21. The Immune System

Mark the following statements as true or false. If a statement is false, correct it to make a true statement.

NK cells are cytotoxic cells that lyse and kill cancer cells and cells infected with certain viruses.

Give a function for each of the following:

(l) Interleukins

(m) Tumor necrosis factor

(n) Colony-stimulating factors

Interferons are referred to as antiviral proteins. What stimulates their production, and how do they protect uninfected cells?

Compared with innate defenses, adaptive defenses

(a) Do not distinguish between one threat and another

(b) Are always present at birth

(c) Protect against threats on an individual basis

(d) Deny the entry of pathogens to the body

Mr. White has been diagnosed with febrile neutropenia, a condition characterized by the presence of a fever with an extremely low number of neutrophils in the blood. Blood work demonstrates the presence of bacteria in his blood. Explain why neutropenia might lead to a bacterial infection. Why is a bacterial infection particularly dangerous for Mr. White?

Phagocytes move through capillary walls by squeezing between adjacent endothelial cells, a process known as

(a) Diapedesis

(b) Chemotaxis

(c) Adhesion

(d) Perforation

The process by which neutrophils squeeze through capillary walls in response to inflammatory signals is called:

a. Diapedesis

b. Chemotaxis

c. Margination

d. Opsonization

Interferons are referred to as antiviral proteins. What stimulates their production, and how do they protect uninfected cells? Which cells of the body secrete interferons?