Midterm 3

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 as follows:  (1 point)

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

·        If you wish to retrieve your exam score through the course web site and did not give me a PIN previously, write and bubble in a secret code (i.e. a PIN or password) in the “Special Codes” section.  Be sure you remember it!

·        Sign your form in the upper right.

a.       All right, already.

b. – e.  Make me!

2.      A triglyceride molecule consists of

a.       a glycerol and a fatty acid.

b.      three glycerols and a fatty acid.

c.       a glycerol and three fatty acids.

d.      three gycerols and three fatty acids.

e.       None of the above.

3.      With regard to the processing of food, the mouth functions to

a.       mechanically break down the food.

b.      digest the food.

c.       absorb the food.

d.      Two of the above.

e.       All of the above.

4.      Gastrin levels in the blood would drop in response to

a.       increased distention of the stomach.

b.      increased levels of peptides in the stomach.

c.       increased acidity in the stomach.

d.      decreased levels of fats in the stomach.

e.       decreased levels of secretin in the blood.

5.      Glucose absorption by the small intestine involves

a.       permeation of glucose across the apical (lumen-side) membrane.

b.      facilitated diffusion of glucose across the apical membrane.

c.       active transport of glucose across the apical membrane, via glucose ATPase.

d.      active transport of glucose across the apical membrane, via glucose/Na⁺ ATPase.

e.       secondary active transport of glucose across the apical membrane, via cotransport with Na⁺.

6.      Most water in the gastrointestinal tract is absorbed by

a.       the stomach.

b.      the small intestine.

c.       the large intestine.

d.      the liver.

e.       the kidneys.

7.      Most adults have conscious control over their

a.       mass movements.

b.      internal anal sphincter.

c.       external anal sphincter.

d.      Two of the above.

e.       All of the above.

8.      During the absorptive state, the primary source of fuel for body cells is

a.       glucose.

b.      glycogen.

c.       proteins.

d.      fats.

e.       ketones.

9.      Fat cells release fatty acids in response to

a.       high insulin levels.

b.      low insulin levels.

c.       high glucagon levels.

d.      low glucagon levels.

e.       Two of the above.

10.  “Excretion” can best be described as

a.       urination.

b.      defecation.

c.       formation of nitrogenous wastes.

d.      transfer of substances from the body’s internal environment to the external environment.

e.       formation of a fluid by ultrafiltration.

11.  Which of the following is not a function of the renal system?

a.       Water volume regulation

b.      Ion regulation

c.       pH regulation

d.      Two of the above are not functions of the renal system.

e.       All of the above are functions of the renal system.

12.  A substance “Q” is present in the blood plasma and is being filtered into the nephron.  The glomerular filtration rate is 100 ml/min and Q is present at 1 mg/ml in the initial filtrate.  If the final urine production is 1 ml/min with Q present at 10 mg/ml, we can surmise that

a.       Q was secreted into the nephron.

b.      Q was reabsorbed from the nephron.

c.       Q was neither secreted nor reabsorbed.

d.      the urine is supersaturated with Q.

e.       Q is not a substance normally found in the mammalian body.

13.  The thin ascending limb of the loop of Henle

a.       is impermeable to water and salt (Na⁺)

b.      is permeable to water but impermeable to salt

c.       is impermeable to water but passively permeable to salt.

d.      is impermeable to water but salt is actively transported out.

e.       is permeable to water and salt is actively transported out.

14.  The concentration of urine in the distal tubule is usually about

a.       0 – 100 mOsm.

b.      100 – 300 mOsm.

c.       100 – 1400 mOsm.

d.      300 mOsm.

e.       300 – 500 mOsm.

15.  If someone was injected with an agent that permanently activated the ADH receptors in his kidneys, which of the following would be a likely effect?

a.       He would have to use the bathroom a lot.

b.      He would be really thirsty.

c.       His own ADH production would increase.

d.      His blood volume would increase.

e.       His body fluids would get more concentrated.

16.  Aldosterone

a.       promotes the reabsorption of sodium in the proximal tubule.

b.      promotes the secretion of sodium in the proximal tubule.

c.       promotes the reabsorption of sodium in the distal tubule.

d.      promotes the secretion of sodium in the distal tubule.

e.       promotes increased water reabsorption in the collecting duct.

