Hair Biology

By | September 24, 2014

Hair is a very important attribute to most people around the world. It affects the appearance of both men and women and often designates a person’s gender identity. There is a lot going on within the structure that many of us do not know about, but learning a bit about the mop on the top of our head can help us to take better care of and appreciate this renewable body structure. Starting from the root/follicle we shall here describe each part of a strand in detail.

follicleThe Follicle

The follicle is the structure that forms the living part of the hair. Hair forms in a shape similar to a stocking and has several layers with different jobs. Scientists call the living part  the papilla and the capillaries feed it. The bulb surrounds and protects the papilla and has cells that divide every one to three days.

Inner and Outer Sheath

Two sheaths, the inner and outer sheath, surround the follicle. The inner sheath surrounds the shaft and ends below the sebaceous gland. This gland helps condition the strand. The outer sheath forms all the way up to the gland. A muscle is attached to this layer that can cause the strand to stand on end when a person becomes alarmed or cold.

The Shaft

shaftThe shaft is the part  that makes up the visible hair on a person’s head. Each shaft has three layers, all of which consist of dead, hard protein called keratin. The three layers have earned the names the medulla, cortex and cuticle. The medulla and cortex are the layers where pigment cells give the hair its colour.

Hair is an interesting and unique part of the body of humans the world over. It is completely renewable and can be cut or removed with no pain or scarring. Scientists today continue to learn more about it and how to care for it.

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