The two-way exchange of substances between blood cells and body cells occurs only along the length of the blood vessels called:

a. capillaries.

b. arteries.

c. arterioles.

d. veins.

e. venules.

The small size of alveoli, coupled with their large numbers, provide the lungs with what critical quality for gas exchange?

a. a resistance to damage caused by pollutants

b. an affinity for oxygen and lack of affinity for carbon dioxide

c. an affinity for carbon dioxide and lack of affinity for oxygen

d. a large surface area

e. a small surface area

The movement of oxygen into the interstitial fluid from capillaries, and the movement of carbon dioxide into capillaries from the interstitial fluid is driven by:

a. ventilation.

b. hemoglobin binding.

c. the pumping of them.

d. osmotic gradients.

e. concentration gradients.

Vaccines elicit _________ on the part of the immune system by introducing ______ from a pathogenic microbe without introducing the microbe itself.

The immune system can cause trouble in three primary ways: by initiating attacks on the body’s own tissues, thus causing the conditions known as _______; by initiating the histamine-releasing overreactions known as ________; and by serving as the primary impediment to ________.

Two promising means of using components of the immune system to fight disease have begun to develop in recent years. One of them employs the cells whose natural function is to limit immune system attacks, ________; the other stimulates or suppresses the ________ that are the initial sensors of microbial infection.

The two arms of adaptive immunity are antibody-mediated immunity, which operates through the production of the proteins called _______, and cell-mediated immunity, which works through the production of cells that destroy infected _______ in the body. The central cells of antibody-mediated immunity are known as _______ cells, while the central cells of cell-mediated immunity are known as _______ cells.

An antibody is an immune system protein that can bind to a particular _______. Antibodies are seen in two forms: as receptors on the surface of _______ cells and as free-standing proteins that are _______ by these cells.

The cells of both antibody-mediated and cell-mediated immunity exist in great numbers in nodes of the body’s fluid- drainage network, the _______.

A B cell that has become activated against a given microbe divides rapidly to produce clones of two types of daughter cells: _______ cells, which produce the antibodies that will directly fight the invader, and _______ cells, which will remain in the body long after the infection has passed.

T cells specific to a given invader become activated by binding to a cell whose central function is to initiate adaptive immunity by displaying microbial antigens. These are the _______ cells, the most important of which is the _______ cell.