One of the many mutant opponents that the movie monster

How is the flow of hemolymph through an open circulatory system similar to the flow of water through an outdoor fountain?

Three-chambered hearts with incomplete septa were once viewed as being less adapted to circulatory function than mammalian hearts. What advantage of such hearts did this viewpoint overlook?

The heart of a normally developing human fetus has a hole between the left and right atria. In some cases, this hole does not close completely before birth. If the hole werent surgically corrected, how would it affect the O2 content of the blood entering the systemic circuit?

How does the flow of a fluid in a closed circulatory system differ from the movement of molecules between cells and their environment with regard to distance traveled, direction traveled, and driving force?

Explain why blood in the pulmonary veins has a higher O2 concentration than blood in the venae cavae, which are also veins

Why is it important that the AV node delay the electrical impulse moving from the SA node and the atria to the ventricles?

After exercising regularly for several months, you find that your resting heart rate has decreased. What other change in the function of your heart at rest would you expect to find? Explain.

What changes in cardiac function might you expect after surgical replacement of a defective heart valve?

What is the primary cause of the low velocity of blood flow through capillaries?

What short-term changes in cardiovascular function might best enable skeletal muscles to help an animal escape from a dangerous situation?

If you had additional hearts distributed throughout your body, what would be one likely advantage and one likely disadvantage?

If you placed your forearm on your head, how, if at all, would the blood pressure in that arm change? Explain.

Explain why a physician might order a white cell count for a patient with symptoms of an infection

Clots in arteries can cause heart attacks and strokes. Why, then, does it make sense to treat hemophiliacs by introducing clotting factors into their blood?

Nitroglycerin (the key ingredient in dynamite) is sometimes prescribed for heart disease patients. Within the body, the nitroglycerin is converted to nitric oxide. Why would you expect nitroglycerin to relieve chest pain in these patients?

The allele that encodes HbS is codominant with the allele encoding normal hemoglobin (Hb) (see Concept 14.4, pp. 277278). What can you deduce about the properties of Hb and HbS with regard to aggregate formation and sickling?

How do stem cells from the bone marrow of an adult differ from embryonic stem cells (see Concept 20.3, p. 415416)?

In the absence of infection, what percentage of cells in human blood are leukocytes?

Why is the position of lung tissues within the body an advantage for terrestrial animals?

After a heavy rain, earthworms come to the surface. How would you explain this behavior in terms of an earthworms requirements for gas exchange?

Describe how countercurrent exchange can facilitate both thermoregulation (see Concept 40.3, p. 865) and respiration.

Why does altitude have almost no effect on an animals ability to rid itself of CO2 through gas exchange?

How does an increase in the CO2 concentration in the blood affect the pH of cerebrospinal fluid?

A drop in blood pH causes an increase in heart rate. What is the function of this control mechanism?

If an injury tore a small hole in the membranes surrounding your lungs, what effect on lung function would you expect?

How does tidal volume differ from the volume of fresh air that enters the body during inspiration?

What determines whether O2 and CO2 diffuse into or out of the capillaries in the tissues and near the alveoli? Explain

How does the Bohr shift help deliver O2 to very active tissues?

A doctor might give bicarbonate (HCO3 ) to a patient who is breathing very rapidly. What assumption is the doctor making about the blood chemistry of the patient?

In what way is the role of a respiratory pigment like that of an enzyme?

Which of the following respiratory systems is not closely associated with a blood supply? a. the lungs of a vertebrate b. the gills of a fish c. the tracheal system of an insect d. the skin of an earthworm e. the parapodia of a polychaete worm

Blood returning to the mammalian heart in a pulmonary vein drains first into the a. vena cava. d. left ventricle. b. left atrium. e. right ventricle. c. right atrium.

Pulse is a direct measure of a. blood pressure. d. heart rate. b. stroke volume. e. breathing rate. c. cardiac output.

When you hold your breath, which of the following blood gas changes first leads to the urge to breathe? a. rising O2 d. falling CO2 b. falling O2 e. rising CO2 and falling O2 c. rising CO2

One feature that amphibians and humans have in common is a. the number of heart chambers. b. the type of gas exchange tissues. c. a complete separation of circuits for circulation. d. the number of circuits for circulation. e. a low blood pressure in the systemic circuit.

If a molecule of CO2 released into the blood in your left toe is exhaled from your nose, it must pass through all of the following except a. the pulmonary vein. d. the right atrium. b. an alveolus. e. the right ventricle. c. the trachea

Compared with the interstitial fluid that bathes active muscle cells, blood reaching these cells in arteries has a a. higher PO2 . b. higher PCO2 . c. greater bicarbonate concentration. d. lower pH. e. lower osmotic pressure

Which of the following reactions prevails in red blood cells traveling through alveolar capillaries? (Hb hemoglobin) a. Hb 4 O2 S Hb(O2)4 d. H2CO3 S HHCO3 b. Hb(O2)4 S Hb 4 O2 e. Hb 4 CO2 S Hb(CO2)4 c. CO2 H2O S H2CO3

Plot blood pressure against time for one cardiac cycle in humans, drawing separate lines for the pressure in the aorta, the left ventricle, and the right ventricle. Below the time axis, add a vertical arrow pointing to the time when you expect a peak in atrial blood pressure.

One of the many mutant opponents that the movie monster Godzilla contends with is Mothra, a giant mothlike creature with a wingspan of several dozen meters. Science fiction creatures like these can be critiqued on the grounds of biomechanical and physiological principles. What problems of respiration and gas exchange would Mothra face? The largest insects that have ever lived are Paleozoic dragonflies with half-meter wingspans. Why do you think truly giant insects are improbable?

The hemoglobin of a human fetus differs from adult hemoglobin. Compare the dissociation curves of the two hemoglobins in the graph at right. Propose a hypothesis to explain the benefit of this difference between these two hemoglobins.

Hundreds of studies have linked smoking with cardiovascular and lung disease. According to most health authorities, smoking is the leading cause of preventable, premature death in the United States. Antismoking groups have proposed that cigarette advertising in all media be banned entirely. What are some arguments in favor of a total ban on cigarette advertising? What are arguments in opposition? Do you favor or oppose such a ban? Defend your position.

Some athletes prepare for competition at sea level by sleeping in a tent in which PO2 is kept artificially low. When climbing very high peaks, some mountaineers breathe from bottles of pure O2. In a short essay (100150 words), relate these behaviors to the mechanism of O2 transport in the human body and to our physiological interactions with our gaseous environment.