The membrane lining the eyelids and covering the eyeball.

A feeling of sickness in the stomach, sometimes followed by the urge to vomit.

The back of the head.

A fatal, if untreated, viral disease of mammals that's spread to humans by the bite of infected animal.

A system of assigning priorities of medical treatment based on urgency, severity of injury and chance for survival.

The part of the body between the chest and pelvis.

A wound caused by scraping the skin. A "skinned knee" is a common example.

To take in substances through the skin or mucous membranes.

The process of getting used to a new climate or altitude.

An abnormal condition in the body in which excessive acid lowers the pH of the blood and body tissues.