CK-12 Foundation
Ck 12: Life Science: Circulation and the Lymphatic System
[Free Registration/Login may be required to access all resource tools.] The lymphatic system is a network of vessels and tissues that carry a clear fluid called lymph. The lymphatic system works with the cardiovascular system to return...
CK-12 Foundation
Ck 12: Life Science: Lymphatic System
[Free Registration/Login may be required to access all resource tools.] If pathogens get through the body's first two lines of defense, a third line of defense takes over. This third line of defense involves the immune system. The immune...