Innate Immunity

First Line of Defense

Skin and mucous membranes that are impenetrable to most pathogens.

Second Line of Defense

Includes leukocytes, macrophages, NK cells, fever, inflammation, and antimicrobial proteins that respond to pathogens that breach the first line.

Third Line of Defense

Adaptive immunity that defeats and remembers pathogens for quicker responses in future encounters.

Innate Immunity

The non-specific defenses present from birth, involving the first and second lines.

Adaptive Immunity

The specific immune response involving the third line, allowing for immune memory and adaptation to pathogens.

Acid Mantle

A thin film of fatty and lactic acids in sweat and sebum that prevents bacterial growth.

Dermicidin

An antibacterial peptide found in sweat.

Defensins and Cathelicidins

Peptides that destroy bacteria, fungi, and viruses.

Hyaluronic Acid

A ground substance in mucous membranes that hinders microbial movement.

Fever

Speeds up recovery by promoting interferon activity and preventing bacterial and viral reproduction.

Inflammation

Local defense response to tissue injury involving redness, swelling, heat, pain, and cytokines.

Cytokines

Proteins that facilitate communication among immune cells.

Margination

The process of leukocytes adhering to the walls of blood vessels during inflammation.

Diapedisis

The movement of leukocytes through the endothelial gaps to enter tissues.

Abscess

A pocket of accumulated pus consisting of dead tissues, cells, and debris.