AP Biology : Understanding Other Vascular Physiology

Study concepts, example questions & explanations for AP Biology

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Example Questions

Example Question #1 : Understanding Other Vascular Physiology

Which of the following helps cool the body temperature?

Possible Answers:

Peripheral vasodilation

None of these

Peripheral vasoconstriction

Hyperventilation

Shivering

Correct answer:

Peripheral vasodilation

Explanation:

When the body temperature is too high, peripheral vasodilation can help exchange heat from the body to the environment. Warm blood from the center of the body is pumped to the extremities, which have a high surface area. The surface area is used to allow the heat from the blood to dissipate before it returns to the center of the body.

Peripheral vasoconstriction and shivering help increase the body temperature. Hyperventilation have no noticeable effect on body temperature.

Example Question #2 : Understanding Other Vascular Physiology

The exchange of oxygen and carbon dioxide occurs in which of the following structures?

Possible Answers:

Veins

Lymph ducts

Capillaries

Arteries

Sinusoids

Correct answer:

Capillaries

Explanation:

Capillaries are minute blood vessels that connect the arterial and venous systems. The walls of these vessels are extremely thin, allowing easy diffusion of gases, nutrients, and waste particles between the capillary and adjacent cells. Oxygen diffuses into cells from the capillary, and carbon dioxide diffuses into the capillary from the cells.

Example Question #3 : Understanding Other Vascular Physiology

Which blood vessel type can be constricted in order to reroute blood?

Possible Answers:

Arteriole

Artery

Capillary

Venule

Correct answer:

Arteriole

Explanation:

Vasoconstriction is a function of the smooth muscle that surrounds the vasculature. In order to reroute blood, the vessel needs to have a substantial amount of smooth muscle.

Arterioles have a relatively small diameter and a relatively large amount of smooth muscle. When contracted, this smooth muscle can obstruct the arteriole and route blood away from connected capillary beds. Capillaries do not have smooth muscle linings, and cannot constrict or reroute blood on their own. Arteries have a relatively large diameter; contraction of the surrounding smooth muscle can affect blood pressure, but will rarely be capable of rerouting the blood flow.

Example Question #4 : Understanding Other Vascular Physiology

What prevents backflow of blood in veins?

Possible Answers:

Veins contain cilia which push the blood forward

Veins contain a series of one-way valves that allow blood to only flow in one direction

Nothing; blood often flows backward in veins

Blood pressure by itself is enough to keep blood flowing in a single direction

Correct answer:

Veins contain a series of one-way valves that allow blood to only flow in one direction

Explanation:

Veins contain a series of one way valves that prevent blood from flowing backwards. This is particularly important in larger veins in the legs that are further below the heart, and must oppose gravity to get blood back to the heart. Almost all of the blood pressure produced by the heart is lost along capillaries, thus the blood pressure in the veins is almost zero. Blood is "squished up" a little at a time due to the contraction of the skeletal muscles around veins and the presence unidirectional valves.

Example Question #5 : Understanding Other Vascular Physiology

Oxygen-poor blood returns to the heart via which structure?

Possible Answers:

Left atrium

Pulmonary vein

Left ventricle

Pulmonary artery

Vena cava

Correct answer:

Vena cava

Explanation:

The venae cavae are the largest veins in the body. They return deoxygenated blood to the heart. The pulmonary veins bring oxygenated blood from the lungs to the left atrium. The pulmonary arteries bring deoxygenated blood from the right ventricle to the lungs to become oxygenated. The left ventricle hold oxygen-rich blood, and pumps it to the rest of the body. The left atrium is where freshly oxygenated blood is received via the pulmonary veins.

Example Question #6 : Understanding Other Vascular Physiology

The stable pH of human blood is closest to which of the following?

Possible Answers:

2-7

7.5

6.5

7-10

Correct answer:

7.5

Explanation:

The stable pH of blood is around 7.5 and is maintained by buffers, especially carbon dioxide/bicarbonate. Note that the blood pH is very tightly regulated and is adjusted by the respiratory and urinary systems.

Example Question #7 : Understanding Other Vascular Physiology

Blood with the highest oxygen content would be found where?

Possible Answers:

Pulmonary arteries

Aorta

Pulmonary veins

Coronary artery

Vena cava

Correct answer:

Pulmonary veins

Explanation:

The correct answer is pulmonary veins. The pulmonary veins transfer the newly oxygenated blood towards the heart. Blood in these veins is highly concentrated with oxygen unlike any of the other locations mentioned. The pulmonary arteries bring oxygen-poor blood towards the lungs to be oxygenized.

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