Diseases that are caused by agents that have invaded the body
Pathogen
Any agent that causes disease
Koch's Postulates
"Rules" for determining the cause of the disease
Mucous Membranes
Epithelial tissues that protect the interior surfaces of the body that may be exposed to pathogens
Inflammatory Response
A series of events that suppress infection and speed recovery
Histamine
A substance that increases blood flow to the injured area and increases the permeability of surrounding capillaries
Phagocytes
Ingest and destroy pathogens and foreign matter
Neutrophil
The most abundant type of phagocyte in the body
Macrophage
Engulf pathogens and cellular debris, also a phagocyte
Natural Cell Killers
Large white blood cells that attack pathogen-infected cells -- not the pathogens themselves
Complement System
Made up of 20 different proteins, circulate in the blood and become active when they encounter certain pathogens
Interferon
A protein released by cells infected with viruses
Immune System
The cells and tissues that recognize and attack foreign substances in the body, provides the body's specific defenses
Lymphocytes
The white blood cells of the immune system
Thymus
A gland located above the heart, helps produce a special kind of lymphocyte
Spleen
The largest lymphatic organ in the body, stores healthy blood cells
B Cells
Made in the bone marrow and complete their development there
T Cells
Made in the bone marrow but complete their development only after traveling to the thymus
Antigen
Any substance that the immune system can recognize and react with
Immune Response
The reaction of the body against an antigen
Helper T Cell
A specialized lymphocyte
Cell-Mediated Immune Response
Increase in interleukin-2, which allows the T cells to divide even faster
Cytotoxic T Cells
Recognize and destroy cells that have been infected by the pathogen
Humoral Immune Response
Involves the action of B cells and occurs at the same time the cell-mediated immune response occurs
Plasma Cells
Highly specialized cells that make defensive proteins called antibodies that are released into the blood
Antibody
Binds to a specific antigen or inactivates or destroys toxins
Memory Cells
Lymphocytes that will not respond the first time that they meet with an antigen or an invading cell but will recognize and attack that antigen or invading cell during later infections
Immunity
The ability to resist an infectious disease
Vaccination
The introduction of antigens into the body to cause immunity
Asthma
A respiratory disorder that causes the bronchioles to narrow
Autoimmune Disease
A disease in which the immune system attacks the organism's own cells
HIV
AIDS results from infection by the human immunodeficiency virus
Opportunistic Infections
Illnesses caused by pathogens that produce disease in people with weakened immune systems
AIDS
When the immune system loses its ability to fight off pathogens and cancers