Vocabulary
allergen A substance that triggers an allergy.
allergy A condition that occurs when the immune system attacks a harmless foreign sub-
stance.
autoimmune disease A disease that occurs when the immune system attacks the body’s
own cells.
cancer A disease in which abnormal cells divide out of control.
carcinogen Anything that can cause cancer.
diabetes A disease in which the pancreas cannot make enough insulin.
noninfectious disease Disease that does not spread from person to person.
tumor A mass of abnormal tissue.
type 1 diabetes Thetypeofdiabetesthatoccurswhentheimmunesystemattacksnormal
cells of the pancreas.
type 2 diabetes Type of diabetes that occurs when body cells no longer respond to in-
sulin.
Points to Consider
- How do you think the body fights diseases like colds?
- How do you think it protects you from pathogens and other causes of disease?
21.3 Lesson 21.3: First Two Lines of Defense
Lesson Objectives
- Describe your body’s first line of defense against pathogens.
- Explain how inflammation helps protect you from pathogens.