Recording-2025-03-06 Chapter12 Bio225

First line of defense

Physical and chemical barriers that block invasion at the portal of entry.

Second line of defense

Innate, non-specific responses including inflammation, fever, phagocytosis, and antimicrobial proteins.

Third line of defense

Acquired immune response involving B cells and T cells that target specific foreign substances.

Pathogen-associated molecular patterns (PAMPs)

Molecules found on pathogens that are recognized by the immune system as invaders.

Phagocytosis

The process by which phagocytes ingest and eliminate microbes and cellular debris.

Interferon

A protein produced by virally infected cells that alerts nearby cells to produce antiviral proteins.

Complement system

A group of proteins that work together to destroy bacteria and viruses through a cascade reaction.

Inflammatory response

A protective reaction involving redness, warmth, swelling, and pain due to increased blood flow and immune cell recruitment.

Neutrophils

A type of granulocyte that responds rapidly to bacterial infections.

Monocytes

White blood cells that differentiate into macrophages and dendritic cells after migrating into tissues.

Ciliated epithelium

Cells in the respiratory tract that help move trapped particles and microbes out of the airways.

Lysozyme

An enzyme found in tears and saliva that breaks down bacterial cell walls.

Sebum

Oily secretion from sebaceous glands that moisturizes skin and provides a barrier against pathogens.

Mucous membranes

Tissues that line body cavities and secretes mucus, preventing pathogen entry.

Endospores

Highly resistant structures formed by some bacteria, allowing them to survive extreme conditions.

Diapedesis

The process by which phagocytes move out of blood vessels and into tissues.

Fever

An elevated body temperature that can inhibit pathogen growth and enhance immune response.

Vasodilation

The widening of blood vessels that increases blood flow to a specific area, contributing to inflammation.

Antimicrobial peptides

Small proteins that can insert into microbial membranes and disrupt their integrity.

Resident macrophages

Macrophages that live in specific tissues (histiocytes) to monitor and respond to pathogens.

Cytokines

Signaling molecules that mediate and regulate immunity and inflammation.