lymph nodes
small, encapsulated structures that contain lymphocytes, macrophages, and dendritic cells
screen and filter the lymph for pathogens
MALT
composed of B and T lymphocytes and found throughout the gastrointestinal and respiratory tracts in areas that are especially vulnerable to pathogens from the external environment
kill pathogens entering the body
Spleen
consists of red and white pulp; red pulp contains macrophages that destroy old erythrocytes while white pulp surrounds small arteries and contains leukocytes that detect and destroy pathogens
filters the blood for pathogens
Thymus
located in the mediastinum and is composed of two lobes, each containing many thymic lobules consisting of an outer cortex and an inner medulla
site of T cell maturation
Tonsils
specialized clusters of partially encapsulated MALT in throat made up of lymphoid follicles (nodules)
kill pathogens entering the body
antibody
Y-shape protein structures produced by plasma cells that possess an antigen-binding site specific to the antigen they detect;
antigens
antigens are substances that trigger the production of antibodies.
B Lymphocytes
perform humoral immunity and include plasma cells (antibody producing cells) and memory B cells
T Lymphocytes
perform cell-mediated immunity and include Helper T cells.
Cytotoxic T cell
T cells kill infected cells
Helper T cells:
T lymphocytes (helper T cells) recognize the antigen and release chemicals that cause the proliferation of cytotoxic T cells and B cells
memory B cells
are long-lived cells that are activated by subsequent exposure to a specific antigen and do not produce antibodies but direct the proliferation of plasma cells
plasma cells
produce antibodies
nonspecific immunity
includes physical barriers (skin and mucous membranes), fever, the inflammatory response, phagocytosis, and the complement system;
specific immunity
involves B and T cells and proteins that recognize and respond to only one pathogen as well as production of memory B and T cells that produce a stronger and quicker second responds to a second encounter to an antigen