Acne is the most common skin condition in the United States, affecting up to 50 million Americans annually. 1 There are different types of acne (blackheads, whiteheads, pimples, acne cysts or nodules) ...

A bundle of neurones is called a nerve. There are three main types of neurone: sensory, motor and relay. They have some features in common: A long fibre (axon) which is insulated by a fatty ...