Hair Anatomy

Written by Dr. Griffin

Hair-anatomy. Simplified diagram of the skin and hair

This is a simplified diagram of the skin and hair. As it illustrates, there are two main sections of the hair anatomy—the shaft and the follicle—as well as an attached sebaceous gland.

Hair Anatomy - Diagram B

Diagram B – Hair Anatomy

Learn About the Structure and Composition of Hair from the Philadelphia Area’s Dr. Thomas Griffin

Hair plays an essential role in society and is seen as symbol of identity, health, attractiveness, youth, and virility for men and women alike. But have you ever wondered what your hair is actually made of? Hair anatomy may seem simple, with the strands on your head and body being nothing more than colored keratin, but there is much more to it going on below the skin. The team at the Griffin Hair Restoration Center of Philadelphia is highly knowledgeable on hair anatomy. Philadelphia-area patients often seek advice from Dr. Thomas Griffin on how to take care of their hair properly to keep it healthy and well maintained. Understanding hair anatomy, from the visible shaft to the lower follicle, is important, as it helps us understand what causes hair loss and how best to prevent and treat it.

Explore advanced treatments for hair loss and learn all about hair anatomy from the Philadelphia-based team at The Griffin Hair Restoration Center of Philadelphia. Call (215) 561-9100 or submit a contact form to request a consultation.

Hair Anatomy Details: What is Hair Made Of?

Each person has around 100,000 hairs on their head, but some of these strands are lost each day. When everything is working as it should, the hairs that fall out are lost each day. When everything is working as it should, the hairs that fall out are constantly replaced, thanks to the normal hair cycle.

Hair anatomy consists of two main components: the hair root and the shaft. The hair that is visible above the surface of your skin anywhere on your body is actually made up of cells that are no longer alive. These are called the shafts of the hair. The part of the hair anatomy that you can’t see below the surface is made up of living cells.

The hair bulb in the middle layer of skin is called the root of the hair. It is where new hairs are created and nutrients are delivered to the cells. Each part of the hair anatomy works together to support the hair growth cycle.

Hair Anatomy: The Follicle

Hair follicles are an essential part of hair anatomy. Not only do they generate the hair strands, but they keep the hair anchored to your scalp.

The follicle is composed of several parts that perform various functions. As can be seen in diagram B, the dermal papilla is the base of the hair follicle, containing capillaries that feed the hair cells with nutrients passed through the hair bulb. This hair bulb is the living part of the hair, fed by the papilla, and these living cells grow and multiply at a very quick rate. The cells divide every 23 to 72 hours, which makes them the fastest multiplying cells in the body. Their multiplication spurs the actual growth of hair.

The remainder of the hair anatomy is composed of an inner and outer sheath, both of which serve to form and shield the growing hair shaft. The inner shaft ends at the sebaceous gland, while the outer sheath continues up the shaft and attaches to the arrector pili muscle. The contractions of this muscle are what cause the hair to stand up on end when the body is cold, nervous, or excited.

Hair appears in many different colors—such as black, brown, blond, or red—due to the pigment cells that produce melanin in the hair follicle.

Hair Anatomy: The Sebaceous Gland

The sebaceous gland is an exocrine gland connected to the mid portion of the follicle. It secretes sebum, an oily or waxy substance that is important to the skin because it provides natural lubrication and waterproofing. More than one sebaceous gland may be attached to a single hair follicle, and the sebum is delivered to the surface of the skin by traveling up the hair itself. The number of glands and the amount of sebum they produce are hereditary, though generally more sebum is produced after puberty and decreases steadily with age.

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Hair Anatomy: Hair Shaft

The hair shaft is the visible component of hair anatomy that people generally think of as “hair.” It is composed of many layers of a protein called keratin, which is a very tough protein. The cells are dead, which is why hair can be safely cut and styled without pain.

The keratin in a hair shaft is naturally arranged in three layers from the innermost medulla to the cortex to the outermost cuticle. As the outermost layer, the cuticle is what is typically treated with hair conditioning, repairing, and strengthening treatments.

Find out more about prevention, diagnosis, and treatment for hair loss from a team knowledgeable in hair anatomy in Philadelphia. Contact The Griffin Hair Restoration Center of Philadelphia by calling (215) 561-9100, or submit a contact form to request a consultation.