Warns you of uninvited guests
Mosquitoes, bugs, and other parasites tease a sense which scientists recently began to map out: the sense of itch. When parasites penetrate your skin, they use special enzymes known as proteases. They make the body’s white blood cells produce the histamine neurotransmitter, which activates nerve cells in the skin. The result is a pricking itch in the place in which the parasite has taken hold. In this way, the sense of itch warns the brain of invading enemies. The sense can also be activated by other foreign bodies such as pollen.