HAIR

HAIR

• Any of the fine thread like strands growing from the skin of mammals,esp. from human head.
• Hair is actually grow from dermis layer and they are mainly a protein filaments.
• Each strand of hair is made up of the medulla, cortex, and cuticle.
• The innermost region, is not always present and is an open, unstructured  region.
• The highly structural and organized cortex, or second of three layers of the hair, is the primary source of mechanical strength and water up take.
• The cortex contain melanin, which colors the fiber based on the number, distribution and types of melanin granules.
• The shape of the follicle determines the shape of the cortex, and the shape of the fiber is related to how straight or curly the hair is.

HAIR GROWTH CYCLES:

There are total 3 cycles for hair growth, they are as below:

1. Anagen(grow phase): Most hair is growing at any given time.Each hair spends several years in this phase.
2. Catagen phase( transitional phase): Over a few weeks, hair growth slows and the hair follicle shrinks.
3. Telogen( resting phase): Over months, hair growth stops and the old hair detaches from the hair follicle. A new hair begins the growth phase, pushing the old hair out.

OTHER FACTS ABOUT HAIR:

• Everyday the average person loses 60-100 strands of hair. And this is happen because of the season, pregnancy illness, diet and age.
• Hair only grows 0.3 - 0.5 millimeters each day. Or about 1 cm every month. so this means that it can keep this life diary for a long time- for a month or even year.
• The average human has 100,000 hair follicles or above.
• The life span of human hair is 3-7 years.