How are exocrine glands classified?

Question

Grace Acocella · Accepted Answer

Exocrine glands are classified according to their mode of secretion and their structure.

Exocrine glands are glands that secrete their products through ducts that open onto body surfaces. They can be classified according to their mode of secretion and according to their structure.

#color(red)"Mode of secretion"#
Exocrine glands can secrete their products in three different ways (see image for explanation):

merocrine secretion
apocrine secretion
holocrine secretion

#color(red)"Structure"#
Exocrine glands can also be classified according to the structure of their ducts (see image):
- simple types : duct often doesn't branch
- compound types : duct branches multiple types
  
  The outsiders are unicellular exocrine glands. These are single cells that do not have ducts. They are still considered exocrine, because the cells excrete products directly on the surface.

Kai Andersen · Answer

undefined The structure and mode of secretion of exocrine glands are classified into two main categories: 1. Simple exocrine glands, which consist of a single unbranched duct; 2. Compound exocrine glands, which have a branched duct system; 3. Tubuloalveolar, which has both tubular and alveolar secretory portions; 4. Merocrine glands, which secrete their products by exocytosis; 5. Apocrine glands, which release cytoplasm in addition to secretory product; and 3. Holocrine glands, which release entire cells filled with secretory product.