21. The Immune System

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?

Eileen presents with flu-like symptoms, including fever, chills, and body aches.

You order blood work and find that the number of neutrophils in the blood is greatly elevated. What does this tell you about the likely type of pathogen involved? Explain.

Which of the following statements about phagocytosis is incorrect?

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

Fever is generated by pyrogens that reset the temperature set point of the hypothalamus to a lower value.

What seven defenses, present at birth, provide the body with the defensive capability known as innate (nonspecific) immunity?

What is complement? How does it cause bacterial lysis? What are some of the other roles of complement?