HEAR

HAIR

Function: production and growth of the hair

Composition:

External (outer) root sheath - downgrowth of stratum germinativum of the epidermis with matrix cells (keratinocytes) and melanocytes
Internal root sheath - consists of Henle's layer, Huxley's layer, and cuticle with keratinized cells
Connective tissue sheath to which the arrector pili muscle is attached

Function: regulation of body temperature

Composition:

cuticle - the overlapping cells that lose their nuclei, and become filled with keratin
cortex - constitute the most of the hear shaft as a thick cylinder, the cells become keratinized
medulla - the centrally located axis of the hear shaft