17.  Which of the following would help cope with an increase in blood pressure above normal?

a.       Reduced cardiac output.

b.      Increased peripheral resistance.

c.       Increased ADH release.

d.      Increased renin release.

e.       Decreased ANF release.

18.  Blood volume affects cardiac output primarily by directly influencing

a.       heart rate.

b.      peripheral resistance.

c.       arterial blood pressure.

d.      capillary blood pressure.

e.       venous blood pressure.

19.  During your first day as a medical intern, you asked to help diagnose a person with unusually alkaline urine.  What might this renal compensation be in response to?

a.       Decreased ventilation.

b.      A severe case of diarrhea.

c.       Too much anaerobic activity.

d.      An Atkins diet type meal, laden with protein.

e.       A large dose of sodium bicarbonate taken for an upset stomach.

20.  During puberty in human females, secondary hair growth

a.       is promoted by and its pattern determined by androgens.

b.      is promoted by and its pattern determined by estrogen.

c.       is promoted by androgens but its pattern determined by estrogen.

d.      is promoted by estrogen but its pattern determined by androgens.

e.       None of the above.

21.  In stimulating the Sertoli cells, testosterone is acting as a

a.       autocrine agent.

b.      paracrine agent.

c.       hormone.

d.      secondary messenger.

e.       neurotransmitter.

22.  If a man’s Sertoli cells over-produced inhibin, which of the following would likely be seen?

a.       Low levels of FSH.

b.      Low levels of LH.

c.       Low levels of GnRH.

d.      Two of the above.

e.       All of the above.

23.  Fluid secreted prior to ejaculation is produced primarily by the

a.       epididymis.

b.      seminal vesicle.

c.       prostate gland.

d.      bulbourethral gland.

e.       ejaculatory duct.

24.  Viagra is a drug used to help combat impotence in some men.  (Impotence is the inability to produce or sustain an erection.)  Given what you know about human physiology, which of the following is a possible mechanism for the effects of Viagra?

a.       It causes increased sympathetic stimulation of the penile arterioles.

b.      It causes increased vasodilation of the penile arterioles.

c.       It causes increased sympathetic stimulation of the penile veins.

d.      It causes increased vasodilation of the penile veins.

e.       It all psychological.

25.  The theca of a maturing follicle produce

a.       estrogen.

b.      progesterone.

c.       androgens.

d.      inhibin.

e.       luteinizing hormone.

26.  During the menstrual phase, the endometrium dies off due most directly to 

a.       a drop in luteinizing hormone levels.

b.      a drop in follicle-stimulating hormone levels.

c.       thickening mucus in the uterus.

d.      increased glandular activity in the endometrium.

e.       decreased blood flow to the endometrium.

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.  Describe the negative feedback loop(s) involving cholecystokinin.  You are welcome to use a diagram, but be sure that causes and effects are clear and complete.

28.  Describe the process by which fats are digested and absorbed.  (Assume that lipases have already been released.)  Again, you are welcome to use a diagram, but be sure that events are explicitly described somewhere.  You may end your discussion at the point when the absorbed fats enter the lymphatic system.

29.  Describe the process of reabsorption of sodium, glucose, water and urea in the proximal tubule.  Without wanting to beat this to death, you are welcome to use a diagram, but be sure that you make clear the general mechanisms involved for each substance.  You do not need to discuss the details of the pathways taken by the solutes through and between cells.

30.  List two ways in which the juxtaglomerular apparatus helps control kidney function.  One or two sentences is sufficient explanation for each.

31.  In testicular feminization, neither the male nor female internal reproductive tracts develop in a genetically male fetus.  Why is this?

32.  Answer the following questions using the graph below. (6 points)

a.       The graph needs to show the relative levels of luteinizing hormone, estrogen and progesterone during the female menstrual cycle.

·        Label the existing line as one of these three hormones.

·        Add the lines for the remaining two hormones to the graph, and label each line.  (Note: it is only the change of each hormone through time that is important, not the absolute levels of the hormones to one another.)

b.      For each of the following events, place the corresponding number at the appropriate time on the graph.

1 - Corpus luteum starts degenerating
2 - Positive feedback loop for estrogen release begins
3 - The follicles begin developing
4 - Ovulation occurs
5 - Menstrual phase of uterine cycle