How do Microbes Enter Our Body?

You have learnt that microbes exist virtually everywhere,  and hence our body is constantly exposed to them. They gain access  to our body through the natural openings like our mouth, nose, urinary and reproductive passages (Fig). This can happen while we breathe contaminated  air, drink impure water or eat infected or spoiled food; They reach our lips when we  touch them with gemcarrying fingers or finger nails, when we drink from glasses or cups which have not been washed well or even while wiping the mouth with dirty and used towels. We can get infected from other persons by  contact while shaking hands, or otherwise touching their body. Germs can enter our body through urinary and reproductive passages during sexual activity.   

Our eyes get germs from infected air or dust. Each of  these natural openings leads  to a tube which  reaches other organs. Thus germs get into our body and infect our organs. The  tubes are lined with soft mucous membranes which can resist penetration only when a person  is ih a state of  gd  health. In case of common cold,  the mucous membrane itself is attacked,  and gens  sit and multiply on it. Gems are invisible invaders and it is not easy to check their entry. The major physical barrier to their entry is our skin. As mentioned earlier, a large number of  them  live on our skin and most of them are harmless. Some germs do cause boils and pimples, invade roots of hair and set up  local  infection. If  the infection is not controlled it may spread deeper under the skin. If  the skin is cut or scraped off by  injury. bacteria get under the skin. and the wound becomes septic. Insects are also  carriers of many disease germs. The blood-sucking insects on biting, puncture  the skin, and thus introduce germs into  the body. For example, the female mosquito Anopheles injects germs of malaria; worms of  filaria are also camed by  a kind of mosquitoes. Similarly,  plague and sleeping sickness are caused by  bites of fleas and a fly called the tse-tse, respectively. Many worms, such as hookworm can penetrate through the skin and enter the blood stream. Eggs of pinworm enter through the mouth by  contaminated fingers  or infected food or water. As'you know, the bite by  a mad dog is almost always fatal. This is because the dog cames germs causing rabies. Dirty and  infected syringes used  for injections can also cause disease.