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Describe 2 ways the body prevents the entry of microorganisms.

The body has two types of defence mechanisms that protect it from the entry and then invasion of pathogens and microorganisms. The first line of defence prevents the entry of microorganisms in the body while the second line of defence destroys the pathogens that enter the body.

The first line of defence consists of skin, mucosal membranes, cilia and stomach acids. The skin covers the entire body and the pathogens can only invade it if there is a cut in the skin. The mucus is sticky and traps pathogens while cilia also trap it and then sweep it into the stomach. In the stomach, there is hydrochloric acid (HCL) that can destroy these pathogens.  The two of them are explained below in detail.

1.     Skin: The skin is tough and can act as a physical barrier. It produces antimicrobial secretion that acts as the chemical barrier. Also in tears there are digestive enzymes that can destroy bacteria on the skin. If there is a cut on the skin, then a clot develops quickly so that the pathogens do not enter through it.

2.     Nose and Trachea: The nose has mucus and has a lining of tiny hairs called cilia. The mucus is sticky and along with the pathogen it can stick within the cilia, so that they do not enter the lungs. The trachea also has mucus and ciliated cells that are in flapping motion and hence can sweep the mucus with trapped pathogens into the throat and then from there it lands into the stomach which has HCL that can kill the pathogens and microorganisms. 

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