Immune System Flashcards

Flashcards to help study the immune system, innate and adaptive immunity, and related clinical connections.

Immune System

Protects us from infectious agents and harmful substances; composed of numerous cellular and molecular structures; function together to provide us with immunity; function dependent on specific type of infectious agent

Nonspecific or Innate Immunity

Present at birth; acts against all microbes the same way – nonspecific; first line of defense; second line of defense

Specific or Adaptive Immunity

Involves activation of specific lymphocytes that combat a particular pathogen or other foreign substance; T cells and B cells

Innate Immunity

Protect against numerous different substances; born with these defenses; does not require previous exposure to a foreign substance; respond immediately to potentially harmful agent

Innate immunity: First line of defense

Skin/Epidermis, Mucous membranes, Chemicals

Innate immunity: Second line of defense

Antimicrobial substances, Phagocytes, Natural killer cells (NK cells), Inflammation, Fever

Inflammation

Nonspecific, defensive response of the body to tissue damage

Inflammatory response 3 basic stages

Vasodilation and increased permeability of blood vessels, Emigration of phagocytes from the blood into interstitial fluid, Tissue repair

Fever

Abnormal elevation of body temperature by hypothalamus; at least 1°C from normal (37°C)

Benefits of fever

Inhibits reproduction of bacteria and viruses, increases activity of adaptive immunity, accelerates tissue repair

Adaptive immunity

Ability of the body to defend itself against specific invading agents

Antigens

Substances recognized as foreign that provoke immune responses

Adaptive Immunity

B cells and T cells

Cell-mediated

Cytotoxic T cells directly attack invading antigens

Antibody-mediated

B cells transform into plasma cells, which synthesize and secrete specific proteins called antibodies or immunoglobulins

Immunogenicity

Ability to provoke an immune response by the production of antibodies, T cells, or both

Reactivity

Ability of antigen to react specifically with antibodies or cells

Epitopes

Small parts of a large antigen molecule that act as the triggers for immune responses

MHC

In plasma membrane of body cells are “self-antigens” known as major histocompability complex (MHC) antigens also known as human leukocyte antigens

Clonal selection

Lymphocyte proliferates and differentiates in response to a specific antigen; forms many lymphocytes capable of fighting off infection

Antibody-Mediated Immunity – B cells

Helper T cells costimulate the B cell so the B cell can proliferate and differentiate into a clone of effector cells that produce millions of antibodies for about 4 or 5 days

Immunological memory

Due to presence of long-lasting antibodies and memory B and T cells

Primary response

Measurable response of antibody production to first exposure

Lag or latent phase

Much shorter with subsequent exposures; due to memory lymphocytes

Subsequent exposures/secondary response

Measurable response termed the secondary response

Vaccinations

Weakened or dead microorganism (attenuated); Stimulate immune system to develop memory B- lymphocytes; Provide relatively safe means for initial exposure to microorganism

Pus

Contains destroyed pathogens, dead leukocytes, macrophages, cellular debris

Abscess

Pus walled off with collagen fibers

Hypersensitivities

Abnormal and exaggerated response of immune system to antigen

Autoimmune disease

Occurs when the immune system fails to display self-tolerance and, instead, attacks the person’s own body tissue(s)

Acquired immunodeficiency syndrome (AIDS)

A condition in which a person experiences an assortment of infections due to the progressive destruction of immune system cells by the human immunodeficiency virus (HIV)