When damage is “fixable”

Inflammation, healing and repair

What is the body's first response to cell or tissue damage?

Inflammation

What are the three major purposes of inflammation?

1. Destroy or contain the damaging agent

2. Initiate repair

3. Return damaged tissue to functionality

What are the major signs of inflammation described in the lecture?

• Redness

• Pain

• Swelling

• Heat

Why does redness occur during inflammation?

Blood vessels undergo vasodilatation, meaning their diameter increases and more blood enters the area

Why does swelling occur during inflammation?

Blood vessels become more permeable, allowing fluid to leave the vessels and enter surrounding tissues.

This produces edema.

Why does heat occur during inflammation?

Vasodilatation allows more warm blood to reach the injured area.

Why does pain occur during inflammation according to the lecture?

Pain is associated with changes including:

• Slower local blood flow

• Leukocyte movement through vessels

• Increased vascular permeability

• Accumulation of tissue fluid

What are the three major components of inflammation?

• Vascular dilatation

• Endothelial activation

• Neutrophil migration/activation and phagocytosis

What is vascular dilatation?

Relaxation of the smooth muscle in blood vessels, causing the vessels to increase in diameter.

What can trigger vascular dilatation?

Local tissue damage can cause mast cells to release inflammatory mediators.

Why is vascular dilatation useful during inflammation?

It allows more:

• Immune cells

• Fluid

• Proteins

to reach the injured area.

What is endothelial activation?

Changes in the cells lining the blood vessels that allow immune cells and proteins to leave the bloodstream and enter damaged tissue.

What happens to endothelial cells during activation?

They begin to separate, making the blood vessel more permeable.

Why does the lecture describe activated endothelium as a “bumpy road”?

The vessel surface becomes less smooth, which slows white blood cells down and helps them attach to the vessel wall.