Nonspecific immune defenses

The immune system protects your body from pathogens

Resistance

• Resistance is your bodies ability to defend against pathogens.

• Your immune system gives you resistance.

physical barriers to disease

• Nonspecific defense.– Sweat, oils, &

waxes.– Mucous

membranes.– HCL of stomach.

Why you get a fever

• Pathogens that attack human body like 98.6° F best.

• Raising temperature of body increases effectiveness of white blood cells.

• Decreases effectiveness of pathogen.

Interferon

• Chemical released by cells infected by viruses.

• Causes surrounding cells to resist infection.

Inflammatory Response

• Symptoms:– Redness– Heat– Swelling, pain

• What occurs:– Damaged cells

release histamines.

– Causes vasodialation

– Causes increase in permeability.

•Inflammatory response occurs when pathogen penetrates the skin.

Pair share: explain this picture to your partner. What is happening in each frame?

Neutrophils

• Most common white blood cell

• Kill pathogens using phagocytosis.

• Circulate in blood stream.

• Migrate towards site of infection.

• Move out of the blood stream

Macrophages

• Stationed in certain tissues.• Destroy by phagocytosis.• Rid the body of debris and damaged cells.

Natural Killer Cells

• Attack cells which have been infected by pathogen.

• Kills cancer cells.

• Kills by puncturing cell membrane.

summary

1. List 3 nonspecific defense barriers.

2. List 3 symptoms of the inflammatory response.

3. What do macrophages do?