cont.

B Lymphocytes (B Cells)

Differentiate into plasma cells that produce antibodies.

Macrophages

Phagocytic cells that process and present antigens to T cells.

Dendritic Cells

Antigen-presenting cells that alert the immune system.

Reticular Cells

Contribute to the structural framework of lymphatic organs.

What are the secondary lymphatic organs?

Lymph nodes, tonsils, spleen (where immunocompetent cells are activated).

what is innate immunity

General defenses, present at birth, non-specific, includes skin, mucous membranes, leukocytes, and inflammatory response

Cytotoxic T cells

attack infected cells

Helper T cells

coordinate immunity

Regulatory T cells

prevent overreaction

Memory T cells

provide long-term immunity

IgG

Most abundant, crosses placenta, secondary response

IgA

Found in secretions (tears, saliva, breast milk).

IgM

First produced in infection, pentamer structure.

IgE

Involved in allergic reactions and parasite defense.

IgD

Functions in B cell activation.

what is active immunity

Body produces its own antibodies (natural: infection; artificial: vaccine)