Sweat glands occur in nearly all regions of the skin, but are most numerous in the palms and soles. Each gland consists of a tiny tube that originates as a ball-shaped coil in the dermis or subcutaneous layer. The coiled portion of the gland is closed at the end and is lined with sweat-secreting epithelial cells.
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| Sweat Glands |
Some sweat glands, the apocrine glands, respond to emotional stress.
Apocrine secretions typically have odors, and the glands are considered to be scent glands. They are responsible for some skin regions becoming moist when a person is emotionally upset or uneasy. These glands are most numerous in the armpits and groin and are usually connected with hair follicles. They also become active when a person is sexually stimulated.
Other sweat glands, the eccrine glands, respond primarily to elevated body temperatures due to environmental heat or physical exercise. These glands are common on the forehead, neck, and back, where they produce profuse sweating on hot days and during physical exertion.
The fluid secreted by these glands is carried upward by a tubular part that opens at the surface as a pore. Although it is mostly water, this fluid contains small quantities of salts and certain wastes, such as urea and uric acid.
Thus, the secretion of sweat is, to a limited degree, an excretory function. With advancing age, there is a reduction in sweat gland activity, and in the very old, sweat glands may be replaced by fibrous tissues.
Similarly, there is a decrease in sebaceous gland activity with age, so that the skin of elderly persons tends to be dry and lack oils
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