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 •Inflammatory response occurs when pathogen penetrates the skin. • Symptoms: – Redness – Heat – Swelling, pain • What occurs: – Damaged cells release histamines. – Causes vasodialation – Causes increase in permeability. 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. White board Review 1. List 3 nonspecific defense barriers. 2. List 3 symptoms of the inflammatory response. 3. What do macrophages do?