Overview of the Immune System and Inflammation

Innate Immunity

First line of defense against pathogens.

Adaptive Immunity

Targets specific antigens for immune response.

Antigens

Foreign substances that trigger immune responses.

Memory Cells

Store information for faster future immune responses.

Neisseria gonorrhoeae

Bacteria demonstrating immune system interaction.

Complement System

Enhances ability to clear pathogens from body.

Inflammation

Response to injury or infection, causing swelling.

Immune Response

Body's reaction to foreign substances or pathogens.

Gonorrhoeae

Bacteria that can survive and produce antibodies.

Antibodies

Proteins from adaptive immunity that bind foreign invaders.

Red Blood Cells

Cells in blood responsible for oxygen transport.

White Blood Cells

Cells in blood that fight infections.

Platelets

Cell fragments involved in blood clotting.

Myeloid Stem Cells

Precursors for certain white blood cells.

Lymphoid Stem Cells

Precursors for lymphocytes in adaptive immunity.

Polymorphonuclear Leukocytes

WBCs with multilobed nuclei; include neutrophils.

Neutrophils

Most abundant WBCs; engulf microbes via phagocytosis.

Phagocytosis

Process of engulfing and destroying microbes.

Basophils

WBCs that release toxic products, not phagocytic.

Eosinophils

WBCs that combat parasites and allergic responses.

Mast Cells

Cells that release histamine; involved in allergies.

Monocytes

WBCs that differentiate into macrophages or dendritic cells.

Macrophages

Phagocytic cells that present antigens to T cells.

Dendritic Cells

APCs located in spleen and lymph nodes.

Lymph Nodes

Secondary lymphoid organs that detect pathogens.

Skin

Physical barrier; keratinocytes inhibit microbial growth.

Mucous Membranes

Interface that traps microbes with secreted mucus.

GALT

Gut-associated lymphoid tissue; includes Peyer's patches.

Peyer's Patches

Lymphoid tissue sampling intestinal microbes.

M Cells

Cells that transport microbes across intestinal epithelium.

Mucociliary Elevator

Mechanism in lungs to trap and expel microbes.

Acute Inflammation

Response allowing WBCs access to infected tissues.

Vasoactive Factors

Substances increasing blood vessel permeability.

Vasodilation

Widening of blood vessels to increase blood flow.

Chronic Inflammation

Persistent inflammation causing tissue damage.

Interferon

Cytokines that enhance viral defenses in cells.

Natural Killer Cells

WBCs that kill cancerous or infected host cells.

Toll-Like Receptors

Receptors recognizing microbial patterns to activate immunity.

Fever

Body's response to infection; regulated by pyrogens.

Complement System

Proteins that enhance immune response and kill pathogens.

Membrane Attack Complexes

Pores formed by complement proteins in pathogens.

Alternative Pathway

Complement activation that does not require antibodies.

Classical Pathway

Complement activation dependent on antibodies.

Lectin Pathway

Complement activation requiring mannose-binding lectin.