Disease

Pathogens cause infectious diseases

1. A pathogen is any organism that causes disease
2. Pathogens include microorganisms and some larger organisms e.g tapeworms
3. Pathogenic microorganisms include some bacteria, some fungi and all viruses

Pathogens cause infectious diseases

1. A pathogen is any organism that causes disease
2. Pathogens include microorganisms and some larger organisms e.g tapeworms
3. Pathogenic microorganisms include some bacteria, some fungi and all viruses

Pathogens can penetrate an organism's interface with the environment  Pathogens need to enter body to cause disease- get in through organism's surface of contact (interface) with the environment e.g. nose, eyes, cuts         3 main interfaces with the environment 1. Gas exchange system - Most air breathed in containing pathogens will be trapped in mucus lining lung epithelium. These cells have a cilia that beat and move the mucus up the tranches to the mouth where its removed. But, some are still able to reach alveoli where they invade cells and cause damage 2. Skin - if you damage your skin, pathogens on the surface can enter your bloodstream. The blood clots at the area of damage to prevent pathogens entering, but some may get in before the clot forms 3. Digestive system - Most pathogens on food killed by acidic conditions of stomach. But, some can survive and pass into the intestines where they invade cells of the gut wall and cause disease. 

Pathogens can penetrate an organism's interface with the environment  Pathogens need to enter body to cause disease- get in through organism's surface of contact (interface) with the environment e.g. nose, eyes, cuts 3 main interfaces with the environment

1. Gas exchange system - Most pathogens breathed in are trapped in mucus lining lung epithelium. These cells have a cilia that beat and move the mucus up the tranches to the mouth where its removed. But, some are still able to reach alveoli where they can invade cells and cause damage
2. Skin - if you damage your skin, pathogens on the surface can enter your bloodstream. The blood clots at the area of damage to prevent pathogens entering, but some may get in before the clot forms
3. Digestive system - Most pathogens on the food you eat containing will be killed by acidic conditions of stomach. However, some can survive and pass into the intestines where they can invade cells of the gut wall and cause disease.