Hair Structure and Hair types
Stucture of hair in skin:
It consists of 5 layers, these layers are:
- Beneath skin
- loose skin (Aponeursisi)
- loose tissue layer
- outer bone layer (Percranium)
While the outermost layer of skin is the thickest on the nape of the neck it is the thinnest above the forehead area. Thickness changes approximately 8-3 mm. The skin layer has hair, oil glands and sweat glands.
The Beneath skin layer has more fatty tissue. Gaining and losing weight doesn't change fatty tissue of the hair. Fibrous is the healthy layer of skin, it makes it more resistant. Verticle veins and nerves beneathe the skin......
The third layer is muscle and a firm layer.
The fourth layer is a loose layer. This layer is easily separated from the 3 other layers.
The layer under that is the layer that is firmly stuck to the bone. It provides bone growth, bone thickness and rejuvination.
- Fat tissue
- Blood vessels - arteries
Hair is made up of strong structural protein called keratin. The outer skin coat and the nail shows a similiarity.
Hair consists of 3 layers
inner layer or medula, this is only seen in thick hair.
middle layer called the cortex, it gives color and strenght
outer layer called the cuticle is thin, no color and protects the cortex.
The part of the hair under skin is called the root. Under the hair root is a layer which is rich of blood vessels. (dermal pailla) Hair is nourished with this layer. It has receptors, dermal papilla male hormones and androgens. Genetically these receptors, androgens, cause hair loss. The hair follicle gets thinner and smaller which makes the hair thin and fair.
Hair growth stages:
Hair follicles progress stages of repetition and every hair follicle is in its own different stage.
1. Anagen Phase: growth phase. Hair is 84% is in this phase. May last up to 2-6 years. Hair may grow a length of 10 cm. a year.
2. Catagen phase: Transition phase. After the anagen phase the hair will shrink up to 6 times its size, this period is about 1-3 weeks. The dermal papilla is damaged. 1-2% hair is in this phase.
3.Telogen phase: Resting phase. This phase usually lasts 2-3 months. Hair will not grow but as long as the there is dermal papilla the hair will stay stranded as a follicle. 13% of the hair is in this phase. After this phase the anagen phase will start again. The bond between the dermal papilla and the hair follicle will again begin another cycle and new hair will start to grow. If the older hair hasnt fallen out the new hair will push out and start growing.
Is short hair (fuzz)which is 1-2 cm. in length. Insufficent color substance in other words pigments are scarce therefore the fuzz is colorless. It does not have oil glands in its roots or medulla layer. This type of fine and soft hair does not influence the esthetic look.
2. Terminal hair.
This type of hair is normal structured hair. This type of thick hair is on the head and body and is considered terminal hair. It has dark pigment particules and the medulla is in the middle with thick terminal hair.
this type of hair has both vellus and terminal hair characteristics. Has a medulla, has some pigment but less than terminal hair. hair loss may occur for some people because they do not show change like terminal hair and become vellus hair.