Hair biology
- 1. HAIR BIOLOGY The Biology of the Hair
- 2. What is hair Hair is a simple structure that is made up of Protein filaments called Keratin. Hair acts as a barrier to foreign particles. It's an important part of appearance and creates gender identity. Hair is the only body structure that can completely renew itself without scarring.
- 4. Hair is made up of two separate structures The hair follicle: which exists below the skin. The hair shaft: which is the hair that we see.
- 5. HAIR FOLLICLE: the living part of the hair contains the germinal matrix, which is where cells produce new hairs. Contains the bulb, which is the stocking-like structure that surrounds the papilla and germinal matrix. It's fed by capillaries. The follicle is surrounded by an inner and outer sheath that protects and molds the growing hair shaft. The inner sheath follows the hair shaft and ends just before the opening of the sebaceous gland. The outer sheath continues all the way up to the sebaceous gland
- 7. HAIR SHAFT: the dead hair we can actually see. The innermost layer: This is called the medulla. Depending on the type of hair, the medulla isn't always present. The middle layer: This is called the cortex, which makes up the majority of the hair shaft. Both the medulla and the cortex contain pigmenting cells that are responsible for giving hair color. The outermost layer: This is called the cuticle, which is formed by tightly packed scales in an overlapping structure that resemble roof shingles. Many hair conditioning products are formulated to even out the cuticle by smoothing out its structure.
- 8. The growth cycle The anagen phase is the active or growth phase of the hair. Most hair is constantly growing and spends three to four years in this stage The catagen phase is a transitional stage, and 3% of all hairs are in this phase at any given time. It lasts for two to three weeks The telogen phase is the resting phase, which lasts for about three months and accounts for 10% to 15% of all hair
- 9. THE GROWTH HAIR CYCLE https://www.google.com/search?q=WHAT+IS+HAIR&sourc e=lnms&tbm=isch&sa=X&ved=0ahUKEwjUlL305_nVAhWoD 8AKHfUeAgIQ_AUICigB&biw=1600&bih=794.
- 10. REFERENCES Heather Brannon, MD. The Biology of the Hair. Available at:https://www.verywell.com/the-biology-of-hair-1068785. Updated June 24, 2017.