What causes sickness?

Question

I know infections, 'bugs' etc - but I'm after a more scientific answer. Thanks...

Answer 1

There can't be a full answer to your question - it would be volumes long! Sickness can be caused by a vast multitude of factors.

Viruses for example cannot replicate by themselves. They hijack cells in your body (which have replication mechanisms) and use them to multiply their own DNA/RNA. Think of it as feeding them new 'blueprints'. In most cases the end result is the cell dying, releasing all the new little viruses in made (which in turn find new cells).

Bacteria can cause sickness in a number of ways. They can feed off your organs (yupp, you are their food source), get their base materials to replicate like that, then multiply. They produce toxins which weaken your body, allowing them to hamper your immune system so they can replicate more...they can do a lot of different things. Bacteria are extremely diverse have a very wide variety of functions.

There are genetic diseases. These are natural weaknesses that have evaded natural selection. Cancer for example, usually occurs after your reproductive age. Therefore, even though it will kill you young, it's after you've passed on the defective anti-cancer genes for it to a new generation. (cancer is prevented by 7 specific genes...if I remember my course correctly :). But not all may be functioning. If you have all 7 intact you can likely rest assured you will never have cancer. If some are inactive either because you inherited flawed genes or a process called DNA methylation, the chances of you getting cancer rise).

Other genetic diseases can function in a similar manner. Other ways are by being genetically "recessive". I.e. you won't be affected unless you have two defective genes (not only genes...there are repetitive strands of DNA, etc...but that's getting in too deep). So, if you only have one defective copy of a gene, you will be fine. But should two carriers procreate they have a chance of giving their offspring two defective gene copies and hence the disease.

Sickness can be caused by environmental factors, chemicals, protozoa (Sleeping sickness is caused by Trypanosoma brucei, a parasitic protozoan), other parasites, incorrect chromosomal replication....the list goes on!

That was just the tip of the iceberg - as I said there are so many causes for sickness that they simply can't all be mentioned..

Answer 2

if you think of the human body like a machine, there are lots of different systems working independently and with each other. eg, you mouth. nose, oesophagus (air pipe) lungs and diaphragm (the muscle that expands and contracts the lungs), all work together to get air into your lungs, once the air is in your lungs the oxygen touching the walls of your lungs passes thru teeny (i know thats not a scientific word but bear with me) tiny holes into your bloodstream, where it is carried to every single muscle and organ, in your body, every minute of every day of you life this is happening, if you lose the oxygen supply to your brain for 10min you will suffer permanent brain damage or even die. and thats just your circulatory system, there's also all the jobs your organs do, eg your kidneys filter and clean you blood then put it back into the bloodstream, then they put the waste products from your blood into urine and the urine removes it from your body, like a garbage truck. your liver makes all the chemicals for your body needs to keep working, i wont go on anymore, the point is that when anything, be it injury, infection, cancer, bugs, whatever stops a part or system of your body from working properly that is sickness.

Answer 3

All sicknes is caused by one of two things,lack of proper nutrution and stress,most of the people of the world do not have access to proper food food and water,and those that do eat large amounts of junkfood,the proof is in the pudding,the longest livers in the world are the Hunza people in Georgia,they rarely are ill and live to an average on 95 years,they live on vegatables,steamed or raw,small amounts of chicken,clean water and a lot of fruit,mainly cherries and apricots

Answer 4

Not sure if I can give a scientific answer but, I know that out of date food, migraines, eating too much, alcohol, viruses all cause sickness...

Answer 5

Humans ....overpopulation .....STD ....You never hear of animals with STD