Immune System Concept Notes

These flashcards cover key vocabulary related to the immune system, including definitions of important terms and concepts.

Pathogen

A microorganism (like a bacterium) or virus that can cause disease.

Antigen

Anything that causes an immune response; the part of a pathogen our body recognizes as foreign.

Antibody

Proteins used by the immune system to bind to antigens and neutralize pathogens.

Innate Defenses

Non-specific immune responses including physical barriers and rapid responses.

Adaptive Defenses

Specific immune responses that are acquired and involve B cells and T cells.

Phagocytosis

The ingestion of pathogens by defensive cells like phagocytes.

Natural Killer (NK) Cells

Defensive cells that kill infected or cancerous cells by triggering apoptosis.

Inflammation

A nonspecific response to tissue injury marked by chemical signaling and mobilization of immune cells.

Humoral Immunity

A type of adaptive immunity mediated by antibodies produced by B cells.

Cellular Immunity

A type of adaptive immunity involving T cells that directly kill infected or cancerous cells.

Vaccination

A substance used to stimulate the immune system to guard against diseases.

Memory Cells

B cells that allow for a quicker response to previously encountered antigens.

Antigen-Presenting Cells (APCs)

Cells that engulf antigens and present their fragments on their surfaces for T cells.

Helper T Cells

A type of T cell that helps activate B cells and other T cells.

Cytotoxic T Cells

T cells that directly attack and kill other cells.

Regulatory T Cells

T cells that moderate the immune response.