Sweat Gland Structure
Sweat glands, also called sudoriferous glands, are simple tubular glands found almost everywhere on our body. Each sweat gland is made up of two portions:
1. A secretory section.
2. An excretory duct.
The secretory portion is found in the dermis, the middle layer of the skin. Sometimes it’s also found in the hypodermis, the deepest layer of our skin.
The secretory portion of a sweat gland is a twisted and coiled tube that has an opening at its very top. It is in the coiled secretory portion of the sweat gland where the sweat is actually produced. The excretory duct moves from the secretion portion, through the dermis, and into the topmost layer of the skin, the epidermis, where it opens up at the surface of our skin.
Eccrine Glands
The most numerous types of sweat glands in our skin, found almost everywhere on the body, are called eccrine glands. These are the true sweat glands in the sense of helping to regulate body temperature. In other words, sweating causes the loss of body heat and thus cools us down on a hot day or when performing strenuous exercise. This is because as the water in sweat evaporates, it takes body heat with it.
Apocrine Glands
The other kind of sweat glands are known as apocrine glands. The apocrine glands are found in places like the armpits, scrotum, anus, and labia majora. They are typically larger than eccrine glands and their ducts tend to open into hair follicles instead of hairless areas of skin.
These glands, unlike the eccrine glands, serve virtually no role in the regulation of body temperature. These are also the glands largely responsible for body smells, as their excretions are converted by skin bacteria into various chemicals we associated with body odor.
Unlike eccrine glands, the exact function of apocrine glands is unknown and debated. We do know they are activated during times of stress, pain, and sexual foreplay but for what reasons is yet to be made clear.
Human Skin
Cross sectional image of skin showing a sweat gland and a sebaceous gland.