Structure of Hair and Hair growth cycle

Introduction, Structure of hair and Hair growth cycle

1. STRUCTURE OF HAIR AND HAIR GROWTH CYCLE UNDER THE GUIDANCE OF Kamal Deka Assistant Professor SUBMITTED BY Debasish Deka M.Pharm 2 nd Sem FACULTY OF PHARMACEUTICAL SCIENCE, ADTU

2. INTRODUCTION STRUCTURE OF HAIR HAIR GROWTH CYCLE CONTENTS

3. Hair is made from strong structural protein named as Kerotin . This is of exactly the same protein from which the nail and outer skin layer is comprised. INTRODUCTION:

4. There are mainly 3 glands are involve in hair. The epidermis is known as hair shaft. The hair shaft is comprised of three layers: cuticle, cortex and medulla. The innermost layer (known as the medulla) only present in large thick hairs The middle layer ( known as the cortex) which gives the hair its strength, texture and colour . The outermost layer ( known as the cuticle) a thin and colourless layer that is defensively to prevent damage to the hair’s inner structure and to control water content of hair fibre . STRUCTURE OF HAIR

5. The dermal papilla contains the blood supply and nerves that produce nutrient for the hair. These vital nutrients are needes in order for hair to grow. The dermal papila is shaped smilar to a cone and sits inside the hair bulb.

6. The oil glands of the skin are called sebaceous glands. These glands are connected to the hair follicle and secret sebum, an oily substance that lubricates the hair. Structure of Hair

7. HAIR GROWTH CYCLE Hair growth cycle comprises of 4 phases. These are

8. 1) Anagen phase (Growing phase) - The growing phase last 2-7 years and determine the length of hair. Hair grows arround half an inch a month and faster in summer than winter. The anagen phase last and average of 3-5 years, a full length hair averages 18-30 inches. The anagen phase is generally longer in asian and last as much as 7 years with hair being able to grow to one meter.

9. 2) Catagen ( Transition phase)- This is the transitional phase that last about 10 days. The hair folecule shrink and detouches from the dermal capillla .

10. 3) Talogen phase (Resting phase)- This is the resting phase which are less around 3 month. Arround 10- 15 % of hair are in this phase. The old hair is resting, a new hair begins the growth phase. Lastly hair enters the alogen phase, hair is release and false out.

11. The follicle that remain inactive for 3 months the whole process is repeated. During the talogen phase the follicle remains dorement for 1- 4 months. Each hair follicle is independent and grows through the growth cycle at different times, otherwisw all hair will fall out at once. During the talogen phase the follicle remains dorement for 1-4 months. 1-50 % of the hair are in this phase growth at any event time. At some point the follicle begin to grow again, softening the ancure point and hair base will break free from the root and the hair will be shed. Within 2 weeks new hair shaft will begin to emarge once the tallogen phase is complete.

12. 4) Exogen phase- This is the part of resting phase where the old hair falls and new hair continueous to grow. The thickness, texture and shape of the hair is determine in this stage.

13. The following factors create an interruption of the normal cycle causing excessive hair loss:- Stress Change in diet Drugs Illness Post pregnancy

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