sex hormones are classified as
a. prostaglandins.
b. catecholamines.
c. peptide hormones.
d. steroid hormones.
e. amines.
15. A hormone gland that is actually modified neural tissue is the
a. anterior pituitary.
b. posterior pituitary.
c. thyroid gland.
d. parathyroid gland.
e. adrenal cortex.
16. Thyroid stimulating hormone controls the release of
a. dopamine.
b. growth hormone releasing hormone.
c. growth hormone.
d. thyroid hormone.
e. thyrotropin releasing hormone.
17. One effect of increasing levels of parathyroid hormone is
a. increased release of calcium by the bones.
b. increased secretion of calcium by the kidneys.
c. decreased intestinal absorption of calcium.
d. Two of the above.
e. All of the above.
18. A sarcomere
a. is a muscle cell.
b. supplies the ATP for the muscle cell.
c. stores and releases Ca2+.
d. carries action potentials deep into the muscle cell.
e. produces force.
19. During cross-bridge cycling, ATP attaches
a. to actin when actin and myosin are attached to each other.
b. to actin when actin and myosin are not attached to each other.
c. to myosin when actin and myosin are attached to each other.
d. to myosin when actin and myosin are not attached to each other.
e. None of the above.
20. Muscles with high myosin-ATPase activity would be classified as
a. fast glycolytic.
b. fast oxidative.
c. slow oxidative.
d. a and b
e. b and c
21. Reasons for decreased muscular performance as a result of fatigue include
a. lactic acid buildup.
b. exhaustion of glycogen stores.
c. acetylcholine depletion (a.k.a. neuromuscular fatigue).
d. Two of the above.
e. All of the above.
22. Ventricular systole is best defined as
a. the period when the ventricles are contracting.
b. the period when the ventricles are relaxed.
c. the period when blood is being ejected from the heart.
d. the period when the aortic semilunar valves are open.
e. the period when the atrioventricular valves are open.
23. According to Poiseuille’s law, flow through a tube is proportional to the radius raised to the power of
a. ¼
b. ½
c. 1
d. 2
e. 4
24. At rest, exhalation is driven by
a. elastic contraction of the rib cage.
b. elastic contraction of the lungs.
c. elastic expansion of the diaphragm.
d. muscular contraction of the internal intercostals.
e. muscular contraction of the diaphragm.
25. Given that overall ventilation rate (ml/min, also known as minute ventilation) is held constant, an increase in tidal volume will result in
a. a decrease in alveolar ventilation rate.
b. no change in alveolar ventilation rate.
c. an increase in alveolar ventilation rate.
d. The effect would depend on the overall ventilation rate.
e. The effect would depend on the amount of anatomical dead space.
26. The oxygen saturation curve for hemoglobin has a nearly horizontal aspect above about 90 torr (see question 58). The effect of this is that, over the range PO2 = 90 to 110 torr,
a. it is difficult to get oxygen to bind to hemoglobin.
b. oxygen is rapidly loaded or unloaded with a small change in PO2.
c. oxygen saturation changes little as PO2 changes.
d. A right-shift will substantially reduce oxygen saturation.
e. A left-shift will substantially reduce oxygen saturation.
27. Which of the following is not a major form of transport for carbon dioxide in the blood?
a. Dissolved carbon dioxide.
b. Bicarbonate ion.
c. Carbonic anhydrase.
d. Carbamino compounds.
e. All of the above are a form in which carbon dioxide is transported.
28. An increase in arterial PO2 above the normal level of 104 torr leads to what sort of change in ventilation, assuming PCO2 does not change?
a. Ventilation increases.
b. Ventilation stays the same.
c. Ventilation decreases.
d. It depends on the altitude.
e. It depends on the temperature.
29. Pepsin is activated in the stomach by the direct effects of
a. acidic secretions.
b. gastrin.
c. pepsinogen.
d. goblet cell mucus.
e. the parasympathetic nervous system.
30. The microvilli are part of which layer of the gastrointestinal “tube”?
a. Serosa
b. Muscle layer
c. Submucosa
d. Mucosa
e. Lumen
31. Upon leaving the GI tract, the first organ absorbed carbohydrates will encounter is the
a. pancreas.
b. liver.
c. kidneys.
d. heart.
e. lungs.
