22 Immune System and Body_s Defenses.docx - Chapter 22:...

Chapter 22: Immune System and the Body’s Defense
I. 22.1 Overview of Diseases Caused by Infectious Agents (p.842-843)
A. Compare and contrast the five major classes of infectious agents.
1. Infectious agents
a. Organisms that invade other organisms (the host), causing damage and possibly death
b. Are considered pathogenic when they cause harm
c. Five major categories
i. Bacteria
A. Microscopic, single-celled organisms
B. Prokaryotic cells (compared to the eukaryotic cells of humans)
C. Three categories based on shape
i. Cocci (spherical)
ii. Bacilli (rodlike)
iii. Spirilla (coiled)
D. Virulence
i. Ability of a pathogen to cause illness
ii. High virulence = very likely to make someone sick
ii. Viruses
A. Not cells; it is debated whether they are alive or not
B. Smaller even than bacteria
C. Only made of a protein shell containing either RNA or DNA
D. Obligate intracellular parasites – they must enter a cell in order to reproduce
E. They inject their genetic material into a cell, and then use the cell’s machinery (RNA,
ribosomes, etc.) to make new viruses that burst out of the cell and go on to infect more
cells; this process kills the infected cell.
F. Cause diseases such as HIV, common cold, herpes
iii. Fungi
A. Eukaryotic cells (have a nucleus and organelles)
B. Have a cell wall
C. Includes molds, yeasts, and spore-producing fungi
D. Irritation occurs in host when fungi release enzymes to break down host proteins for them
to eat.
E. Cause diseases such as ringworm, yeast infections, athlete’s foot
iv. Protozoan
A. Also eukaryotic
B. No cell wall
C. Cause infections such as malaria and trichomoniasis
v. Multicellular parasites
A. Small, but not microscopic
B. Ex. Parasitic worms such as tapeworms
B. Describe prions, and name a disease they cause.
II. 22.2 Overview of the Immune System (p.843-846)
A. 22.2a Immune Cells and Their Locations (p.843-844)
1. List the types of leukocytes of the immune system, and describe where they may be found.
1

ii. Monocytes become macrophages when they exit blood vessels and settle in the tissues.
iii. Three types of lymphocytes
A. T-lymphocytes
B. B-lymphocytes
C. NK (natural killer) cells
c. Where leukocytes are found
i. Lymphatic tissue
A. Lymphatic structures as lymph nodes, spleen, tonsils, MALT, and lymphatic nodules
B. T-lymphocytes, B-lymphocytes, NK cells, as well as macrophages are found here
ii. Some organs
A. Macrophages can reside in organs such as the lungs and brain.
B. Fixed macrophages are permanent to those organs.