Glands of Skin
Within the dermis are three kinds of glands: The eccrine sweat glands, the apocrine sweat glands and the sebaceous or oil glands. The sebaceous glands open into the hair follicles, and together these form the pilosebaceous apparatus. Although apocrine gland ducts sometimes open directly into the epidermis, most of them also open into the hair follicle. Eccrine sweat glands develop independently of hair follicles and their ducts lead directly into the dermis.
There are more eccrine sweat glands in man than in other animal, about three million total. They are most dense on the palms of the hands and soles of the feet, and then, in decreasing order, in the forehead, cheeks, trunk, arms and legs. Their small openings are invisible.
The eccrine sweat glands, along with the dermal blood vessels, play a vital role in regulating body temperature. When the body is hot, the eccrine glands release a thin, watery solution – sweat – onto the skin surface, which evaporates and cools the skin. The coiled lower portion of an eccrine sweat gland, which lies in the dermis, is the part that secretes fluid. Making its way like a corkscrew thorough the epidermis, the upper end opens onto the skin surface.
Working at maximum exertion on a very hot day, you may produce more than two quarts of sweat in an hour. People who lack normally developed sweat glands are vulnerable to heat stroke. We perspire for other reasons besides heat, the most important of which is emotional stress – pain, anxiety, fear, anger. Sweat caused by such stress occurs mainly on the palms, soles and armpits. Eating spicy foods also makes some people’s faces sweat, a phenomenon known as “gustatory sweating.”
The apocrine glands are formed before birth and appear just above the budding sebaceous glands as outgrowths of the hair follicles. They are present over the entire surface of the body at birth. Most of them disappear later, however, remaining only in certain areas: under the arms, around the nipples and in the lower abdomen and genital regions. The glands are small until puberty, when they enlarge and begin to secrete. They shrink again as the body ages.
The apocrine glands are distributed over the entire bodies of such lower mammals as rats and mice, and function as scent glands for sexual attraction and protection. Apocrine glands apparently perform no useful function in humans; they may even serve as sites of disease and are the source of unpleasant body odor. Mexican pharmacy viagra. Fresh sweat is odorless; the odor results from the decomposition of sweat by bacteria present in apocrine glands.
Sebaceous or oil glands grow from the hair follicles. They are in plentiful supply over the entire body surface except for the soles and backs of the feet and the palms of the hands. The largest and greatest number are on the face, scalp, upper chest and back.
Sebaceous glands produce and secrete sebum, a semi liquid mixture of lipid (fat) and cellular debris. Sebum spreads over the surface of the hair and outer layer of the skin and acts as a natural lubricant that locks moisture into the skin. Sebaceous glands have the reputation of being the sites where acne develops.
Sebum production depends on the presence of male hormones called androgens. The sebaceous glands of newborns are active because of androgens they receive from the mother through the placenta. Shortly after birth, those glands stop functioning and remain at rest until puberty. During and after puberty, the testes in males and the ovaries and adrenal glands in females secrete androgens.
How your skin functions efficiently and smoothly depends on many factors of your health: diet, physical condition and emotional well – being. It’s all part of the same system