Hair is continuously growing little organ of our body. It has a root which is placed in the lower part of the skin. From this root hair emerges out of the skin. (image of skin with hair root, like this one-)
Hair follicle (hair root) is placed in the second layer of skin. Hair over different parts of the body vary in density, thickness and length. The hair over the scalp grows longer than the hair from other body parts. The Beard hair is thicker and body hair is finer. Body hair i.e. chest and arm hair, doesn’t grow long.
There are three main types of hair based on races i.e. Asian hair, African hair and Caucacian hair (European hair). There are minor regional differences within the races also. Caucasians have the most density of hair, Asians have the thickest diameter of hair and fastest growing hair and Africans have the most curled hair over the scalp.
Root of the hair contains colour cells (Melanocytes) which are responsible for the colour of the hair. The nutrition to the root determines the thickness and shine of the hair.
Hair is dynamic, changing it’s structure from childhood to puberty to adulthood and to old age in terms of thickness and color. The hair cycle is divided in three distinct phases. 1) Anagen, 2) Catagen, 3) Telogen.
The main growing phase of hair is called Anagen phase which is a major determinant of the maximal hair length, along with the rate of hair growth. This phase lasts for 3-10 years for scalp hair. However, this phase has different time duration for different types of hair. For example: the anagen phase of eyebrow hair is 70 days while the anagen phase of the hair over the scalp is 3-10 years on an average. This is the reason why eyebrow hairs are much shorter than the hair over the scalp. An increase in the duration of anagen increases the length of the hair.
The second phase is Catagen phase which is a short transition stage that occurs at the end of the anagen phase. It signals the end of the active growth of a hair. This phase is of 2-6 weeks duration for scalp hair.
The third phase is Telogen Phase. It is the resting phase of the hair cycle. Duration of this phase is 3-4 weeks for scalp hair. After this phase, the hair root goes into the phase of Anagen again and new hair emerges from the hair follicle (hair root).
Understanding the structure of the scalp will help you to understand how safe the hair transplant procedure is. Scalp has five distinct layers - 1) Skin, 2) Subcutaneous tissue, 3) Aponeurotica, 4) loose connective tissue, 5) Pericranium. After these 5 layers, the skull bone comes and your brain is protected inside the skull safely. For hair transplant, we have to take out the hair root from the skin of the donor area and have to implant into the skin of the bald area. As all the surgical work is going on in the skin layer without affecting the deeper structures like skull bone and brain, hair transplant does not have major surgical side effects or complications.
What is a graft and follicular unit and a hair root? People are always confused between Graft (i.e. Follicular unit) and Hair Root (hair follicle). I will explain it to you in simple words. Hair root is called Hair Follicle in medical terms. These hair roots are present in a group of 2 to 5 roots over the scalp as shown in the following image. This group of hair roots is called a graft or follicular unit.
1 graft/follicular unit = 2-5 hair roots
The reasons for baldness are different for male and female. If you observe any bald male person, you will find that baldness affects only the front, mid and crown area of the scalp. It does not affect the back of the scalp and the side of the scalp area in most of the patients. For more information Click Here.
The best donor area is the back and the side of the scalp. However, if scalp hair are not sufficient in number, we can use beard hair and chest hair to implant over the bald area. One very important point to keep in mind is that only FUE technique can take out grafts from the beard and chest donor area. For more information Click Here.