Hair

Hair - Overview

Hair is a keratinized gross fibre structure that grows out of the follicle. Hair varies in length and texture. The long, coarser ones are the terminal hairs, the shorter, softer are vellus hairs

Hair Follicle

Hair Follicles are organs that represents the invagninated epithelium continuous with surface epidermis. The follicle diameter is greatest at the base known as Bulb where it forms a egg shaped structure to enclose the connective tissue known as dermal papillae. Moving towards the epidermis the follicle is further dividied into Supra Bulbar area, Isthmus and Infundibulum.

Bulb of the Hair

Bulb of the hair is egg shaped structure completely filled with Dermal Papillae and the lowest portion also know as matrix ( Rich in melanocytes)

Outer Root Sheath

Outer root sheath of hair is continous multilayered structure of epidermis into the hair follicle. The outer root sheath forms a bulge which contains proliferating cells with stem cells characterstics.

Inner Root Sheath

Inner root sheath of hair immediately surrounds hair shaft and play important role in maintaining growth and integrity of hair. It is divided into Henle's Layer, Huxley Layer and Cuticle

Hair Shaft

Shaft of the hair is composed of cuticle on the outside and a cortex. Medulla represents the core of hair shaft. The cells of cuticle of hair shaft bind to the inner root shaft firmly anchoring the hair within the hair follicle

Fibrous Root Sheath

Fibrous root sheath is the Outermost layer of shaft of the hair and is compsed of collagenous fibres.

Dermal Papillae

Dermal Papillae of the hair is the connective tissue element enclosed by the bulb of the hair follicle. It is richly vascularised more in terminal hairs lesser in smaller ones and not at all in vellus hairs.

Hair Matrix

Matrix of the hair is the germination center of the follicle in lowest part of the hair bulb where cells are mitotically active

Glassy membrane

Glassy membrane of the hair is a non cellular partition tha separates the outer root sheath from connective tissue sheath