Chapter 37 Learning Curve

A researcher has sectioned a mouse embryo and notices that certain muscle components (especially myosin) aggregate around the early-stage cartilage of the ribs. Which of the statements is true of these presumptive muscles?

Because they associate with the ribs, these muscles are likely developing intercostal muscles.

Which of the statements is true regarding CO2 in the mammalian bloodstream?

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

A researcher has introduced molecules of human myoglobin and hemoglobin into a solution containing oxygen. Which of the statements is true of human hemoglobin and myoglobin?

Compared to human hemoglobin, human myoglobin will likely bind to oxygen molecules more quickly when introduced into the oxygen-containing solution.

All of the statements are true except:

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

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.

What is the main benefit of having hemoglobin in the blood?

It increases the amount of oxygen that can be carried in the blood.

If heart rate decreases 30% followed by stroke volume decreasing 10%, then what effect do these decreases have on the total cardiac output?

The cardiac output decreases by 37%.

A researcher is studying a strain of mice that only incorporates 50% of the necessary iron into their hemoglobin molecules. Which of the 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 that require oxygen to live 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 pO2 of the water flowing over the gill lamella?

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

Which of the statements about bird respiration is true?

The unidirectional flow of air through a bird's lungs maintains a larger concentration gradient for diffusion than can be obtained through tidal breathing.

A man has just learned that he has a blockage in one of his arteries. Which of the 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.

The pacemaker of the mammalian heart is:

a group of specialized cardiac muscle cells that initiate the heartbeat.

Which of the factors affects the rate of diffusion of a substance?

concentration gradient

Cardiac output equals:

heart rate times stroke volume.

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

increasing the surface area of the body

What percentage of oxygen in the air is typically extracted by the mammalian lung when an animal is resting?

less than 25%

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

lower than; moves into

Insects possess _____ circulatory systems, circulatory systems in which hemolymph completely "bathes" the organs and is not typically contained in distinct arteries or veins.

open

What is the function of surfactant in the mammalian respiratory system?

reduction of surface tension in the fluid covering the alveoli

During heavy exercise, blood pH will decrease. This will result in a shift to the ________ of the hemoglobin dissociation curve shown.

right

Which of these chemicals will not pass through the phospholipid bilayer of a membrane?

sodium ions

A shift to the right in the hemoglobin dissociation curve means that:

the affinity of hemoglobin for O2 has decreased.

Why do cells in the airways of the lungs produce mucus?

to trap pathogens and guard against infection

As you read this sentence, you have breathed in and out. What you have just experienced is referred to as "gas exchange," where you have taken oxygen into your lungs and expelled carbon dioxide into the environment.

true

Medical students are dissecting a cadaver. They notice certain vessels that do not appear to be involved in blood transport. These may be components of the lymphatic system.

true