Eccrine secretion is a mode of exocrine secretion, such as that followed in the salivary glands. Eccrine secretion is released via exocytosis without any cell loss. Overproduction or underproduction of eccrine secretions refers to various primary diseases.
What is eccrine secretion?
The large sweat glands in the genital and axillary areas also perform eccrine secretion. Glands and gland-like cells release their secretions by either endocrine or exocrine secretion. The exocrine glands channel their secretions through excretory ducts into a body cavity. This process can be realized in three different modes. The three modes of exocrine secretion are holocrine, apocrine, and eccrine secretion. Eccrine secretion is also called merocrine secretion and is the most common secretion mode in the human body. It occurs, for example, in the salivary glands and in parts of the pancreas. In this mode, the secretion is delivered by a process called exocytosis. Only rarely are the terms eccrine and merocrine secretion distinguished today. If the two forms were distinguished, eccrine secretion would be described in the broadest sense as secretion via ducts, transporters, or pumps in the apical plasma membrane without secretory granules in the cytoplasm. In contrast, merocrine secretion would be the delivery of secretory granules without loss of cellular materials.
Function and task
In eccrine secretion, the so-called exocytosis plays a key role. During exocytosis, vesicles from the cytosol of a cell fuse with the cell membrane. In this way, substances stored in the vesicles are released. This process is usually hormonally controlled and thus stimulated by the binding of hormones to receptors on cell surfaces. In ectrine glands, the membrane of a secretory granule fuses with an apical plasma membrane. In this way, the secretory granules are opened toward the surface. Via endocytosis, the fused membrane is reabsorbed back into the cytoplasm and can be used for further granules. Endocytosis refers to the uptake of non-cellular substances into a cell, which usually occurs either by invagination or strangulation of cell membrane parts. The fact that no cell loss occurs in eccrine secretion clearly distinguishes the eccrine mode from the holocrine mode, in which the secreting cells themselves become the secretion and thus perish. As an example of eccrine secretion, the eccrine part of the sweat glands can be mentioned. Each sweat gland consists of numerous glandular cells. In the endoplasmic reticulum of these cells, the sweat secretion is collected before it migrates to the Golgi apparatus of the cells where it is prepared. Together with the secretory granules, the stored secretion reaches the surface of the cell. The secretory granules and the cell membrane then fuse, opening in the process. During this opening, the secretion is released into the excretory ducts of the respective gland and the person begins to sweat. In total, the human body has around two to four million eccrine sweat glands. The large sweat glands in the genital and armpit areas also secrete in this way. The eccrine secretion of these glands is not only involved in thermoregulation, but also establishes the acid mantle of the skin and also fulfills detoxifying functions. Even the secretion of saliva occurs in the eccrine mode and is controlled by the autonomic nervous system. Saliva protects the oral mucosa from drying out, serves to neutralize acids and is involved in endogenous processes of oral hygiene. In the pancreas, only part of the secretion is eccrine secretion. The pancreatic secretion mainly performs important functions in digestion. In the mammary gland, the eccrine secretion mode also provides for the release of proteins. Accordingly, eccrine secretion performs many functions in the human organism.
Diseases and ailments
The eccrine sweat glands in particular may be responsible for underproduction or overproduction of secretions. The inability to eccrine secretion is called anhidrosis in the case of the sweat glands and can cause circulatory problems, because the thermoregulation by sweat can no longer be realized. The cause of the phenomenon may be related to the glands themselves or to dysregulation by the nervous system.The opposite of a lack of sweat secretion is hyperhidrosis. In this very strong eccrine secretion, the glands release a lot of sweat. Hyperhidrosis is often perceived as a psychological burden by those affected and can be symptomatic of various primary diseases. Hyper secretion due to psychological problems may also occur in some circumstances. Sclerotherapy of the hyperactive eccrine glands can provide relief for this condition. Blockages of eccrine glands are just as common as hyperhidrosis. Such blockages can lead to a congestion of secretions, which in the long term may result in the formation of tumors or even abscesses. These tumors are usually benign and are also known as adenomas. Over- and under-secretion can affect not only the sweat glands but also all other eccrine glands. Especially in the case of the pancreas, a primary disease of the organ may be the cause of dysregulated secretions. In the salivary glands, decreased secretion usually manifests as dry mouth and dental disease. Sometimes, swallowing and speech difficulties also occur. Like all other eccrine glands, the salivary glands themselves are rarely the cause of secretion complaints. In most cases, misdirected eccrine secretion refers to an existing primary disease.
