Coarse straight hair:
Coarse straight hair has no curls. It differs from fine straight hair by a greater diameter and a greater development of an irregularly hollow core, the medulla, which improves somewhat the insulating properties of the hair. The total bulk of hair is often impressive. It bends less readily than fine straight hair, and can be very stiff so that it is best controlled if it is kept either very long or short. Coarse straight hair is usually black and is frequently found in East and North Asians, but also occurs in many Native Americans.
