Chapter 39 BIOS

Which of the following statements is false? Ventilation increases the concentration of oxygen in the air on the outside of the respiratory surface. Circulation requires a pump to generate pressure to drive flow, whereas ventilation does not. Larger, more complex animals rely on bulk flow and diffusion to deliver oxygen to their cells, whereas some smaller, simpler animals rely on diffusion alone. The same amount of oxygen enters the blood through diffusion as is transported by circulation. Oxygen and carbon dioxide both move across the respiratory surface by diffusion.

Circulation requires a pump to generate pressure to drive flow, whereas ventilation does not.

Which of the following statements about bird respiration is false? Bird lungs receive fresh air during both inhalation and exhalation. The unidirectional flow of air through a bird's lungs maintains a larger concentration gradient for diffusion than can be obtained through tidal breathing. Air flowing through the air channels in the lungs moves in a tidal fashion. It takes two ventilation cycles for a single breath of air to move through a bird's respiratory system. Oxygen is exchanged between the air and the bloodstream in the lungs, but not in the air sac

Correct: Air flowing through the air channels in the lungs moves in a tidal fashion.

What is the advantage for birds and mammals of having a four-chambered heart? It allows for complete separation of systemic and pulmonary circulation. It allows for complete separation of oxygenated and deoxygenated blood. It allows for different pressures in the systemic and pulmonary circuits. It allows for increased supply of oxygenated blood to active tissues. All of these choices are correct.

Correct: All of these choices are correct.

Which of the following statements is true regarding CO2 in the mammalian bloodstream? Like oxygen, CO2 is transported through the mammalian bloodstream via hemoglobin; however, CO2 binds to hemoglobin at β subunits rather than heme groups. Unlike oxygen, CO2 is transported through the mammalian bloodstream by myoglobin. All CO2 is transported through the mammalian bloodstream as a dissolved gas, and is carried directly in the plasma. CO2 is mainly transported through the mammalian bloodstream in the form of bicarbonate ions or carbonic acid. In the mammalian bloodstream, CO2 is much less soluble than O2.

Correct: CO₂ is mainly transported through the mammalian bloodstream in the form of bicarbonate ions or carbonic acid.

A researcher has sectioned a mouse embryo, and has noticed that certain muscle components (especially myosin) aggregate around the early-stage cartilage of the ribs. Which of the following is true of these presumptive muscles? Since they associate with the ribs, these muscles are likely components of the diaphragm. These muscles likely only serve a supportive role for the ribs, and will play no role in breathing. Since they associate with the ribs, these muscles are likely developing intercostal muscles. These muscles (when they are fully developed) will help to regulate the volume of the thoracic cavity. Since they associate with the ribs, these muscles are likely developing intercostal muscles. As a result, these muscles (when fully developed) will help to regulate the volume of the mouse's thoracic cavity.

Correct: Since they associate with the ribs, these muscles are likely developing intercostal muscles. As a result, these muscles (when fully developed) will help to regulate the volume of the mouse's thoracic cavity.

Which of the following statements is false? Blood pressure in the pulmonary circulation is lower than blood pressure in the systemic circulation. The walls of the right ventricle are thicker than the walls of the left ventricle. The systemic blood pressure of a bird is much higher than that of a fish. The left ventricle pumps oxygenated blood, whereas the right ventricle pumps deoxygenated blood.

Correct: The walls of the right ventricle are thicker than the walls of the left ventricle.

Which of the following organisms would be able to extract the greatest percentage of oxygen from their respiratory medium? sparrows humans salmon blue whales seagulls

Correct: salmon

Which of the following statements is false? Chemoreceptors involved in the homeostatic control of breathing are located in the brainstem and the carotid and aortic bodies. Breathing is controlled by both voluntary and involuntary mechanisms. Decreasing levels of oxygen in the blood are detected by chemoreceptors in the brainstem. As an organism's activity level increases, the level of CO2 in the blood will increase and stimulate faster or stronger breathing. Stronger or more frequent contraction of respiratory muscles helps to remove excess CO2 from the blood.

Decreasing levels of oxygen in the blood are detected by chemoreceptors in the brainstem.

A scientist is evaluating the hemoglobin in mountain goats compared to the hemoglobin in normal barnyard goats. How will the hemoglobin in these two goat species compare?

Given that mountain goats tend to live at higher altitudes, these goats will have hemoglobin with a greater oxygen-binding affinity compared to the hemoglobin of barnyard goats.

Which of the following statements about hemoglobin is false? The similarity of vertebrate and invertebrate hemoglobins suggests that a shared form of hemoglobin evolved in a common ancestor of these lineages. Hemoglobin increases the amount of oxygen in vertebrate blood one hundredfold. Hemoglobin is only found within blood cells in animal bodies. Some plants use hemoglobin to bind oxygen in order to keep cellular oxygen concentrations low.

Hemoglobin is only found within blood cells in animal bodies.

A researcher is studying a strain of mice that only incorporate 50 percent of the necessary iron into their hemoglobin molecules. Which of the following statements is likely true regarding these mutant mice?

The hemoglobin in these mutant mice will be able to bind half the number of oxygen molecules compared to the hemoglobin of normal or wild-type mice.

A researcher is culturing cells in an incubator where the gas levels are carefully regulated. If the researcher observes that the pO2 in the incubator is 200 mmHg, what can the researcher deduce about the pO2 of her cells?

The pO2 of her cells is less than or equal to 200 mmHg.

At any given point along the length of the gill lamella, how does the pO2 of the blood flowing through the blood vessels in the lamella compare to the pO2of the water flowing over the gill lamella?

The pO2 of the blood is lower than the pO2 of the water.

If the partial pressure of oxygen outside of a cell is 100 mmHg and the partial pressure of oxygen inside of a cell is 25 mmHg, which of the following statements is correct?

There will be a net movement of oxygen from outside the cell to inside the cell.

A man has just learned that he has a blockage in one of his arteries. Which of the following statements is true regarding this blockage?

This blockage will likely increase the resistance to flow in his circulatory system, and as a result will decrease the rate of blood flow.

Which of the following blood vessels play an important role in controlling blood flow to different regions of the body through the contraction and relaxation of smooth muscles in their walls?

arterioles

The muscles of which of the following organisms would likely have the lowest myoglobin concentration? blue whale seal sperm whale human dolphin

human

Which of the following would increase the rate of oxygen diffusion from the air into the body cells of a flatworm?

increasing the body surface area

Which of the following describes the correct path of air through the human respiratory system?

larynx, trachea, bronchi, bronchioles, alveoli

At the venous end of a capillary, the blood pressure is _____ the osmotic pressure and fluid _____ the blood vessel.

lower than; moves into

Which of the following occurs during exhalation?

none

In which of the following heart chambers would deoxygenated blood be found?

right atrium, right ventricle

A rightward shift in the oxygen dissociation curve means that:

the affinity of hemoglobin for O2 has decreased

A medical student is dissecting a cadaver. She notices certain vessels that do not appear to be involved in blood transport. These may be components of the lymphatic system.

true