Biology 449 - Animal Physiology Spring 2004

Midterm 2

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.

1.      Fill in your scantron form:  (1 point)

·        Write and bubble in your name in the upper left (last name first).

·        If you wish to retrieve your exam score through the course web site, write and bubble in a secret code (i.e. a password) in the “Special Codes” section.  Be sure you remember it!

·        Follow any additional instructions provided in class.

·        Sign your form in the upper right.

a.      Ah-ite.

b. – e.  Fuggedaboudit.

2.      Hyperactivity would most likely be associated with

a.      hypersecretion of thyroid stimulating hormone.

b.      hyposecretion of thyrotropin releasing hormone.

c.       hyporesponsiveness to thyroid hormones.

d.      Two of the above.

e.       All of the above.

3.      Growth hormone levels are generally

a.       lower during childhood, higher during puberty, and then moderate in older adults.

b.      moderate during childhood, and then higher during puberty and in older adults.

c.       moderate during childhood, higher during puberty, and then lower in older adults.

d.      higher during childhood and puberty, and then moderate in older adults.

e.       higher during childhood, moderate during puberty, and then lower in older adults.

4.      Which of the following is not associated specifically with increased release of calcitonin?

a.       decreased release of calcium from the bones.

b.      increased secretion of calcium by the kidneys.

c.       decreased uptake of calcium by the intestines.

d.      Two of the above.

e.       All of the above are associated specifically with increased release of calcitonin.

5.      A myofibril is

a.       a bundle of muscle cells.

b.      an individual muscle cell.

c.       a bundle of thick and thin filaments.

d.      one thick or thin filament.

e.       an individual myosin molecule.

6.      Dihydropyridine (DHP) receptors are directly activated by which of the following events?

a.       Acetylcholine release.

b.      Voltage changes in the T-tubules.

c.       Conformation changes in the ryanodine receptors.

d.      Calcium release from the sarcoplasmic reticulum.

e.       Cross-bridge cycling.

7.      During cross-bridge cycling in a muscle, which of the following occurs immediately before myosin binds to actin?

a.       ATP binds to myosin.

b.      ATP is converted to ADP, changing the conformation of myosin.

c.       Myosin releases ADP.

d.      Ca2+ binds to myosin.

e.       Ca2+ binds to actin.

8.      If you injected a muscle cell with a toxin that blocked the normal site of calcium binding on troponin, but did not active activate the troponin, which of the following would likely occur?

a.       The muscle would immediately begin contracting, and would contract continuously until ATP ran out.

b.      The muscle would not contract until an action potential occurred, but then would contract continuously until ATP ran out.

c.       A rigor mortis like state would immediately occur, with the actin and myosin locked together.

d.      No contraction would be possible.

e.       The muscle would contract and stop contracting in the normal manner.

9.      In a muscle given continuous stimulation by rapid, repeated action potentials

a.       force production increases quickly, and then drops off again almost as quickly.

b.      force production increases quickly, then plateaus, but typically declines again after a while.

c.       force production increases quickly, then plateaus, and will continue at that level indefinitely as long as the muscle is stimulated.

d.      force production increases very slowly, and will only reach a plateau after a long time.

e.       The muscle will fail to produce force at all, due to overstimulation.

10.  A muscle containing mainly fast glycolytic fibers is likely to exhibit relatively

a.       slow contraction velocity, low production, and many capillaries.

b.      fast contraction velocity, low force production, and many capillaries.

c.       fast contraction velocity, high force production, and many capillaries.

d.      fast contraction velocity, low force production, and few capillaries.

e.       fast contraction velocity, high force production, and few capillaries.

11.  Which of the following correctly describes the likely effects of weight training?

a.       Slow oxidative fibers will be converted to fast oxidative or glycolytic fibers.

b.      Fast oxidative or glycolytic fibers will be converted to slow oxidative fibers.

c.       Muscle fibers will proliferate to increase total muscle force production.

d.      Individual muscle fibers will increase in size to increase total muscle force production.

e.       Two of the above.

12.  Based on what you know about the pattern of blood circulation in mammals, which of the following arteries should carry deoxygenated blood?

a.      Pulmonary artery

b.      Coronary artery

c.       Subclavian artery

d.      Carotid artery

e.       Iliac artery

13.  The pacemaker cells in the heart are

a.       typical neurons.

b.      neurons, but different from typical neurons.

c.       typical myocardial cells.

d.      myocardial cells, but different from typical myocardial cells.

e.       not cells at all.

14.  Starling’s “Law of the Heart” states that

a.       heart rate increases as the quantity of blood returned to the heart increases.

b.      heart rate increases as the quantity of blood returned to the heart decreases.

c.       stroke volume increases as the quantity of blood returned to the heart increases.

d.      stroke volume increases as the quantity of blood returned to the heart decreases.

e.       you always hurt the one you love.

15.  Which of the following would not be expected to increase blood flow through an arteriole in the small intestine, assuming no other changes occur?

a.       Increased heart rate.

b.      Increased stroke volume.

c.       Active hyperemia in response to increasing levels of carbon dioxide.

d.      Decreased sympathetic stimulation of the arteriole.

e.       Increased release of epinephrine.

