folliikulid

Folliikulid, often referred to as hair follicles, are complex microscopic organs found in the skin of mammals, including humans. They are responsible for producing hair. Each follicle is a small, tube-like invagination of the epidermis that extends down into the dermis. At the base of the follicle is a bulb, which contains a dermal papilla made of connective tissue and blood vessels that nourish the growing hair. Encasing this papilla is a matrix of actively dividing cells that form the hair shaft.

The hair follicle goes through a cycle of growth and rest. The active growth phase, known as anagen, can last for several years, during which the hair grows continuously. This is followed by a brief transition phase called catagen, where the follicle shrinks. Finally, the resting phase, telogen, occurs, during which the hair stops growing and eventually detaches from the follicle. A new hair then begins to grow, starting the cycle anew.

Various factors can influence the health and function of hair follicles, including genetics, hormones, nutrition, and environmental factors. Conditions such as alopecia (hair loss) can result from disruptions to the hair follicle cycle. The sebaceous gland, which produces oil (sebum) to lubricate the hair and skin, is typically associated with each hair follicle. Understanding the structure and function of these follicles is crucial in dermatology and trichology.