A significant increase in the amount of interstitial fluid surrounding the capillary beds of a human's lungs will cause

a decrease in the amount of oxygen moving from the lungs into the blood

When the air in a testing chamber is specially mixed so that its oxygen content is 10% and its overall air pressure is 400 mm Hg, then PO₂ is

40 mm Hg

The sun shining on a tidal pool during a hot day heats the water. As some water evaporates, the pool becomes saltier, causing

a decrease in its oxygen content

Sponges, cnidarians, and flatworms lack a specialized gas exchange surface because

nearly all of their cells are in direct contact with the external environment

In mammals, most gas exchange between the atmosphere and the pulmonary blood occurs in the

alveoli

Gas exchange is more difficult for aquatic animals with gills than for terrestrial animals with lungs because

water contains much less O₂ than air per unit volume

Countercurrent exchange is evident in

the flow of water across the gills of a fish and that of blood within those gills.

Countercurrent exchange in the fish gill helps to maximize

diffusion

Air-breathing insects carry out gas exchange

across the finest branches of the trachea and cell membranes

An oil-water mixture works as an insecticidal spray against mosquitoes and other insects because it

blocks the openings into the tracheal system

Atmospheric pressure at sea level is equal to a column of 760 mm Hg. Oxygen makes up 21% of the atmosphere by volume. The partial pressure of oxygen (PO₂) in such conditions is

160 mm Hg

Some human infants, especially those born prematurely, suffer serious respiratory failure because of

lung collapse due to inadequate production of surfactant

At an atmospheric pressure of 870 mm Hg of 21% oxygen, the partial pressure of oxygen is

182 mm Hg

At sea level, atmospheric pressure is 760 mm Hg. Oxygen gas is approximately 21% of the total gases in the atmosphere, so the approximate partial pressure of oxygen is

160.0 mm Hg

At the summit of a high mountain, the atmospheric pressure is 380 mm Hg. If the atmosphere is still composed of 21% oxygen, then the partial pressure of oxygen at this altitude is

80 mm Hg

Of the following choices, impairment of a mammal's breathing cycle is most likely following neural damage in

the medulla oblongata and the pons

Air rushes into the lungs of humans during inhalation because

the rib muscles and diaphragm contract, increasing the lung volume

The exhalation of air from human lungs is driven by

a decrease in the volume of the thoracic cavity

During most daily activities, the human respiration rate is most closely linked to the blood levels of

carbon dioxide

Breathing is usually regulated by

CO₂ and O₂ concentration and pH-level sensors

Carbon dioxide levels in the blood and cerebrospinal fluid affect their pH. This enables the organism to sense a disturbance in gas levels as

the medulla oblongata, which is in contact with cerebrospinal fluid, monitors pH and uses this measure to control breathing

To become bound to hemoglobin for transport in a mammal, atmospheric molecules of oxygen must cross

five membranes–in and out of the cell lining the lung, in and out of the endothelial cell lining an alveolar capillary, and into the red blood cell–to bind with hemoglobin.

An increase from pH 7.2 to pH 7.4 around hemoglobin causes

an increase in the affinity of hemoglobin to bind oxygen molecules

An "internal reservoir" of oxygen in rested muscle is found in oxygen molecules bound to

myoglobin

Hemoglobin and hemocyanin

both transport oxygen

The Bohr shift on the oxygen-hemoglobin dissociation curve is produced by changes in

pH

Most of the carbon dioxide produced by humans is

converted to bicarbonate ions by an enzyme in red blood cells

Hydrogen ions produced within human red blood cells are prevented from significantly lowering plasma pH because they bind to

hemoglobin

The hemocyanin of arthropods and molluscs differs from the hemoglobin of mammals in that

hemocyanin has protein coupled to copper rather than iron

In an animal species known for endurance running rather than fast sprinting, you would expect to find

a much higher rate of oxygen consumption for its size.

The epiglottis of a human covers the glottis when he or she is

swallowing