Diseases and the immune System What are they?

The immune system The immune system is important to the human body. It is the system that fights against infections using cells to inactivate foreign substances or cells. The immune system is comprised of, skin, white blood cells, tonsils, spleen, lymphocytes, bone marrow, thymus glass and lymph nodes. Nonspecific defenses – these parts of the immune system do not distinguish one infectious agent from another. Theses defenses act against all invaders. Ex: skin and white blood cells Specific defenses – These defenses are effective against only one type of pathogen. Ex: antibodies Phagocytes are white blood cells that engulf pathogens by phagocytosis and destroy them.

The immune system Antibodies – are ‘Y’ shaped proteins that neutralize pathogens such as, bacteria and viruses. They defend your body and attack foreign substance. Lock and Key Fit, Examples: 1. enzymes and their substrate 2.hormones and receptor sites on the surface of target cells

The immune System: Organ Transplant All body cells have protein receptors at the cell surface. This allows the immune system to recognize their own cells versus foreign cells. Transplanted organs have different protein receptors, killer T-cells will attach the transplant. To prevent this from happening people are given organs that have cell markers that are nearly identical to their own. Patients will also take medication to suppress the killer T-cells from attacking the new organ.

The Immune System : Your behaviors You contribute to your health each and every day by: Eating healthy Exercising LOTS of rest. GO TO BED EARLY! Abstain from harmful activities Wash your hands often Regular medical check-ups

Fevers: Are they really that bad? Fevers help your body attack pathogens The increase in your body temperature slows down and/or stops the growth of many pathogens The increase in temperature also speeds up the rate of reactions that help repair damage tissue Fevers increase heart-rate which causes the white blood cells to travel to the infection faster

Diseases: What are they? Diseases are any change, other than injury, that disrupts the normal functions of the body.

Causes : Agents V. Environment

Pathogens – disease causing agents that can be living or non-living

Infectious Disease An infectious disease is caused by a pathogen that can be transmitted from person to person. Not all diseases are infectious.

Agents of infectious disease:

History of infectious disease It was once believed that evil spirits, curses and night vapors were the cause of disease Louis Pasteur and Robert Koch were scientists that studied diseases and changed the way people viewed them and thought about them. The Germ Theory: infectious diseases are caused by microorganisms of different types, commonly known as germs. Koch’s Postulates are a series of rules used to identify the microorganisms that cause a specific disease. The suspected pathogen must occur in the body of an animal with the disease and not occur in the body of a healthy animal The suspected pathogen should be isolated and grown in a laboratory culture If a healthy animal is inoculated this culture the animal should develop the disease The pathogen from the second animal should be isolated and grown in a laboratory. It should be the same as the pathogen isolated from the first animal.

The spread of disease Physical Contact: person to person through direct or indirect contact. EX: Coughing, touching, sneezing, contaminated surfaces Contaminated food/water: pathogens reside in the food and water that is eaten by humans Infected animals: fleas, ticks and mosquitoes can easily transmit a disease from one person to the next.

The Spread of Disease Vectors, carry pathogens. EX: Fleas and Ticks Vectors can cause several different diseases. Malaria, Lyme disease, West Nile virus, rabies, African sleeping sickness are some examples. Antibiotics are compounds that kill bacteria without harming human cells People can become immune to a disease after having it and surviving it. They develop a resistance to it, or immunity.