Basic Concepts of Immunity and Inflammation Lecture Notes

Vocabulary flashcards covering the basic concepts of the immune system, oral defense mechanisms, leukocytes, and the inflammatory response as described in the lecture notes.

Immune System

A complex body defense system that protects the body against bacteria, viruses, fungi, toxins, and parasites.

Innate Immune System

A subdivision of the immune system present at birth, not antigen specific, present at all times, and does not improve with repeated exposure to infectious agents.

Adaptive Immune System

A subdivision of the immune system that develops throughout life, is antigen specific, has a lag time between infection and response, and develops memory providing lifelong immunity.

Host Response

The way an individual’s body responds to an infection by sending certain cells to the site and producing biochemical substances to counteract foreign invaders.

GCF (Gingival Crevicular Fluid)

Fluids that flow into the sulcus from adjacent gingival connective tissue; flow increases during inflammation to deliver cellular defenders to the site.

Oral Epithelium

A defense mechanism that prevents bacteria and their by-products from entering underlying tissues.

Polymorphonuclear Leukocytes (PMNs)

Also called neutrophils; rapid responders that provide the 1st line of defense by capturing and destroying bacterial invaders.

Phagosome

A component that engulfs bacteria during the immune response.

Lysosome

An enzyme used to break down waste, old organelles, and pathogens.

Chemotaxis

The movement of cells toward a chemical signal, such as PMNs being attracted to bacteria.

Macrophages

Phagocytic cells that engulf and destroy bacteria; called monocytes when in the bloodstream and macrophages when within tissue.

Transendothelial Migration

The "exit step" from the bloodstream where cells physically exit the blood to reach the site of infection.

Phagocytosis

The process by which leukocytes engulf (surround) and digest microorganisms.

Lymphocytes

Small white blood cells (B cells and T cells) that play an important role in recognizing and controlling foreign invaders.

B-Lymphocytes (B Cells)

Cells that make Y-shaped proteins called antibodies and secrete them into the bloodstream.

Plasma B Cells

A type of B cell that produces antibodies.

Memory B Cells

Cells that remember previous infections and help the body respond faster during subsequent exposures.

Antibody

A Y-shaped protein where the tip attaches to the antigen to neutralize bacteria, coat them for phagocytosis, or activate the complement system.

T-Lymphocytes (T Cells)

Cells that increase the response of other immune cells and produce cytokines to further stimulate the immune response.

Cytokines

Powerful proteins released by host immune cells that act as signaling molecules to alert and activate the immune system.

Complement System

A group of proteins in the blood that help fight infection by direct destruction of pathogens, opsonization, recruitment of phagocytes, and immune clearance.

Membrane Attack Complex

A protein created by the complement system that can puncture cell membranes of certain bacteria, leading to lysis.

Opsonization

The process of coating bacteria so phagocytes can eat them more easily; considered one of the most important actions of the complement system.

Immune Clearance

The "housekeeping" function of the complement system where it removes immune complexes from circulation.

Acute Inflammation

Short-term inflammation that helps protect and heal the body, moving WBCs and plasma to the area to return the body to homeostasis.

Chronic Inflammation

Long-term inflammation where the immune response can become too strong and damage tissues, characterizing condition like periodontitis.