body's ability to recognize and defend itself against specific invaders and their products, a dual system with humoral and cellular components

Adaptive/Specific Immunity:

1. specificity: are precisely tailored to attacker

2. Inducibility: specific antigen induces cells of adaptive immunity

3. Colonality: induced cells proliferate for many generations of clones

4. Unresponsiveness to self: does not act against normal body cells

5. Memory: adapts to respond faster/more effectively in subsequent encounters

Tissues and Organs: Lymphatic System

colorless, watery liquid, arises from interstitial fluid

1 way system that conducts lymph

lymphocytes lie in lymph nodes for foreign antigens, each lymph node receives lymph from numerous vessels

contain stem cells that give rise to cells of specific immunity

smallest leukocytes, B and T lymphocytes, large round nucleus with thin rim of cytoplasm, act against specific pathogens and are identical under the microscope

mature in red marrow of adults, identified by surface proteins, found primarily in spleen, lymph nodes, red marrow, and Peyer's patches, only a few circulate, secret antibodies

Lymphocytes:

cells B cells actively fighting exogenous antigens

Lymphocytes:

soluble proteinacious antigen-binding molecules