Chapter 21: The Immune System

These flashcards cover key vocabulary related to the immune system, including defenses, cell types, and responses.

Innate Defenses

The body's first line of defense against invading pathogens; nonspecific and includes surface barriers such as skin and mucous membranes.

Phagocytosis

A process in which cells (like phagocytes) ingest and destroy foreign particles or pathogens.

NK Cells

Natural Killer cells; a type of lymphocyte that destroys abnormal cells, including cancerous or virus-infected cells.

Inflammation

A bodily response to tissue damage characterized by redness, pain, heat, and swelling, aimed at preventing the spread of damage and initiating repair.

Acquired Immunity

A type of immunity that develops after exposure to specific pathogens; involves the activation of lymphocytes and the creation of memory cells.

B Cells

A type of lymphocyte that produces antibodies and contributes to humoral immunity.

Antibodies

Proteins produced by plasma cells (derived from B cells) that specifically target and neutralize foreign antigens.

T Cells

A type of lymphocyte that is responsible for cell-mediated immunity, including helper and cytotoxic T cells.

Antigen

Any substance that the immune system can recognize as foreign, provoking an immune response.

Autoimmunity

A malfunction of the immune system where it attacks the body's own tissues and cells.

Allergy

An immune response to a usually harmless substance (allergen), resulting in symptoms that can range from mild to severe.