Hair & Hair Follicles

papilla

a projection of connective tissue into the hair follicle and contains blood vessels that provide nutrients to the dividing cells of the matrix.

root

extends into the dermis of the skin and sometimes the hypodermis.

hairs

found all over the body with the exception of the palms, soles, lips, and parts of the external genitalia. consists of dead, keratinized epithelial cells and has two main sections.

arrector pili

a bundle of smooth muscle cells attached to the connective tissue sheath around the hair follicle. contraction moves the hair from its normal angle to a 90 degree angle with the skin surface, elevating the skin surrounding the hair shaft & causing goose bumps.

connective tissue sheath

comprised of dermal tissue & surrounds the hair follicle.

cortex & medulla

contain pigment granules that give hair its color.

hair bulb

contains the papilla of the hair and matrix.

matrix

derived from the stratum basale of the epidermis. forms new hair cells that are added to the base of the hair root.

shaft

projects the skin from the surface.

hair follicle

surrounds the hair root. formed from epidermal layers that project into the dermis.

cuticle

the layer of hair that we see. a thin layer of dead, flattened keratinized cells that overlap each other like shingles on a roof.