Practice questions for the final exam

The final exam will be made up of two parts:

1.  A third midterm, similar to the other midterms, just on material covered since the second midterm (i.e., circulatory systems, respiratory systems, water and ion balance and kidneys).

AND

2.  A proper final exam which will draw together ideas from different parts of the course (the last lecture will be a review, which will highlight the connections between different parts of the course).

In other words the final exam WILL be cumulative and cover material from throughout the course, but there will be a focus on (1) material covered since the second midterm and (2) connections between different parts of the course.

The final exam will be approximately twice as long as each midterm, and you will have 3 hours in which to complete it.

The practice questions below are from Moyes and Schulte (answers and distribution of points are by me). The number of points that a question is worth will give you an indication of how much detail is required. Note that the number of points in my sample answers are often more than the question is worth, i.e., you would not have to get every point in my answer in order to get full marks.

At the end of each chapter in Moyes and Schulte, there are “Review questions”, “Synthesis questions” and “Quantitative questions”. The midterms and final will be about half “Review questions” and about half “Synthesis questions”, with NO questions that require a calculator.

The final questions will not necessarily be from Moyes and Schulte.

I will not give you feedback on your practice answers. Please compare answers with colleagues in the course.

Example of question that would be on second part of final exam, i.e., that draws together ideas from different parts of the course

Describe how the arrangement of the thick and thin filaments in the sarcomeres of heart muscle increases stroke volume in response to increased end-diastolic volume. Make sure that you define stroke volume and end-diastolic volume in your answer (4 points).

• Stroke volume: amount of blood that the heart pumps with each beat; end-diastolic volume: volume of blood in ventricle at end of heart filling/relaxation (each definition worth half a mark)
• If the arrangement is too cramped and actin filaments from different sides (Z disks) overlap (or they can say too much overlap between actin and myosin/ thick and thin filaments), that gets in the way of efficient cross bridge formation between myosin and actin, and in the extreme case, myosin will bump into the Z disk- no contraction possible. (a figure would help)
• At rest, the sarcomeres in the heart are a bit shorter than optimum (too much overlap between actin and myosin)
• When the animal is exercising, the volume of blood returning to the heart increases and so the muscle stretches – this stretches the sarcomere so that there is the amount of overlap between actin and myosin is optimum, which increases the ability of the heart to produce a strong contraction when it is really needed.
• Called the Frank-Starling effect

Review questions

Chapter 8, Moyes and Schulte, 2^nd edition

6. Why is the lengthy refractory period of a contractile cardiomyocyte important for the function of the mammalian heart?

7. Define heart rate, stroke volume, and cardiac output. Explain how changes in heart rate or stroke volume affect cardiac output.

8. What is the Frank-Starling effect? Explain its significance in cardiovascular physiology.

11. Describe the mechanisms that control the radius of the arterioles.

12. Outline some of the functions of the lymphatic system.

13. What is the importance of the skeletal muscle and respiratory pumps?

14. Outline the baroreceptor reflex and discuss its importance.

Note: although Moyes and Schulte’s questions don’t ask much about the molecular mechanisms through which the nervous systems affect the heart, you should still know this.

Chapter 9, Moyes and Schulte, 2^nd edition

1. Why is diffusion an inefficient respiratory strategy for organisms that are more than a few millimeters thick?

2. Compare and contrast the lungs of birds, the lungs of mammals, and the tracheal systems of insects.

3. Explain how countercurrent flow arrangements can lead to more efficient gas exchange across a respiratory surface.

5. Describe the changes in alveolar and intrapleural pressure during a single ventilatory cycle in mammals.

7. What is the significance of the red blood cell for CO2 transport in the vertebrates?

8. Outline how chemoreceptors influence ventilation in mammals.

Chapter 10, Moyes and Schulte, 2^nd edition

2. Discuss how countercurrent systems aid renal function.

4. What are the six main roles of the kidney?

6. There is a relationship between the volume of urine produced and the type of nitrogenous waste excreted by an organism. What is this relationship, and why does it occur?

8. How is energy used in ion pumping?

Synthesis questions with answers

Chapter 8, Moyes and Schulte, 2^nd edition

7. Tom suffers from high blood pressure. Which of the following might help deal with this problem?

a. A drug that stimulates alpha 1 receptors in cardiac muscle tissue.

b. A drug that blocks alpha 2 receptors in cardiac muscle tissue.

c. A drug that blocks beta receptors in cardiac muscle tissue.

d. A drug that blocks acetylcholine receptors in cardiac muscle tissue.

