Sphygmomanometer

The force blood exerts against the walls of the arteries. Optimal blood pressure is less than 120/80 mm Hg.

A ring of muscle that surrounds an opening and can be contracted to close the opening. For example, the muscles found at the anus and the opening of the bladder are sphincters.

A condition which affects the unborn baby in the early stages of pregnancy. Spina bifida causes damage to the spinal cord and nerves.