The apocrine glands should not be confused with the sweat glands, from which they differ in many respects. First of all, the apocrine glands are always associated with a hair follicle and also have a different localization compared to those responsible for the production of sweat.
While the secretion of the sweat glands is particularly fluid and transparent, that of the apocrine glands is viscous, milky and easily smelly. If this secretion is not completely removed or diluted by sweat, it even solidifies.
Finally, the secretory activity of the apocrine glands is discontinuous and extremely modest, especially when compared with that of the sweat glands. Despite its larger size, even when it is strongly stimulated, an apocrine gland still produces a reduced secretory volume.
As the name suggests, the secretion mechanism of these anatomical structures is apocrine. It is, in essence, a particular secretory modality, which consists in the loss of the cellular apex and in its expulsion together with the secretion.
The apocrine glands located at the skin level are stimulated by sympathetic adrenergic nerve fibers, in turn activated in response to stress and to emotional or painful stimuli.
The apocrine glands remain inactive until the time of puberty, when they respond positively to the "hormonal storm" that characterizes this delicate moment of life. The apocrine glands are numerically superior in women, where their activity is influenced by numerous factors; if on the one hand they are more active in the days preceding menstruation, on the other they reduce their secretion during pregnancy and after menopause.
The female apocrine glands are more numerous but less active than the male ones. In men, due to a greater skin bacterial flora, their secretion is degraded more easily. For this reason, generally, the man has a more unpleasant smell than the female one.
The apocrine secretion contains pheromones, so it is also attributed a function of sexual recall. Human beings, however, are not very sensitive to such odorific stimuli, especially since they have learned to mask them through frequent washing, perfumes and various deodorants.
In the human species the apocrine glands have no thermoregulatory function, contrary to what happens for other animals (for example horses).
Bromhidrosis
This term indicates a condition characterized by abundant sweating and bad smell. The main cause of bromidrosis is the increased decomposition of the apocrine secretion, performed by the bacterial flora normally present on the skin.
The bad smell is given by the presence of substances such as amines, ammonia and mercaptans (deriving from protein decomposition), but also by the presence of short chain fatty acids (in particular caprylic and butyric), which come from the hydrolysis of triglycerides.
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