Home / Hair Loss Articles / FAQs / The Growth and Loss of Hair The Growth and Loss of Hair A series of articles explaining the growth/loss cycles of hair in detail. Introduction Hair provides no vital function for humans, but its psychological effect is nearly immeasurable. Luxurious scalp hair expresses femininity for women and masculinity for men. The lack of scalp hair or the presence of excessive facial or body hair is often as distressing to females as the loss of beard and body hair is to …Continue Reading The Growth and Development of Hair Hair grows from primary follicles, which are formed by the differentiation of cells in the embryonic epidermis, and further growth causes the hair to become embedded in the dermis (Figure 1). The hair papilla is formed from mesodermal cells. Completion of the terminal pilosebaceous unit requires (1) a vascular network, (2) nerve tissues to surround …Continue Reading Cortical Cells Cortex cells come from the concentric ring of germ cells localized in the bulb immediately above the apex of the papilla (Figure 3). Their successive keratinization occurs in the keratinization zone (Figure 4). In the lower segment of the keratinization zone, these spindle- shaped cells produce cytoplasmic filaments that are parallel with both the long axis of the cell and …Continue Reading Connective-Tissue Hair Sheath The connective-tissue hair sheath is an important physical support of the hair follicle. In the follicle of anagen hair the structure of the upper half of the connective-tissue sheath differs from that of the lower halt, which changes during the growth cycle. Between the epidermis and the sebaceous-gland layer fine collagenous fibers are arranged longitudinally around the upper half of …Continue Reading Regulation of Hair Growth Hair growth is regulated by several factors. The influence of innervation on the growth of hair has been studied in animals, and the experimental methods that were used involve total denervation, sympathetic denervation, and excision in follicle transplantation. Experience in hair growth in humans originated with auto- grafts during hair transplantation. Here, the excision of tissue severs its innervation. In …Continue Reading Add Comment Register Name (required) Mail (will not be published) (required) Website Leave a Comment Cancel reply You must be logged in to post a comment.