disease

Disease

Pathogens cause infectious Diseases.

-Pathogens are any organism that causes a disease.

- Pathogens include micro organisms & larger organisms (tapeworms).

- Pathogenic micro organisms include some bacteria, some fungi and all viruses

Pathogens can penetrate an organism’s interface with the environment

· Need to enter body to cause disease. Get in through an organisms surface of contract (interface with the environment) e.g. nose, eyes and cut.

· Organism has three main interfaces with environment (gas exchange system, skin and digestive system)

1. Gas exchange system – breathe in air contains pathogens – most trapped in mucus lining of lung epithelium (outer layer of cells – passages to lungs). Cells have cilia (hair like structures) beat & move mucus up trachea to mouth where it’s removed. Some pathogens still able to reach alveoli where they invade cells and can cause damage.

2. Skin – if damage skin, pathogens on surface can enter y our bloodstream. Blood clots area of damage to prevent pathogens from entering (some many get…