HAIR

Did you know?

 

Our hair is made of...

Protein: 80% ~ 90%

Water: 10% ~ 15%

Lipids: 1% ~ 8%

Melanin: 2% ~ 3%

Other: 0.6% ~ 0.8%

   We are all familiar with hair. It grows on the surface of our skin. It has been continuously growing since the very day we were born, even before being born at all.

   Hair is mostly made of a protein called Keratin. This protein is the main structural material for humans, most notable for

building human skin and nails. 

   Melanin is the natural pigment that gives color to hair, and also to our skin.

   

This image shows a highly magnified strand of human hair.

As we can see, it is built by continuously adding layers on top of

other layers.

    

magnified human hair

   This image shows the cycle of hair growth.

   The 3 phase can be divided as:

1. Anagen (growth) 2-6 years

2. Catagen (cessation) ~2 weeks

3. Telogen (rest) 1-4 months

   

   As the diagram shows, the hair is held by a root inside our skin (anagen). When hair falls off, the thin connective tissue between the strand of hair and the root is broken (catagen). After the hair falls off and a period of resting (telogen), the root attaches to the skin layer and a new hair grows (anagen).

   

   What determines which phase our hair enters in this cycle is the number of dermal papilla (DP) cells.

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