32. Which of the following cannot be converted into glucose by the human body?
a. Glycogen
b. Amino acids
c. Fatty acids
d. Two of the above cannot be converted into glucose.
e. All of the above can be converted into glucose.
33. A newly-formed drop of urine would pass through the different parts of the renal system in which order?
a. renal pelvis, renal cortex, renal medulla, urethra, ureter
b. renal medulla, renal cortex, renal pelvis, urethra, ureter
c. renal cortex, renal medulla, renal pelvis, urethra, ureter
d. renal medulla, renal cortex, renal pelvis, ureter, urethra
e. renal cortex, renal medulla, renal pelvis, ureter, urethra
34. Which of the following substances is typically completely reabsorbed in the proximal tubule?
a. Sodium chloride
b. Glucose
c. Urea
d. Water
e. None of the above are typically completely reabsorbed in the proximal tubule.
35. The end portion of the loop of Henle and the distal tubule is important for
a. a substantial reduction of the urine volume.
b. the creation of the glomerular filtrate.
c. the creation of a strong osmotic gradient in the medulla.
d. the creation of a hyposmotic urine.
e. the creation of a hyperosmotic urine.
36. The direct effects of angiotensin I include
a. increasing vasoconstriction.
b. promoting aldosterone release.
c. increasing water reabsorption by the kidney.
d. Two of the above.
e. None of the above.
37. The most direct effect of a drop in venous blood pressure is
a. a drop in arterial blood pressure.
b. a drop in heart rate.
c. a drop in stroke volume.
d. a drop in total peripheral resistance.
e. a drop in blood volume.
38. As part of the acute response to a drop in arterial blood pressure, which of the following would you expect to see?
a. An increase in sympathetic stimulation of the heart’s pacemakers (increasing heart rate).
b. An increase in sympathetic stimulation of the heart’s muscle (increasing stroke volume).
c. An increase in sympathetic stimulation of the arterioles (increasing vasoconstriction).
d. Two of the above.
e. All of the above.
39. A genetic male who lacked a functioning SRY gene would develop
a. male gonads, internal and external genitalia.
b. male gonads, no internal genitalia, and male external genitalia.
c. male gonads, no internal genitalia, and female external genitalia.
d. female gonads, internal and external genitalia.
e. female gonads, no internal genitalia, and female external genitalia.
40. In men, the final maturation of sperm takes place mainly in the
a. Sertoli cells.
b. seminiferous tubules.
c. epididymus.
d. ejaculatory duct.
e. female reproductive tract.
41. Which of the following is true concerning sexual activity in males?
a. Erection is promoted by parasympathetic activity, while ejaculation results from sympathetic activity.
b. Erection is promoted by sympathetic activity, while ejaculation results from parasympathetic activity.
c. Erection and ejaculation are both dependent on parasympathetic activity.
d. Erection and ejaculation are both dependent on sympathetic activity.
e. Neither of these activities depends on neural input.
42. In human females, meiosis of the oocyte(s) is completed
a. in the developing fetus.
b. during puberty.
c. during follicular development.
d. immediately after ovulation.
e. immediately after fertilization.
43. In women, progesterone levels peak
a. during early follicular development.
b. during late follicular development.
c. at ovulation.
d. during mid luteal phase.
e. during menstruation.
44. On average, once in the female reproductive tract
a. sperm and eggs both live about 12-24 hours.
b. sperm and eggs both live about 3-5 days.
c. sperm live 12-24 hours and eggs live 3-5 days.
d. sperm live 3-5 days and eggs live 12-24 hours.
e. sperm and eggs both persist indefinitely.
45. During parturition, the hormone primarily responsible for promoting uterine contractions is
a. follicle-stimulating hormone.
b. luteinizing hormone.
c. oxytocin.
d. prolactin.
e. inhibin.
46. The most common type of leukocyte are
a. basophils.
b. eosinophils.
c. lymphocytes.
d. monocytes/macrophages.
e. neutrophils.
