Which of the following statements regarding the insect tracheal system is/are correct? Select True or False for each statement. T/F Tracheae dilate and constrict during flight or other types of movement, functioning as a 'breathing' mechanism. T/F Spiracles open into the body cavity, allowing direct contact between the air and hemolymph. T/F Tracheae carry oxygen to alveoli; here the oxygen diffuses into the hemolymph to be delivered to tissues. T/F Spiracles can close to minimize water loss.

Identify at least two advantages of breathing air instead of water.

Which of the following promotes oxygen release from hemoglobin? a. a decrease in temperature b. an increase in O2 level c. a decrease in pH d. a decrease in carbonic anhydrase activity

Describe the disadvantages of an open circulatory system relative to a closed circulatory system.

Explain how each parameter in Fick's law of diffusion is reflected in the structure of the mammalian lung.

Frog lungs have a smaller surface area for gas exchange than mammalian lungs. How do frogs compensate for this difference? a. Frog tissue absorbs more oxygen from the blood than mammalian tissue does. b. Frogs breathe more quickly than mammals. c. Frogs also obtain oxygen via diffusion across the skin. d. Frog lung tissue has a greater density of capillary beds than mammalian lung tissue.

Carp are fishes that thrive in stagnant-water habitats with low oxygen partial pressure. Compared with the hemoglobin of many other fish species, carp hemoglobin has an extremely high affinity for O2. Draw an oxygen–hemoglobin equilibrium curve showing separate lines for carp and a fish that lives in water with a higher oxygen partial pressure. Explain why they differ.

Explain why a person who survives a myocardial infarction might need to have an artificial pacemaker implanted.

Predict how Antarctic icefish can transport enough oxygen in their blood to meet their needs even though they lack hemoglobin.

Why did separate systemic and pulmonary circulations evolve in species that have the high-pressure circulatory system required for rapid movement of blood?

During exercise, the cardiovascular system must supply muscles with large amounts of oxygen and fuel and get rid of a lot of wastes. How do the cardiovascular systems of athletes respond to prolonged exercise? During athletic training, the oxygen–hemoglobin dissociation curve a. shifts to the right, unloading more oxygen to tissues. b. shifts to the right, unloading less oxygen to tissues. c. shifts to the left, unloading more oxygen to tissues. d. shifts to the left, unloading less oxygen to tissues.

During exercise, the cardiovascular system must supply muscles with large amounts of oxygen and fuel and get rid of a lot of wastes. How do the cardiovascular systems of athletes respond to prolonged exercise? When athletes exercise, what is the primary physiological variable responsible for their sustained increase in ventilation rate? a. decreased blood PO2 b. increased blood PCO2 c. increased blood pH d. increased body temperature

During exercise, the cardiovascular system must supply muscles with large amounts of oxygen and fuel and get rid of a lot of wastes. How do the cardiovascular systems of athletes respond to prolonged exercise? Researchers used echocardiography, a sonogram of the heart, to estimate the mass of the left ventricle in current athletes, non-athletes, and ex-athletes. The data are graphed below (*** means P<0.001, and the P value comparing non-athletes and ex-athletes is >0.05). What conclusion can be drawn from the graph?

During exercise, the cardiovascular system must supply muscles with large amounts of oxygen and fuel and get rid of a lot of wastes. How do the cardiovascular systems of athletes respond to prolonged exercise? Explain the advantage of the observed difference between current athletes and non-athletes in the graph shown here.

During exercise, the cardiovascular system must supply muscles with large amounts of oxygen and fuel and get rid of a lot of wastes. How do the cardiovascular systems of athletes respond to prolonged exercise? Researchers have also observed that athletes and non-athletes have the same mean resting cardiac output, even though athletes have a far lower resting heart rate. How is this possible?

During exercise, the cardiovascular system must supply muscles with large amounts of oxygen and fuel and get rid of a lot of wastes. How do the cardiovascular systems of athletes respond to prolonged exercise? Athletes are not the only people with enlarged hearts. Many patients with cardiovascular disease also have enlarged hearts. Suggest a cause of this enlargement.