- BY Anil Abraham |
- September 18, 2017 |
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Hair is often referred to as the crowning glory and has been praised as an important attribute of beauty by poets like Kalidasa. References to the black waist length hair of Shakuntala or Damayanti are common in literature. Draupadi left her hair loose until her vow was fulfilled. Even for men hair is often considered a sign of virility and good looks. Samson even lost his hair when his hair was chopped off by Delilah. In the animal species the mane of the lion or the attractive feathers of birds like the peacock underline the fact that hair and its modifications have long been a socially accepted part of interaction between the sexes. The hair can tell you about the typeof person in front of you. A sheved head can mean a bereavement in the family or recent pilgrimage to Tirupati or Vailankanni. Uncut hair in a male wearing a turban can help to identify a person as a Sikh or may even make people the focus of unwanted attention as happened in the US after the 9/11 tragedy. A punk cut with purple or pink tints may signify trendiness or rebellion whereas a military cut just before an interview may help to convey to the interview board that you are reliable and disciplined.. The hair can be your method of making a first impression and combing the hair in a mirror is probably what every person does before leaving the house.
TYPES OF HAIR
There are three types of hair (Table 1). Thick, pigmented hairs are called terminal hairs. Terminal hairs on the top of the scalp and in the beard, axillary and pubic areas are influenced by androgens. Androgens are important in regulating hair growth. At puberty, androgens increase the size of follicles in the beard, chest and limbs and decrease the size of follicles in the bitemporal region, which reshapes the hairline in men and many women.
Lanugo hairs are the fine hairs found on the fetus; similar fine hairs found on the adult face and body are called vellus hairs. Vellus hair is short, fine, relatively nonpigmented and covers much of the body. Hair on the rest of the body is independent of androgens.
Table 1 : TYPES OF HAIR
Terminal Hair : Thick Pigmented : Head, Beard Vellus Hair : Fine, Light colored Eg : Body
Lanugo Hair : Fine, Light colored : Fetus
HAIR GROWTH CYCLE
Each hair follicle perpetually foes through three stages in the hair growth cycle: catagen (transitional phase), telogen (resting phase), and anagen (growing phase) (Fig 2). Approximately 90% to 95% of hairs are in the anagen phase, and 5% to 10% are in the telogen phase. Up to 10 telogen hairs are lost each day from the head, and about the same number of follicles enter anagen. The duration of anagen determines the length of hair, and the volume of the hair bulb determines the diameter (Table 2).