Chapter 20
Resistance and the Immune System:
Innate Immunity
Chapter Summary and Essay Questions
In Chapter 20, attention turns from the parasite to the host. The text describes mechanisms used
by the host to resist disease. Mechanical and chemical barriers, phagocytosis, inflammation, and
complement mechanisms, and interferon are surveyed as examples of nonspecific or innate
resistance. On completing the chapter, you should be able to answer the following essay
questions:
a. Describe the major fluid and cellular components of the human circulatory system, especially
as they relate to the lymphatic system and the defense against disease.
b. Describe and compare the six types of leukocytes and how they function.
c. Outline the basic components and functions of the lymph and the lymphatic system.
d. Compare and state some specific examples of the broad types of nonspecific resistance.
e. List the physical and chemical barriers of innate immunity and judge the role of each as a
defense against infectious disease.
f. Describe the process of phagocytosis, and assess its effectiveness as a second line of body
defense against infection.
g. Identify the four characteristic signs of inflammation, and describe how an inflammatory
response develops from an infection.
h. Explain how a fever can provide nonspecific resistance to disease.
i. Summarize the role of natural killer (NK) cells in innate immunity.
j. Construct a chart showing how complement acts to mark pathogens for destruction.
k. Assess the role of pathogen-associated molecular patterns (PAMPs) and toll-like
receptors and in innate
immunity.
l. Describe the role of interferon as a defense mechanism against virus infection.