Glossary of Hair Transplant Related Terms

Glossary of Terms

5 alpha reductase enzyme-Refers to the enzyme that converts testosterone into DHT; the hormone believed to responsible for hair loss and balding.

Alopecia areata-Temporary loss of hair, generally represented in small, coin shaped bald patches.

Alopecia Totalis- Refers to the total loss of scalp hair.

Anagen-The medical term for the active hair growth phase. Lasts up to six years.

Anagen Efluvium Refers to permanent hair loss, thought to be caused by damage to the inner hair structure.

Androgenetic Alopecia - Refers to permanent hair loss resulting from the effects of genetic conditions. This condition is most commonly referred to as male or female pattern baldness.

Androgens - Hormones produced in both males and females and are responsible for many functions including the stimulation of adrenaline. Commonly thought of as sex hormones.

Catagen Refers to the phase of hair growth where hair is shed in anticipation of new growth. This phase lasts approximately two to three weeks.

Cortical cells-Contains cigar shaped microfibril cells composed of keratin proteins.

Connective Tissue-When referred to relating to hair, provides physical support for the hair follicle.

Cortex This portion of the hair shaft is known as the middle layer hair shaft. The cortex is responsible for the overall strength of the hair and also determines the color of the hair strand as well as the texture.

Cuticle - Known as the outer layer hair shaft, this portion of the hair shaft contains layers of cells that are connected to the inner root shaft.

Dihydrotestosterone (DHT) The hormone that is believed to responsible for hair loss. It is converted from testosterone by the 5 alpha reductase enzymeis.

Erector pili Very small muscle, microscopically sized, found within the follicular unit.

Follicular unit Small grouping of anywhere between one to five hairs contained within the same anatomic unit. Follicular unit tranplants have become one of the most popular methods of hair transplantation.

Hair Bulb - Tiny white pustule at the base of the hair. The bulb, along with blood vessels, forms the root of the hair, attaching it to the scalp.

Hair cuticle- Forms the outer covering of the hair strand and has protective qualities.

Hair Follicle- Formed by skin cells bunching together. The interior of the hair follicle contains the sebaceous glands.

Hair Shaft- Protrudes just above the skin and contains older skin cells that have died as well as pigment and protein keratin.

Hair Transplantation- Type of hair loss treatment using grafts or hair plugs surgically impanted in balding areas. Hair plugs are now considered outdated with hair grafts being the more popular and natural looking form of hair transplantation.

Inner Layer Hair Shaft Also called the medulla, this layer of the shaft contain extremely small cells and is generally only seen in thick strands of hair. Some hair strands may contain and inner layer hair shaft (medulla) and some may not.

Intermediate Hair- Refers to transitional hair. Transitional/intermediate hairs are in the process of shifting from terminal hair to vellus hair and vice versa.

Keratins Proteins which form the basis of human hair.

Lanugo hair- Commonly known as womb hair. This is the hair that begins to grow on the embryo approximately five months after conception, usually very light, soft and fine. Generally shed just prior to delivery and is replaced with vellus hairs.

Medulla - Also called the inner hair shaft, this layer of the shaft contain extremely small cells and is generally only seen in thick strands of hair. Some hair strands may contain medulla and some may not.

Middle Layer Hair Shaft This portion of the hair shaft is known as the cortex. The cortex is responsible for the overall strength of the hair and also determines the color of the hair strand as well as the texture.

Outer Layer Hair Shaft- Known as the cuticle, this portion of the hair shaft contains layers of cells that are connected to the inner root shaft.

Outer Root Sheath-This component surrounds the hair follicle, covering the inner root sheath.

Papilla- The papilla is found at the base of the hair follicle. This is the primary location where the cells that form hair are produced. Blood vessels are connected to the papilla, which send necessary proteins and vitamins to the roots to nourish the hair.

Primary terminal hair- Refers to hair found on the eyebrows, eyelashes and scalp.

Propecia- Oral medication non-surgical alternative to hair transplantation. Active ingredient finasteride.

Rogaine- Topical non-surgical alternative to hair transplantation. Active ingredient minoxidil.

Sebaceous glands - Responsible for the production of oil on our skin and hair; is found inside the hair follicle.

Secondary terminal hair- Refers to hair found in the pubic areas and the facial region of men as puberty approaches.

Telogen-Refers to the phase where hair is resting or sleeping. No growth occurs during this phase. Generally, this phase lasts for about three months.

Telogen Efluvium Refers to a temporary hair loss due to changes within the structure of the hair. It is most commonly represented by Alopecia areata.

Terminal hair Refers to darker, coarser hair commonly found on the limbs and trunk of the body.

Vellus Hair- Refers to the short, usually fine and soft hair that is typically seen very faintly. Commonly referred to as down or fuzz on newborn infants. The most common sites for vellus hair on mature adults are on the forehead, ears and even the scalp, when normal scalp hairs have been lost due to the effects of balding.

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Glossary of Hair Transplant Related Terms