What is the Anatomical Structure of Hair?
The hair is one of the skin appendages which grows out of follicles. The top of the skin is covered by dead material called keratin. Like our nails, our scalp also contains keratin, and this protective outer layer is called cuticle. The inner part of hair is called the medulla and it is surrounded by cortex layer which is the main part of hair that contains pigments.
Hair roots are located in subcutaneous tissue. Hair roots are surrounded by hair follicles. Hair cells can multiply rapidly and continue to grow by metamorphosing towards dead cells. Since hair cells multiply quickly, they push the dead cells upwards which helps hair growth. As they grow longer, they rise above the scalp. The hair follicle is surrounded by papilla that contains blood vessels, so it has crucial role in the nourishment, growth, and healthy appearance of the hair. Haircare is essential, even nutrition can affect hair.
How Does the Hair Growth Cycle Happen?
A strand of hair on the scalp grows 1.25 cm per month on average. In other words, our hair can grow up to 15 centimeters per year. The three main stages of hair growth are anagen, catagen and telogen.
Anagen phase: In this phase, which can last for 3 to 7 years, the cells in the hair follicle constantly divide and hair grows.
Catagen phase: This phase starts within the 2–5-week period after the anagen phase. The hair follicle shrinks, and the hair growth stops.
Telogen phase: After the catagen phase telogen phase starts and lasts around 2-5 months. Hairs don’t grow during the telogen phase, but they don’t usually shed.