We didn’t get into the differences between alpha and beta receptors, so I wouldn’t ask something quite like this – specifically, I wouldn’t expect you to be able to distinguish between options b and c. However, we did go over how alpha and beta receptors are types of adrenergic receptors.

• Adrenergic receptors bind to norepinephrine and epinephrine and so receive stimulation from the sympathetic nervous system.
• Acetylcholine receptors receive stimulation from the parasympathetic nervous system.
• Stimulation from the sympathetic nervous system increases heart rate and stroke volume.
• Increases heart rate and/or stroke volume increases cardiac output, which increases blood pressure.
• Stimulation from the parasympathetic nervous system reduces heart rate.
• To reduce blood pressure, you would want to reduce cardiac output, and so reduce stimulation from the sympathetic nervous system.
• To reduce blood pressure, you would want to reduce cardiac output, and so increase stimulation from the parasympathetic nervous system.
• Only options b or c would reduce stimulation from the sympathetic n.s. (none would increase effect of parasympathetic).

A question like this would be worth 6 marks, i.e., you would not have to get every point above in order to get full marks.   

Chapter 9, Moyes and Schulte, 2^nd edition

4. In an experiment to determine the role of the air sacs in the avian lung, physiologists tied off an air sac so that gas from that air sac could no longer enter the lung. The experimenters then injected carbon monoxide into the sealed air sac. This manipulation did not decrease the oxygen saturation of hemoglobin in arterial blood. Explain why this was the case, and what this experiment demonstrates about the nature of the air sacs in birds.

In my opinion, this question is tougher than anything that is going to be on the exam.

• Carbon monoxide binds to hemoglobin with much higher affinity than does oxygen.
• Therefore, if the carbon monoxide in the sealed air sac was absorbed into the blood, it would reduce oxygen saturation of hemoglobin.
• Oxygen saturation was not reduced, therefore the carbon monoxide was not absorbed.
• This experiment demonstrates that the air sacs are not involved in gas exchange.
• Instead, the air sacs act as reservoirs for air, and when they are compressed, pump air through the parabronchi of the lungs or pump air back out of the bird.
• Gas exchange occurs in air capillaries that branch off the parabronchi.

A question like this would be worth 4 marks.

The following question is in the “quantitative” section, but I wouldn’t be looking for any specific numbers:

Synthesis questions without answers

Chapter 8, Moyes and Schulte, 2^nd edition

2. Explain the changes in blood pressure as blood flows through the mammalian circulatory system.

3. Aortic blood flow starts to increase only some time after the initiation of ventricular contraction. Similarly, aortic blood flow continues at a relatively high level well into the diastolic period. Explain why.

6. During an experiment dogs were given the drug atropine, which abolishes parasympathetic nerve transmission. What effects would you expect on the heart and why?

8. 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?

Chapter 9, Moyes and Schulte, 2^nd edition

1. 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.

5. A woman gets a disease that makes her unable to produce surfactant in her lungs. If she has a normal tidal volume, what can you say about her intrapleural pressure during inspiration?

6. What effects might you expect in a mammal whose major hemoglobin is mutated such that it lacks a Bohr effect?

7. 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.

8. In fish, there is a positive correlation between whole animal metabolic rate and the surface area of the gill. What might explain this relationship?

10. 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 biceps (arm muscles)? Describe at least two factors that could cause a difference, if any, in oxygen release between your biceps and quadriceps.

11. Imagine that you take hemoglobin molecules from both a sheep fetus and its mother. You mix equal amounts of these two hemoglobins in an aqueous solution in the presence of oxygen, at a PO2 that is not sufficient to saturate all the hemoglobin sites on the molecules you have added. Given what you know about maternal and fetal hemoglobins, where would you expect to find most of this oxygen bound? How would this compare to the amount of oxygen dissolved in your solution and not bound to hemoglobin? Why?

12. 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 O2 and CO2 concentration and pH during an episode of hyperventilation? How (i.e., by what mechanism) might this affect blood flow to the brain? Breathing into a paper bag is often suggested as a treatment for hyperventilation. Do you think that this would work? Why or why not?

Chapter 10, Moyes and Schulte, 2^nd edition

2. Discuss the integration of the respiratory and excretory systems in controlling pH balance.

5. Angiotensin-converting enzyme inhibitors (ACE inhibitors) are used to treat high blood pressure. Using a flowchart, explain why these drugs are helpful in treating hypertension.

6. The kidney of a cactus wren is less efficient at concentrating urine than are the kidneys of a kangaroo rat, yet the cactus wren produces less urine. In one or two sentences, explain this apparent contradiction.