47. The edema seen during the inflammatory response is due to
a. the cytosol released from damaged body cells.
b. anti-microbial secretions from macrophages.
c. increased leakage of lymph from capillaries.
d. changes in the osmotic concentration of inflamed tissues.
e. leakage of fluid from damaged sweat glands.
48. Which of the following describes the effects of interferon?
a. it prevents viri from successfully attaching to cell membranes.
b. it interferes with the injection of the viral genome into the cell.
c. it inhibits the synthesis of proteins key to viral replication.
d. it blocks mitosis in cancerous (and non-cancerous) cells.
e. it “turns off” leukocytes to end the inflammatory response.
49. The term “immunoglobins” includes
a. antibodies.
b. B cell antigen receptors.
c. T cell antigen receptors.
d. Two of the above.
e. All of the above.
50. Activated cytotoxic T cells kill other cells through the use of
a. antibodies.
b. perforin.
c. C3b.
d. the membrane attack complex.
e. Activated cytotoxic T cells do not kill other cells.
51. Plasma cells are involved in
a. the humoral response.
b. the cell-mediated response.
c. immunological memory.
d. non-specific defenses.
e.
acting as “sentinel” cells to signal tissue damage.
Short answer: Write a concise answer to each of the following questions. Your answers should fit in the spaces provided. Each question is worth 4 points.
When appropriate, you are welcome to use a diagram in your answer, but be sure all events and processes are made clear. If you are uncertain about the nature of the question, please ask!
52.
Provide three differences between nerves and hormones in term of their function
as effector pathways.
A nerve targets a specific organ or site, while a hormone spreads throughout
the body.
Nerves provide for nearly instant signaling; hormones take longer to reach their
targets.
The organ response to nerves tends to be rapid but shorter-lived, while hormones
tend to have slower-onset but longer-lived effects.
53.
Describe the process of synaptic transmission in a typical fast synapse.
An action potential arriving at the presynaptic neuron causes voltage-gated
calcium channels to open. The influx of calcium causes synaptic vesicles to
fuse with the neural membrane, releasing neurotransmitter into the synaptic
cleft. The neurotransmitter diffuses across the cleft and binds to ligand-gated
ion channels in the post-synaptic neuron. The resulting change in permeability
of the membrane to an ion changes the membrane polarity. A sufficiently strong
depolarization will result in an AP in the postsynaptic neuron. The neurotransmitter
is removed from the cleft through enzymatic breakdown and/or reuptake by the
presynaptic neuron.
54. Explain how light is transduced
by a photoreceptor cell, up to the point where membrane voltage is changed.
You may use any standard abbreviations, rather than complete molecular names,
when appropriate.
Rhodopsin molecules in the membranes of the lamellae react to light; a photon
absorbed by the retinal portion changes it from the cis to trans
form, and the retinal breaks loose from the opsin portion. As a result, the
opsin activates the G-protein transducin, which in turn activates PDE (phosphodiesterase).
PDE converts cGMP into 5’-GMP, which means that cGMP activated Na+
channels now close. This leads to a change in membrane polarity from depolarized
to hyperpolarized.
55. Describe the hormone pathway
involved in the stress response, and list two effects of the final hormone in
the pathway.
The response to stress is an increased release of corticotropin releasing
hormone by the hypothalamus, which triggers increased release of adrenocorticotropic
hormone by the anterior pituitary, which in turn causes an increased release
of cortisol by the adrenal cortex. Cortisol’s effects include the mobilization
of energy stores, breakdown of proteins, and inhibition of the immune system.
56. Briefly define an isometric
and isotonic contraction. Which label better applies to the activity of the
leg muscles during running?
An isometric contraction is one in which the muscle’s length does not change,
while an isotonic contraction is one in which the load on the muscle is constant.
During running, the contractions are more isotonic than isometric.
57.
List and briefly explain the three general pathways or mechanisms that
influence the stroke volume of the heart.
Stroke volume is influenced by the sympathetic nervous system (but not the
parasympathetic), with increased activity leading to increased stroke volume.
The endocrine system also influences stroke volume, with epinephrine, for
example, increasing stroke volume.
