Explain how the human body might protect itself from microorganisms.

There are two different types of microorganism - bacteria and viruses. The human body is covered in bacteria, the majority of which is good bacteria and they won't cause any harm. The rest are pathogens which are able to cause damage if they infect the human body. The human skin is a type of defense, it keeps harmful microorganisms outside of the body and also insulates it. The cilia and mucus in the trachea and lungs removes any inhaled microorganisms along with debris such as dust and other fine particles. The acid in the stomach can also kill the pathogens from any food consumed. If the viruses or the pathogens manage to infect the body, the neutrophils and mast cells increase the blood flow starting the immune response. The lymph nodes send out lymphocytes to destroy the foreign microorganisms, by engulfing them. Certain immune cells such as T and B cells have memory of every microorganism to infect the body so if the same type of microorganisms is every to be encountered they know how to remove it more efficiently.