Those glands in the armpit, areola , labia majora and anal region are apocrine glands. Apocrine secretions are those where the apical region of the secreting cells is lost with the secretion. This type of sweat contains protein and carbohydrates that when acted upon by bacteria on the skin take on an odor. Apocrine sweat glands empty into hair follicles while eccrine glands open at the skin surface. All eccrine glands do not function all the time but they respond quickly to heat stress.
Aldosterone increases the reabsorption of sodium from sweat.
Regulatory heat exchange is accomplished by the action of the eccrine sweat glands and the cutaneous blood vessel network. As the liquid sweat evaporates and cools the skin the cutaneous blood vessels dilate or constrict to remove or conserve heat. A central nervous system thermostat in the hypothalamus regulates the function of the eccrine glands and the cutaneous vasculature. Heat is the primary stimulus to the eccrine glands but other stimuli such as nervousness or eating spicy foods can cause sweating. Acclimation to heat in the environment is required in order for the body to function well.