Non-specific response

Occurs when an infection is relatively localised.

• Mast cells and white blood cells release histamines.
• The histamines cause the blood vessels to dilate = LOCAL HEAT and REDNESS
• The locally raised temperature reduces the effectiveness of pathogen reproduction in the area
• The capillary walls become more permeable
• Plasma, white blood cells and antibodies are forced out of the capillaries, causing SWELLING and PAIN.
• White blood cells and antibodies destroy the pathogens

The hypothalamus maintains a normal body temperature. When a pathogen infects the body. The hypothalamus rests to a higher body temperature.

This helps combat infection in two ways:

• Reduces pathogen reproduction
• The specific response works better at higher temperatures

If the body temperature rises oo much, enzymes will denature = permanent tissue damage

Two types of white blood cells: GRANULOCYTES and AGRANULOCYTES.

Main types of phagocytes:

• NEUTROPHILS: granulocytes, make up 70% of white blood cells
• MACROPHAGES: agranulocytes, make of 4%

They accumulate at the sie of infection to attack invading pathogens.

These are proteins that inhibit viral replication within the cells.

Effective against viruses ONLY.

• An interferon diffuses from the cell where it was made into the surrounding cells.
• It binds to receptors in the surface membranes of uninfected cells
• Stimulates a pathway which makes the cells more  resistant to infection by viruses by preventing viral  reproduction
• Prevents the infection of more cells when viruses break out of the first cell.