Immunology and Lines of Defense Flashcards

Flashcards on Immunology and Lines of Defense

Pathogen

Microorganisms that can cause disease.

Immune System

The body's ability to defend itself against pathogens, distinguishing 'self' from 'non-self'.

Normal Flora (Gut Microbiota)

Microbes that are normally found on or in the body that do not cause disease and can be beneficial.

Innate Immunity

The first two lines of immune defense, which are non-specific and work against a wide range of pathogens.

First Line of Defense

Structures, chemicals, and processes that prevent pathogens from entering the body.

Epidermis

A physical barrier composed of multiple layers of tightly packed cells that few pathogens can penetrate.

Dermis

Provides strength and pliability to the skin to resist abrasions.

Perspiration

Inhibits growth of pathogens via salt content and contains antimicrobial peptides and lysozyme.

Sebum

Keeps skin pliable, lowers pH, and inhibits many bacteria.

Lysozyme

Mucous membranes produce this enzyme that destroys the cell wall of bacteria.

Second Line of Defense

Activated when pathogens penetrate the skin or mucous membranes.

Erythrocytes

Red blood cells that carry oxygen and carbon dioxide.

Platelets

Involved in blood clotting; also called thrombocytes.

Leukocytes

White blood cells involved in defending the body against invaders.

Granulocytes

Category of white blood cells characterized by the presence of granules in their cytoplasm.

Neutrophils

Most abundant WBC; predominant cells in pus; respond quickly after tissue injury, causing acute inflammation.

Basophils

Least common granulocyte; releases histamine and other inflammatory chemicals when activated.

Eosinophils

Main effector cells in allergic responses and asthma; also fight helminth (worm) colonization.

Agranulocytes

White blood cells without granules in their cytoplasm.

Lymphocytes

Agranulocytes most involved in specific immunity (3rd line of immune defense)

Monocytes

Agranulocytes that leave the blood and mature into macrophages, which are phagocytic cells.

Phagocytosis

The process by which cells ingest and destroy foreign matter, such as microorganisms or debris.

Extracellular Killing

Secretion of toxins or active ingredients to kill nearby microbes, virally infected cells and tumors.

Inflammation

Nonspecific response to tissue damage, resulting in heat, swelling, and pain.

Fever

Body temperature above the normal range, resulting when chemicals called pyrogens trigger the hypothalamus to increase the body’s core temperature.