They Make Us Sick Diseases

Bacteria A disease is anything that causes your body to stop working properly Bacteria are microscopic, unicellular (one cell) organisms There are thousands of them Bacteria are an important part of the natural environment They are decomposers Bacteria living in the intestines of herbivores help with digestion

Bacterial diseases Pathogenic bacteria causes hundreds of diseases eg. Whooping cough, meningococcal disease These are all infectious diseases, they are diseases that can be spread Some infectious diseases are easier to spread than others Those that are easiest to spread are described as contagious

Quarantine is used to prevent the spread of disease within a community, between communities and between countries Bacterial infections are treated with antibiotics The first successful antibiotic was penicillin Before the development of antibiotics, you had to depend on your body’s immune system to fight off infection

Does Antibacterial Soap Really work? Prac

Parasites Parasites are organisms that lives in or on another organism. The parasite benefits while usually harming the host organism. Parasites that live inside your body are called endoparasites and those that live outside your body are called ectoparasites

Prions They are non-cellular pathogens They are abnormal and infectious proteins that can convert your normal protein into prion protein. When cells containing prions burst the infectious proteins are released to infect other cells

Viruses Viruses caused many common illnesses, such as colds and flu, measles, chicken pox and polio Viruses are smaller than bacteria Viruses only reproduce in cells they have invaded – host cells

A virus uses the host cell to make thousands of copies of itself The host cell is destroyed when it bursts open and releases new viruses that spread throughout the body, infecting and destroying other cells

Fungi Fungi organisms, such as mushrooms and moulds, that help to decompose dead or decaying matter. Many are parasites, and these can lead to disease. Many fungi are parasites, feeding on living plants and animals Common human diseases caused by fungi are tinea , ringworm

The Immune System Pathogens can enter your body a number of ways eg. Food, water, breathing in, cuts, sexual contact Your body has three lines of defence. The first line of defence is to stop pathogens entering the body. Eg. the skin, tears and saliva, nose hairs and mucous lining the trachea; and the chemical barriers such as saliva, tears, stomach acid

Once the pathogen enters the body tissues, the second line of defence starts: inflammation White blood cells consume the bacteria, and the dead white blood cells form the yellow pus that collects around the wounds Third line of defence is the lymphatic system, which contains lymph nodes which has different types of white blood cells , which destroy pathogens

Vaccination To help out the immune system vaccines are used Vaccines are chemicals that cause your body to react as if it met a pathogen

A vaccine is created by taking a small amount of poison produced by the bacterium and making it inactive, or by using dead bacteria The inactive poison and the dead bacteria are harmless, but your immune system responds to the vaccine by making antibodies and you become immune to the pathogen

Modelling the transmission of diseases Prac