What Are Eccrine Glands?

Exocrine glands are different from endocrine glands. Exocrine glands are a type of glands with ducts (single-cell glands without ducts). Their secretions do not enter the blood and flow out of the ducts. If the liver produces bile, it flows through the common bile duct to the duodenum. Salivary glands, sweat glands, sebaceous glands, gastric glands, intestinal glands, liver, etc. are all exocrine glands.

Exocrine glands

Human body's largest

According to different perspectives, there are the following categories:

Glandular cells

Single-cell and multi-cell glands .

By glandular secretion

Total secretory glands : After one secretion, the glandular cells die and the cells themselves are contained in the secretion (such as the sebaceous glands).

Partial secretory glands : After the secretion is excreted, the cells can still survive and repeat the process of secretion production and excretion.

1, leakage of secretory glands: only excretion of secretions (such as salivary glands),

2, apocrine secretion glands: This corresponds to the intermediate type of total secretion glands and leaked secretion glands, that is, a part of the cytoplasm containing secretions is separated from the remaining part and discharged (such as the breast). However, it was found under the electron microscope that there were also a large amount of secretions and those separated from the cytoplasm in the leaking secretory glands, so it was difficult to distinguish them clearly.

Staining by cell secretions or pre-stage substances

Basophil gland: can be stained with basic dyes

Acidophil gland: stained with acid dyes

According to physiological functions, it can be divided into digestive glands, gonads, etc.

According to the type of secretion, it is called sweat gland, mucus gland, serous gland, etc.

By gland nature

Serous gonadal : It is composed of serous gonadal cells. The secretion of this glandular cell is a thin and clear liquid, rich in enzyme substances, and involved in digestive functions. Serous gonadal cells are mostly cone-shaped, and the cells are connected to each other to form spherical or oval-shaped vesicles. There is a narrow acinar cavity in the middle of the acinus. After the secretion is discharged from the cells, it first reaches the acinar cavity and then is discharged through the catheter. The rough endoplasmic reticulum in the glandular cytoplasm is rich and basophilic. The top of the cell contains many zymogen particles. The number of particles indicates that the glandular cells are in different secretion stages. Like parotid glands and pancreas

Mucus gonadal: It is composed of mucus gonadal cells. The secretion of this glandular cell is a viscous liquid whose chemical composition is mainly proteoglycan. The morphological characteristics of mucinous gonadal cells are very different from those of serous gonadal cells. The cytoplasm is filled with slime particles and is the precursor of secretions. On generally fixed stained sections, the slime particles are dissolved and often appear vacuole-like, so the cytoplasm is lightly colored. When the cytoplasm is filled with slime particles, the nucleus is squeezed to the side of the base of the cell, squeezed into a half-moon or flat shape, and darker in color. When the cell's secretions are expelled, the nucleus becomes round or oval. Esophageal gland

Mixed gonadal: Its secreted part has both mucinous gonadal cells and serous gonadal cells, so it is called mixed acinar. Its secretions are both mucus and serous. The structure of mixed acinar cells is generally a series of serous gland cells attached to the end of the mucinous acinus. Due to the different coloring of the two glandular cells, several darkly colored serous gland cells are arranged in a semi-moon shape, which is generally called a serous half-moon. Such as the submandibular and sublingual glands.