Chapter 21: The Immune System Overview

These flashcards cover key concepts in the immune system's innate and adaptive defenses, highlighting important definitions and processes.

Innate Immunity

The first line of defense in the immune system, providing nonspecific resistance to disease and responding quickly to pathogens.

Adaptive Immunity

The third line of defense in the immune system, providing specific resistance to disease and memory for quicker responses upon re-exposure to pathogens.

Phagocytosis

The process by which phagocytes recognize, engulf, and destroy pathogens through cellular ingestion.

Inflammation

A nonspecific response to tissue injury characterized by redness, heat, swelling, and pain, aimed at preventing further injury and initiating healing.

Opsonization

The process of marking pathogens with opsonins (such as antibodies or complement proteins) to enhance phagocytosis.

Cytokines

Chemical signals released by immune cells that mediate and regulate immunity, inflammation, and hematopoiesis.

Natural Killer Cells (NK Cells)

A type of lymphocyte that provides immune surveillance and destroys abnormal or infected cells by inducing apoptosis.

Complement System

A group of plasma proteins that enhance the body’s immune response by promoting inflammation, phagocytosis, and cell lysis.

Antigens

Substances that the immune system recognizes as foreign and which can provoke an immune response.

Memory Cells

Long-lived immune cells that remember past infections and enable a faster and stronger response upon future exposures to the same pathogen.