CK-12 Foundation
Ck 12: Barriers to Pathogens
[Free Registration/Login may be required to access all resource tools.] In the following tutorial you will learn about the barriers that keep most pathogens out of the human body.
CK-12 Foundation
Ck 12: Biology: Barriers to Pathogens
[Free Registration/Login may be required to access all resource tools.] Explains the body's first line of defense against pathogens, such as the skin and body fluids.
CK-12 Foundation
Ck 12: Life Science: Barriers to Pathogens
[Free Registration/Login may be required to access all resource tools.] Your body has many ways to protect you from pathogens. Your body's defenses are like a castle. The outside of a castle was protected by a moat and high walls. Inside...