1)Describe the application of homeostasis to animals.

2)Describe the fundamentals of osmoregulation and excretion.

3)In what taxanomic group would you place a fish with the following plasma charactics? mOsm ~ 1,000, [Na⁺] ~ 550 mEq/L, [Cl^-] ~ 530 mEq/L. We suspect that the fish should be in which major taxanomic group?

4)Would you expect this fish to be an osmoconformer, osmoregulator, etc.?

5)What do we call animals that are able to let the end product of amino acid (protein) metabolism dissipate directly into the environment?

6)What kinds of membrane pumps to actively excrete are found in animal cells?

7)What is regulated by output from the juxtaglomerular apparatus?

8)What animals have the longest loops of Henle?

9)Why is the design of gas exchange structures is so critical?

10)Experient: We set up an experiment with two tubes, one filled with water (tube-H₂O) and one filled with air (tube-air). Initially, each tube is equilibrated with 100% N₂. At the beginning of the experiment we supply the source end of each tube with a PO₂ = 302.49 torr. Then we monitor the appearance of O₂ at the sink end of each tube. What kinds of results can we expect to find in this experiment?

11)What features do all gas exchange systems (ex., gills, lungs, trachea) have in common?

12)What gas exchange features are associated with fast swimming highly aerobic fish such as tuna?

13)Based on our understanding of the Fick diffusion equation we know that insects are unique because they take advantage of what?

14)Describe gill ventilation in a fish, example fresh water bass or trout, at rest.

15)A type of gas exchange system called a 'tidal pool' is found in what animals?

16)Surface area in the mammal lung is increased by what mechanisms?

17)What is Surfactant?

18)What animals have a gas exchange system with a fixed-volume lung surrounded by elastic air sacs?

19)What information is given by the following equation?

20)What happens to carbon dioxide in water?

21)Imagine a swordfish swimming in the open ocean at 50 mph. We sample arterial blood and find the PO₂ = 75 mmHg. From this we can guess that the blood P_CO2 is what value?

22)Imagine a cheetah running at 50 mph. We sample arterial blood and find the PO₂ = 75 mmHg. From this we can guess that the blood P_CO2 is what value?

23)In fish short-term homeostasis of ventilatory gas exchange is focused on what gas?

24)In lizards short-term homeostasis of ventilatory gas exchange is focused on what gas?

Essay - Describe how the vertebrate juxtamedullary nephron works in osmoregulation-excretion. To answer this question you will need to a.draw [include labels] a nephron, b.explain how the process of clearance works, c.describe the process of ‘water fine tuning.’ [Remember, since this is an essay you need to explain processes rather than listing steps].

1. Homeostasis, such as clearance of urea via the nephron always works directly on:

a)intracellular fluid.

b)tissue fluid.

c)plasma.

d)fluids found in clearance vesicles.

e)the fluids of the renal pelvis.

2. The total osmotic pressure of a marine hagfish plasma is about:

a)150 mOsm.

b)350 mOsm.

c)550 mOsm.

d)800 mOsm.

e)1,100 mOsm.

3. Relative to the Hagfish environment we should call this plasma osmolarity:

a)hypoosmotic.

b)hyperosmotic.

c)isosmotic.

d)hypoosmotic with respect to K⁺, but hyperosmotic with respect to Na⁺.

e)hyperosmotic with respect to K⁺, but hypoosmotic with respect to Na⁺.

4. Elasmobranchs [sharks, etc] maintain total plasma osmolarity similar to sea water by:

a)replacing monovalent cations with equal amounts of divalent cations.

b)replacing monovalent cations with equal amounts of monovalent anions.

c)substituting cellular monovalent cations with trimethylamine oxide.

d)substituting plasma monovalent cations with urea.

e)both 'a' and 'd' are necessary.

5. A fish that can survive a wide range of mOsm, but does not regulate mOsm internal fluids is a:

a)stenohaline osmregulator.

b)stenohaline osmoconformer.

c)euryhaline osmoregulator.

d)euryhaline osmconformer.

e)none of the above are appropriate.

6. While working at a research station you examine a barometer and find the pressure 500 mmHg. From this you calculate the PO₂ is about:

a)10.475 torr b)0.2095 torr c)20.95 torr

d)104.75 torr e)209.5 torr

7. You email the PO₂ value to a friend who right away knows that your station is:

a)at sea level; eg., San Diego.

b)above sea level; eg., Denver or higher.

c)below sea level; eg., Death Valley.

d)in an artificial environment such as the biosphere because the PO₂ is higher than atmospheric.

e)either 'c' or 'd' because these would both produce the same value for PO₂.

8. Countercurrent exchange is important to the function of the:

a)fish buccal pump.

b)fish lamellae.

c)avian air sacs.

d)mammalian alveolus.

e)all of the above.

9. Small alveoli do not collapse into larger alveoli because:

a)air pressures in small alveoli are higher than the pressures in the larger alveoli.

b)the Law of LaPlace shows that larger alveoli should tend to force air into smaller alveoli thereby keeping them inflated.

c)rapid diffusion of gases in air-filled spaces insures the alveoli will remain inflated.

d)surface active agents secreted by lung cells prevents surface tension from collapsing the smaller alveoli.

e)the actin-myosin webbing that lines alveoli prevents collapse.

10. The average diffusion distances for gases between respiratory surface and blood in all organisms with gas exchange structures [gills, lungs] is about:

a)1 - 5 microns.

b)20 - 50 microns.

c)100 - 500 microns.

d)2,000 - 5,000 microns.

e)10,000 - 50,000 microns.

11. A hypothetical aquatic organism living in well-aerated water with P_O2 = 150 mmHg has a metabolic rate = 10 mL O₂/h, RQ = 1.0, and tissue P_O2 = 100 mmHg. We should expect the tissue P_CO2 to be: