REVIEW QUESTIONS IB 2002 – EXAM 2 2009 (ANIMAL SECTION)
1. Explain the environmental pathways of O2 and CO2. Where does O2 come from?
Where does CO2 come from? Why is CO2 a requirement for life on earth? Why is it a
potential problem for animals?
2. Describe the 4 types of respiratory surfaces discussed in class. Under what scenarios
is respiration through the skin effective? Under what scenarios is respiration through
gills effective? Under what scenarios is respiration through lungs effective? Under what
scenarios is respiration through a trachea effective? What are the limitations of each type
of respiratory surface? Do all of these respiratory surfaces rely on diffusion? In what
sense?
3. In the gills of fish, the blood flows in the opposite direction of the water. This called
a counter current exchange mechanism. What is the advantage of a counter-current
exchange mechanism over a concurrent exchange mechanism? Do human lungs have a
counter-current exchange mechanism in the alveoli of the lungs? Be able to draw the
graphs showing the difference between counter-exchange mechanism and a concurrent
exchange mechanism.
4. Lungless salamanders typically live in moist or humid habitats and can die if their skin
dries out. Explain why it is critical for the skin of a lungless salamander to remain moist.
5. In fish, there is a positive correlation between whole-animal metabolic rate and the
surface area of the gill. What might explain this relationship?
6. Describe the anatomy of the human respiratory system. Know the definitions of the
following words: alveoli, bronchus, bronchiole, trachea, lung. Where does gas exchange
occur in the lung? What is the relationship between surface area in the human lung
versus surface area of the body? List 2 important properties of the alveolus that allow for
gas exchange to take place.
7. What are surfactants? Why do lungs rely on surfactants over pure H2O?
8. How do the movements of the diaphragm control the direction of air flow in the
lungs? (Note we didn’t cover this in class, but this is well covered in your book.)
9. Describe respiration in the bird lung. Explain the difference between bird respiration
and mammalian respiration.
10. Very few animals that use water as the respiratory medium have lungs. Instead, most
water breathers use gills for gas exchange. What functional disadvantages do lungs have
in water?
11. A woman gets a disease that makes her unable to produce surfactant in her lungs. If
she has a normal tidal volume (i.e. amount of air moving in and out of her lungs), what
can you say about the intrapleural pressure (pressure exerted via the diaphragm) during
respiration?
12a. In an experiment to determine the role of air sacs in the avian lung, physiologists
tied off an air sac so that gas from the air sac could no longer enter the lung. The
experimenters then injected carbon monoxide into the sealed sac. This manipulation did
not decrease the O2 saturation in arterial blood. Explain why this was the case, and what
this experiment demonstrates about the nature of air sacs in birds.
12b. Why is diffusion an inefficient respiratory strategy for organisms that are more than
a few millimeters thick?
13a. Which environment has the highest concentration of O2? cold freshwater, warm
freshwater, cold saltwater, warm saltwater?
13b. Explain how respiration would occur in the absence of Hemoglobin (Hb).
14. Describe the chemical and anatomical pathways of CO2 and O2 between
blood/RBC/Hb and tissues in the body away from the respiratory sites. What is the role
of carbonic anhydrase in driving this reaction? How does the transport of HCO3- out of
the RBCs drive this reaction? Is carbonic anhydrase present in the RBC? Is carbonic
anhydrase present in the blood serum? What is the functional significance of the location
of this enzyme? What is the role of Hb binding in the diffusion of CO2?
15. Describe the chemical and anatomical pathways of CO2 and O2 between
blood/RBC/Hb and in the lungs. Hb+O2 <<-->> Hb-O2 +H+ ; how does the production
of H+ contribute to the release of CO2 in your lungs? How is O2 uploaded? What is the
role of carbonic anhydrase in driving CO2 out of your lungs?
16. What are the four forms CO2 takes in your blood? Describe the CO2/bicarbonate
pathway. What is the approximate ratio of each component in your blood? How does a
buffer work (this can be found on page 55 of your book)?
17. Explain the importance of the Bohr Shift in gas exchange. Which way does the
curve shift at the lungs? Which way does the curve shift at the tissues? What is the
importance of this? Draw the graph with loading & unloading of O2 in reference to the
Bohr shift.
18. Describe the properties of Hemoblobin in relation to O2 concentration and pH.
Describe how O2 and CO2 bind to Hb. Do they bind in the same place? Where do they
bind?
19. Explain how the differences in binding efficiency between fetal Hb and adult Hb
cause the flow of O2 from the mother to the baby.
20. Describe the adaptations of pronghorn antelope that allow them run for high speeds
for prolonged periods of time. Describe the adaptations of diving mammals that allow
them to stay underwater for as long as 2 hours.
21. What effects might you expect in a mammal whose major hemoglobin is mutated
such that it lacks a Bohr effect?
22. Metabolic rate can increase as much as 40-fold above resting values as a result of
feeding in some species of reptiles. In addition, during digestion, a large amount of H+ is
secreted into the stomach, which results in the so-called alkaline tide, a large metabolic
alkalosis in which blood pH increases. Outline the likely response of the respiratory
system to this increased oxygen demand and pH disturbance.
23. In fish, there is a positive correlation between whole-animal metabolic rate and the
surface area of the gill. What might explain this relationship?
24. Hemoglobin is typically saturated with oxygen when the blood leaves the lungs. In a
person who is doing pull ups, will hemoglobin release more of the bound oxygen in the
quadriceps (leg muscles) or in the biceps (arm muscles)? If so, please describe at least
two factors that could cause a difference in oxygen release between your biceps and
quadriceps.
25. Anxiety can cause a person to hyperventilate (rapid deep breathing). This can cause a
variety of symptoms, including dizziness and fainting. What changes would you expect in
systemic arterial (i.e. blood leaving the lungs and heart to the rest of the body) O2 and
CO2 concentration and pH during an episode of hyperventilation? Breathing into a paper
bag is often suggested as a treatment for hyperventilation. Do you think this would work?
Why or why not?
26. Which compartment of the mammalian heart has the largest muscle mass? Why is
this so? What are the functions of the right atrium, left atrium, right ventricle, and left
ventricle? Where are valves located? Where are they absent? What is their purpose?
27. Explain the differences in wall structures of arteries, capillaries, and veins. Why do
we see these differences?
28. Explain the forces that move material out of and into blood capillaries. Why does
fluid tend to leave capillaries at their proximal half and entire capillaries at their distal
half? Explain the relationship between blood pressure and colloidal osmotic pressure.
29. How does fluid get back to the heart? Describe the relative blood volume, blood
pressure, and blood velocity in arteries, capillaries, and veins. Why is blood flow (blood
velocity) slow in the capillaries?
30. How does the potential capacity of capillary blood volume compare with your actual
blood volume?
31. What are the major differences between an open and a closed circulatory system?
What (if any) are the advantages of a closed circulatory system? Do open and closed
circulatory systems show a conserved pattern of evolution? In other words, have they
only evolved once (conserved) or have they evolved multiple times? What is the
evidence for this?
32. Describe the major transitions between 2-, 3- and 4- chambered hearts in the
circulatory system and the distribution of blood to the lung, peripheral tissues, gills (in
the case of teleosts & lungfish) and heart among the following groups: teleost fish,
lungfish, amphibians, mammals, birds, and reptiles. How many times has a 4-chambered
heart evolved? What is the primary advantage of a 4-chambered heart? Be able to draw
out the general diagram of a 2-, 3- and 4chambered heart and the blood flow to the gills, lungs, and tissues.
33. What percentage of capillary beds is typically passing blood at any given time in
your body? What would be the physiological effect of all capillary beds becoming
suddenly active (open). What does this tell you about the dynamics of energy needs of
your tissues?
34. Explain what controls the firing of the heart? Why is the mammalian heart called
myogenic whereas insects hearts are neurogenic? What is the purpose of the SA node?
What is the purpose of the AV node and how does it accomplish its task? Discuss the 3
major ways that blood pressure can be regulated.
35. What are some possible advantages of a double circulation (i.e. a 4 chamber heart)
over a single-circuit circulation (i.e. a 2 chamber heart) ?
36. What would happen if you heart did not have an AV node?
37. After a heart transplant, there is no direct connection between the nervous system and
the heart. However, the cardiac output of patients with heart transplants can vary in
response to changes in metabolic demand (such as during exercise). How could this be
possible? Would you expect this regulation to be as efficient as in a patient with an intact
heart?
38. What are the major factors involved in the evolution of closed circulatory systems?
Do all animals fit with this general rule?
39. What is the difference between a neurogenic heart and a myogenic heart?
40. After a heart transplant, there is no direct connection between the nervous system
and the heart. However, the cardiac output of patients with heart transplants can vary in
response to changes in metabolic demand (such as during exercise). How could this be
possible? Would you expect this regulation to be as efficient as in a patient with an intact
heart?
41. The Mysterious Human Heart - Endlessly Beating - What is the LVAD and how does
it work? How does the LVAD connect to the heart? Why do people with ventricle assist
devices need blood transfusions? Why does this make subsequent heart transplants more
difficult? Why did the surgical team remove all of Bob’s blood and replace it with ice
water? What were the effects of lowering Bob’s body temperature to 64F? What would
have happened if they had not done this?
42. The Mysterious Human Heart - Spark of Life - What is long Q-T syndrome? How
does it increase the chances of death? How was Kevin’s long Q-T syndrome treated?
What is the difference between a pacemaker and a defibrillator? What does each do?
What caused Susan’s fast heart rate and how did they treat it? What do the P, Q-R-S, and
T peaks on an ECG correspond to? What is Chagas disease? How is it spread? What
does it do to the heart and how does this affect the electrical firing/signaling of the heart?
How do they treat this condition?
Questions From Lab
43. What is the Reverse Bohr Effect? What types of animals would you expect to
possess a Reverse Bohr Effect? Under what conditions does a “Normal Bohr Effect”
work? Be able to draw both the graphs for both the Reverse Bohr Effect and the Normal
Bohr Effect.
44. What is p50? What is it a measure of? Fish that live in very warm water have lower
values of p50 than fish that live in very cold water. Why might this be? Which do you
think would be more active – a fish with a low value of p50 or a fish with a high value of
p50?
45. The time needed for a substance to diffuse across a distance is given by the
following:
t=x2/4D
where x is the distance and D is the diffusion coefficient.
How can we use this equation above to explain the fact that most animals that rely solely
on diffusion for respiration are very thin (a few millimeters) and flat and have most of
their cells close to the surface of their bodies?
We will have both multiple choice and short answer questions on the exam. Last
year, we only had multiple choice. Below are some of the multiple choice questions.
4. Where are the valves located in the heart?
a) between the anterior vena cava and right atrium
b) between the atria and the ventricles
c) between the pulmonary veins and the left atrium
d) between the aorta and left atrium
Below is my drawing of two curves showing the relationship between concentration of
oxygen and percent oxygen saturation of hemoglobin that occurs with the Bohr shift.
9. What is happening at points A and B?
a) A – blood is leaving the tissues; B – blood in entering the tissues.
b) A- blood is leaving the lungs; B – blood is entering the lungs.
c) A- blood is leaving the lungs; B- blood is entering the tissues.
d) A- blood is entering the lungs; B- blood is leaving the tissues.
10. What is happening at points C and D?
a) C- blood is entering the lungs; D – blood is leaving the lungs.
b) C-blood is leaving the lungs; D- blood is leaving the tissues.
c) C-blood is entering the tissues; D- blood is entering the lungs.
d) C-blood is leaving the tissues; D- blood is entering the lungs.
11. Which statements best describe curves 1 and 2?
a) Curve 1 = loading curve. Curve 2 = unloading curve. pHcurve 1< pHcurve 2
b) Curve 1 = unloading curve. Curve 2 = loading curve. pHcurve 1< pHcurve 2
c) a) Curve 1 = loading curve. Curve 2 = unloading curve. pHcurve 1> pHcurve 2
d) Curve 1 = unloading curve. Curve 2 = loading curve. pHcurve 1> pHcurve 2
Below is the chemical reaction that takes place when CO2 dissolves in to water. I have
labeled the two reactions as 1 and 2.
(1)
(2)
CO2 + H2O ↔ H2CO3 ↔ H+ + HCO312. Under natural circumstances, which parts of this reaction are slow and which are
fast?
a) Reaction 1 is fast, and reaction 2 is slow.
b) Both reactions 1 and 2 are slow.
c) Both reactions 1 and 2 are fast.
d) Reaction 1 is slow, and reaction 2 is fast.