16.  Lymph formation occurs because, on average,

a.      the hydrostatic pressure gradient out of the capillaries exceeds the osmotic pressure gradient into the capillaries.

b.      the hydrostatic pressure gradient into the capillaries exceeds the osmotic pressure gradient out of the capillaries.

c.       the osmotic pressure gradient out of the capillaries exceeds the hydrostatic pressure gradient into the capillaries.

d.      the osmotic pressure gradient into the capillaries exceeds the hydrostatic pressure gradient out of the capillaries.

e.       None of the above.

17.  Cartilage provides reinforcement for the

a.       trachea.

b.      bronchi.

c.       bronchioles.

d.      Two of the above.

e.       All of the above.

18.  Which of following statements about the pulmonary system is true?

a.       both the rib cage itself and the lungs have a natural tendency to contract.

b.      both the rib cage itself and the lungs have a natural tendency to expand.

c.       the rib cage has a natural tendency to expand while the lungs have a natural tendency to contract.

d.      the rib cage has a natural tendency to contract while the lungs have a natural tendency to expand.

e.       Neither the rib cage nor the lungs can expand or contract, as any fool knows.

19.  Based on your knowledge of the respiratory system and the laws of flow, which of the following should be the result of constriction of the bronchioles, such as results from asthma?

a.       The surface area for gas exchange will be reduced.

b.      It will require a greater pressure differential between the alveoli and the atmosphere to get the same flow rate of air into the lungs.

c.       The anatomical dead space will be increased.

d.      Two of the above.

e.       All of the above.

20.  The partial pressure of carbon dioxide in the alveoli, arteries and veins is about (respectively)

a.       104, 104, and 40 torr.

b.      104, 46, and 40 torr.

c.       46, 40 and 40 torr.

d.      40, 46 and 46 torr.

e.       40, 40 and 46 torr.

21.  The volume of blood that consists of red blood cells is about

a.       5%.

b.      20%.

c.       45%.

d.      65%.

e.       80%.

22.  At rest, about what percent of the total oxygen carried by hemoglobin is delivered to tissues?

a.      25%

b.      50%

c.       75%

d.      85%

e.       98%

23.  An increase in which of the following would cause a left shift in the oxygen saturation curve?

a.      pH

b.      PCO2

c.       Temperature

d.      2,3-DPG

e.       All of the above would cause a left shift.

24.  The conversion of carbon dioxide to bicarbonate ion in the blood depends on the catalytic activity of

a.       carbamino compounds.

b.      amino groups.

c.       carbonic acid.

d.      carbonic anhydrase.

e.       carboxyl groups.

25.  The “pacemaker” of ventilation is currently identified as

a.       the respiratory center of the medulla.

b.      the respiratory center of the hypothalamus.

c.       the central pattern generator of the medulla.

d.      the central pattern generator of the hypothalamus.

e.       some squishy thing in the brain.

26.  A drop in arterial PO2 of 15 torr below normal does not bring about a strong ventilatory response, probably mainly because

a.       anaerobic metabolism can make up for a drop in oxygen levels.

b.      tissues can just extract more oxygen from hemoglobin by letting their PO2 levels drop.

c.       the chemoreceptors for oxygen are relatively insensitive.

d.      the drop is not sufficient to affect hemoglobin saturation much.

e.       oxygen is for sissies.

 

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.

27.  Briefly explain what causes the pattern of force production in each section of the length-tension relationship for a sarcomere, as shown below.


a.      

b.     

c.      

d.     



28.  The graph on the left shows a series of isotonic contractions, with the weight (in N) lifted by the muscle indicated for each contraction. Using the information in the left graph, reconstruct an isometric contraction for the muscle in the graph on the right.  You only need to show the contraction (i.e. increasing force) portion of the isometric curve, and only as far as you can take it with the available data. From left to right, the curves represent shortening when lifting a load of 0.0, 0.5, 1.0, 1.25 and 1.5 N.


29.  Describe the mechanical events in the left side of the heart during systole and diastole.  Be sure to indicate what is happening with blood flow, blood pressure, and valve activity.


















30.  Discuss the effects of the autonomic nervous system and epinephrine on cardiac output.










31.  While snorkeling in the Bahamas over spring break, your mind naturally turns to Bio 449, and you start thinking about anatomical dead space and alveolar ventilation.  If your snorkel holds 100 ml of air, and you have a typical anatomical dead space, what will be your a) minute ventilation and b) alveolar ventilation, if you are taking 10 breaths/min of 700 ml tidal volume?

a.       Minute ventilation


b.      Alveolar ventilation



32.  The oxygen saturation curves below are for myoglobin (upper curve) and hemoglobin (lower curve).  Solutions of each pigment are prepared such that at maximum saturation each solution holds 100 ml of oxygen.  Each solution is then exposed to an oxygen level such that the hemoglobin solution has 50 ml O2 per liter and the myoglobin solution has 90 ml O2 per liter.  (Ignore oxygen dissolved in the water for this problem.)


a.       What is the approximate partial pressure of oxygen in the hemoglobin solution?


b.      What is the approximate partial pressure of oxygen in the myoglobin solution?


c.       If the two solutions are exposed to one another, in which direction (if any) will net diffusion of oxygen occur, and why?