Immune System Flashcards

Flashcards about the Immune System.

The Immune System

An organism’s defense system against pathogens.

Innate Immune System

The first line of cellular defense and generates a rapid, nonspecific immune response.

External Immunity

Physical and chemical barriers prevent pathogen entry.

Skin

Oily and acidic secretions from sweat glands kill microbes; the first barrier to pathogens and viruses.

Antimicrobial proteins

Lysozyme in saliva and tears break down microbial cell walls.

Cilia

Lines the lungs and sweeps invaders out.

Gastric juice

Stomach acid kills microbes.

Interferons

Are secreted by infected cells that stimulate neighboring cells to produce proteins to defend against viral infections.

Cytokines

Chemical signaling molecules used in the immune response for cell-cell communication.

Interleukins

Specific type of cytokine involved in the inflammatory reaction; triggers the adaptive immune response.

Phagocytic leukocytes

Engulf foreign particles, bacteria, and dead cells via phagocytosis.

Neutrophils

Function in the destruction of pathogens in infected tissues.

Monocytes

Circulate in blood until they move into tissues via diapedesis where they develop into macrophages.

Macrophages

In tissues, they phagocytize cell debris and pathogens, and are derived from monocytes.

Dendritic cells

Ingest pathogens and stimulate the acquired immune response.

Mast Cells

Function in an allergic response, inflammatory response, and anaphylaxis.

Eosinophils

Surround and destroy multicellular parasites.

Basophils

Release histamine in the inflammatory response and are recruited to tissues when needed.

NK Cells

Attack abnormal body cells, either tumors or pathogen-infected cells.

Complement System

Contains complement proteins that circulate the body and assist in activating the immune response.

Toll-like Receptors (TLRs)

Critical to innate immunity and are key proteins that link innate and acquired immunity; recognize molecular patterns that many pathogens have.

Adaptive Immune System

The specific, third, and last line of immune defense that develops after the body has been attacked; the immune response targets specific antigens.

Antigens

A specific foreign pathogen or molecule that can trigger an immune response.

Epitopes

A specific part of an antigen to which an antibody binds.

Antibodies

Proteins that bind to a specific antigen they recognize.

Lymphocyte

Primary cells of the adaptive immune response; originate in the bone marrow and concentrate in lymphatic tissue such as lymph nodes, thymus gland, and spleen.

B Cells

Originate and mature in the bone marrow, and are activated in response to foreign antigens.

T Cells

Originate in the bone marrow but mature in the thymus, and have antigen receptors.

Cytotoxic T cells

Killer T cells that destroy by releasing perforin protein and via lysis.

Helper T cells

Stimulate activation of B cells, cytotoxic T cells, and suppressor T cells.

Suppressor T cells

Play a negative feedback role in the immune system.

Memory T cells

Similar in function to Memory B cells

Plasma Cells

B cells that circulate in the blood and release specific free antibodies that dispose of antigens by agglutination, inactivation, opsonization, and lysis.

Memory Cells

Long-lived B cells that store memory of an antigen they have encountered; they then circulate in the body, proliferate, and respond quickly to eliminate subsequent invasion by the same antigen.

Major Histocompatibility Complex (MHC)

A collection of glycoproteins that exists on membranes of all body cells.

Humoral response (antibody-mediated response)

Occurs when extracellular pathogens are recognized in the blood or lymph; B-cells are then stimulated to produce antibodies that lead to the destruction of the pathogen.

Active Immunity

Acquired after direct exposure to an infection/vaccine; natural or artificial.

Passive Immunity

Acquired from external sources; natural or artificial.

Antibiotics

Facilitate human immune responses by killing or inhibiting the growth of bacteria by disrupting their biological mechanisms.

Cell-Mediated Response

Occurs when an infected cell is recognized and bound by a T-cell; the T-cell then activates other T-cells, causing proliferation that leads to lysis of the infected cell.

Vaccines

Build immunity to a specific part of a pathogen by placing a weak end or dead form of the pathogen via a preventative technique.

Antigen Presenting Cells (APCs)

Macrophages, dendritic cells, and B cells.