Immune System - Basic Flashcards
phagocytosis
the ingestion of invading microorganisms by certain types of white blood cells (phagocytes)
macrophages
"”big eaters””; white blood cells that destroy invading microbes and help alert other immune cells by secreting interleukin-1 (chemical regulator)
eosinophils
white blood cells that position themselves against a parasite’s body and discharge destructive enzymes that damage the invader
natural killer cells
cells that patrol the body and and attack virus-infected body cells and cancer cells by releasing a chemical that breaks down their target’s cell membrane
inflammation
injured tissues release chemicals that stimulate mast cells (connective tissue cells specialized to release histamine)
histamine
promotes vasodilation which causes redness and swelling
B lymphocytes
lymphocytes that produce antibodies; when stimulated, certain daughter cells (plasma cells) secrete large quantities of antibodies in the bloodstream
T lymphocytes
regulate the immune response or kill certain types of cells
antigens
something that elicits a specific response from a lymphocyte
antibodies
an antigen-binding protein associated with B-cells
memory cells
long-lived cells that provide future immunity
plasma cells
secrete antibodies
cytotoxic T cells
destroy foreign cells, infected body cells, or cancerous body cells; attack foreign antigen displayed with MHC-1 (responsible for rejection of tissue and organ transplants)
helper T cells
stimulate immune responses (by secreting interleukin-2) from both B cells and killer T cells
humoral immunity
involves activation and clonal selection of B cells, resulting in production of secreted antibodies that circulate in the blood and lymph
cell-mediated immunity
involves activation and clonal selection of cytotoxic T cells, which directly destroy certain target cells
vaccination
injection of weakened or killed microbes to stimulate the development of memory cells
AIDS
acquired immunodeficiency syndrome, caused by RNA viruses, destroys helper T cells, helper T cells make more viruses and infect more helper T cells, the immune response shuts down
interferon
chemical messenger produced by virus-infected body cells and capable of stimulating resistance in uninfected cells by synthesis of anti-viral enzymes
interleukin-1
chemical regulator secreted by macrophages to alert other immune cells
interleukin-2
secreted by helper T cells to stimulate immune responses in B cells and killer T cells
major histocompatibility complex
responsible for antigen presentation
CD4
surface protein present on most helper T cells the binds class II MHC molecules
CD8
surface protein present on most cytotoxic T cells that binds a class I MHC molecule to a cytoxic T cell