Stroke volume is also influenced by the volume of blood in the heart at the
start of the contraction (Starling’s law), with increased volume increasing
sarcomere length and thus contractile force.
58. An oxygen permeable membrane separates a sample of blood from an isotonic solution of NaCl in water. The hemoglobin in the blood is 80% saturated. (The oxygen saturation curve is shown below). The salt solution has an oxygen concentration of 4 ml O2/liter and an oxygen solubility of 0.04 ml/(liter•torr). In which direction will net oxygen diffusion occur? Show your work to justify your answer.
If Hb is 80% saturated, the PO2 of the blood must be about 40 torr. For the salt solution, PO2 = CO2 ÷ SO2 = 4 ml O2/liter2 ÷ 0.04 ml O2/(liter•torr) = 100 torr. Therefore, oxygen will diffuse from the salt solution into the blood.
59. For the pancreas:
a.
List two exocrine secretions.
Lipases, proteases, amylase, sodium bicarbonate
b. List
two endocrine secretions.
Insulin, glucagon
60. How does ADH control the concentration
of urine produced by the kidneys? You do not need to discuss the ADH
feedback loop, just its mechanism of action.
ADH promotes the insertion of aquaporins into the apical membrane of the
collecting duct epithelium. These channels allow water to pass through the
otherwise water-impermeable duct. As a result, water can be reabsorbed as the
urine travels down the collecting duct, with reabsorption being driven by the
increasing osmotic concentration outside the tubule.
61. Explain the effects of a sudden
metabolic alkalosis on the blood’s bicarbonate buffering system and the subsequent
effects on ventilation.
A metabolic alkalosis would mean a loss of H+. The result of
this would be a drop in (CO2 + H2O) as the H+
(+ HCO3-) increased again, with the blood buffering system
thus coming to a new equilibrium after the initial change in [H+].
(Note that, although H+ levels are less affected than they would
be without the buffering system, they still drop somewhat.) The drop in CO2
and H+ levels means that ventilation will decrease, driving up CO2
levels in the blood, thus helping to further increase H+ levels back
towards normal.
62.
During pregnancy, estrogen and progesterone must be kept at high levels
to maintain the endometrial layer of the uterus, among other functions. What
mechanisms keep these hormones at high levels in the maternal blood through
the pregnancy?
During the first three months or so of pregnancy, the embryo/fetus releases
chorionic gonadotropin, which promotes continued release of progesterone and
estrogen by the corpus luteum. The corpus luteum does not degenerate as long
as CG is present. At the end of this period, the placenta has begun production
of sufficient estrogen and progesterone so that production by the mother is
no longer required. (CG levels then drop off and the corpus luteum degenerates.)
63. Describe the process by which
helper T cells are activated. You do not need to discuss any of the
events that occur after this activation.
Helper T cells activation requires that several events occur. A foreign
antigen must be presented in the class II major histocompatibility complex of
a macrophage (or B cell), and this cell must encounter a helper T with a matching
antigen receptor. In addition, activation (usually) requires the release of
cytokines, such as interleukin-1 and/or tumor necrosis factor, by the macrophage.
Extra credit question (4 points)
During spring break, you find yourself relaxing in a hot tub with a water temperature of 39°C (compared to normal body temperature of 37°C). As your body temperature begins to rise…
a.
What would be some expected physiological responses, and how effective
would these be?
You’d respond as typical when body temperature rises – mainly increased cutaneous
blood flow and increased sweating. Sweating underwater doesn’t do you any good,
since no evaporation can occur, and increased cutaneous blood flow will actually
cause you to take in heat faster, since your blood is in closer contact with
the hot water. (We just haven’t evolved appropriate responses for this type
of situation!)
b.
Given your answer to a, what might be your heart’s response to
this hottubbing?
The hotter you get, the more blood flow is increased to the skin. This means
decreasing resistance in the skin’s arterioles and capillaries, which means
a decrease in overall peripheral resistance. To maintain BP, cardiac output
must increase. There are cases of people with bad hearts suffering heart attacks
from spending too much time in the hot tub.