The causes of disease in humans
A disease is an abnormal or particular condition that can affect parts of an organism, or all of it. A disease can be due to a pathogen such as a bacterium, a fungus or a virus or it could be due to our genetics, or even our lifestyle choices. Throughout this essay I will discuss these various ways. A microorganism is a single or multicellular organism which is the most popular cause of disease. There are many type of microorganisms such as a virus, bacterium, prion, fungus or protozoan and these enter the body either through breathing them in through your nose, in through your mouth as food and into your digestive system or through a break in the skin such as a simple cut. These pathogens cause disease in our body by releasing toxins which can damage our cells. An example of a toxin is Cholera. Cholera is a bacteria that is taken in by us humans when we eat or drink foods that are contaminated. This then produces a toxin which in itself is a protein and this protein will then bind to the channels of the epithelial cells in the small intestine. This binding causes some of the protein channels to stay open and therefore chloride ions can then move from the epithelial cell into the lumen of the small intestine via diffusion. This then means that the water potential in the epithelial cells in higher than that of the lumen and so water moves from these cells and into the lumen via osmosis. Water is lost because of this and this in itself causes dehydration and diarrhoea which are the symptoms of Cholera. Another disease which is caused by a pathogen is that known as Tuberculosis. Mycobacterium Tuberculosis is one of the main types of tuberculosis. This bacteria is transmitted in droplets and these droplets are taken in through breathing and then are engulfed by phagocytes. These bacteria are then encased in tubercle where they will be dormant and not replicating in primary TB. If immunosuppression occurs then the bacteria is...
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