13. Carbonic anhydrase (CA) is very abundant in red blood cells (RBCs). What is the
role of carbonic anhydrase in gas exchange at the tissues?
a) creates HCO3b) creates HCO3c) creates HCO3d) creates HCO3-
in the RBC which causes most CO2 to diffuse into the plasma.
in the RBC which causes most of CO2 to diffuse into the RBC.
in the plasma which causes most CO2 to diffuse into the plasma.
in the RBC which causes most CO2 to diffuse into the tissues.
14. Carbonic anhydrase is also found in the endothelial cells of the capillaries in the
lungs. What is its role at this location?
a) CA converts bicarbonate to CO2 in the blood plasma.
b) CA helps convert CO2 into O2 at the lungs.
c) CA converts CO2 to bicarbonate in the blood plasma.
d) CA stabilizes carbonic acid.
15. Birds extract more O2 from the air than do mammals. Why is this?
a) Birds have a counter current mechanism.
b) Birds have tidal respiration.
c) Birds extract O2 from air in their air sacs.
d) Birds have circular respiration.
e) B and C.
Another reaction important for gas transfer is listed below.
O2 + Hb ↔ Hb-O2 + H+
16. At the lungs, this reaction proceeds to the right. What is the importance of the
production of H+ ions?
a) shifts bicarbonate reaction to go to the left and results in CO2.
b) shifts bicarbonate reaction to go to the right and results in bicarbonate.
c) This causes hemoglobin to become unstable and releases CO2.
d) A and C.
The graph below shows the velocity of the blood through the vascular system.
arteries - capillaries - veins
17. What is the primary reason for the decrease in velocity in the capillaries?
a) The small diameter of the vessels creates a lot of friction.
b) Fluid flows out to the tissues and this decreases flow.
c) High blood pressure in the capillaries decreases flow.
d) Capillaries have a large cross-sectional area.
18. Which statement best describes blood pressure (BP) in the vessels?
a) BP is high in arteries, but low in capillaries and veins.
b) BP is high in arteries and capillaries, but low in veins.
c) BP is high in veins, but low in arteries and capillaries.
d) BP is high in arteries and veins, but low in capillaries.
19. How does blood get back to the heart?
a) High BP in veins sends blood back to heart.
b) Muscle contractions along veins sends blood back to heart.
c) Negative BP in veins sends blood back to heart.
d) A and B.
The diagram below depicts the movement of fluid in and out of capillary as blood flows
through it.
20. What is happening at point A?
a) Fluid is moving into the capillary due to low blood pressure.
b) Fluid is moving out of the capillary due to high osmotic pressure.
c) Fluid is moving out of the capillary due to high blood pressure.
d) Fluid is moving into the capillary due to low osmotic pressure.
21. What is happening at point B?
a) Fluid is moving into the capillary due to high osmotic pressure.
b) Fluid is moving out of the capillary due to high blood pressure.
c) Fluid is moving into the capillary due to low blood pressure.
d) Fluid is moving out of the capillary high osmotic pressure.
22. What are the limitations for using skin as a respiratory surface?
a) only works well in air because O2 is more abundant in air than water.
b) only works well for large animals due to a high surface area to volume ratio.
c) only works for small animals due to high surface area to volume ratio.
d) only works when capillaries are a long distance from skin.
23. Which of the following are adaptations of Weddell seals that allow them to stay
underwater (and not breathe) for up to 1 hour?
a) a very large amount of blood in their bodies.
b) the ability to store large amounts of O2 in their muscles.
c) the ability to store large amounts of O2 in their liver.
d) A and B
e) B and C
The graph below shows the change in O2 content in both water and blood as water pours
over a fish’s gills.
1
[O2]
3
4
2
space along gill
24. What do points 1 and 2 represent?
a) 1 - water entering the gills, 2- water exiting the gills
b) 1 - water exiting the gills, 2-water entering the gills
c) 1 - water entering the blood, 2- water exiting the blood
d) 1 - water exiting the blood, 2-water entering the blood
25. What do points 3 and 4 represent?
a) 3 - blood entering the gills, 4- blood exiting the gills
b) 3 - blood exiting the gills, 4-blood entering the gills
c) 3 - blood entering the water, 4- blood exiting the water
d) 3 - blood exiting the water, 4-blood entering the water