Histology Guide

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Chapter 12 - Exocrine Glands

Exocrine glands secrete their products onto the surface of an epithelium.

Exocrine glands can be classified in various ways:

Unicellular exocrine glands release their products from epithelial cells specialized for secretion directly onto the surface of an epithelium (e.g., goblet cells in the intestinal and respiratory epithelium).

Multicellular exocorine glands are clusters of secretory cells that release their products through a duct onto the surface of an epithelium.

Examples of multicellular exocrine glands include the salivary glands, sweat glands, sebaceous glands, pancreas, and mammary glands. The salivary glands and exocrine pancreas are examined in this chapter.

Salivary Glands

The salivary glands secrete saliva that aids mastication, effective swallowing, and digestion. These glands contain two types of cells:

The major salivary glands differ in their secretions:

Salivary glands are compound tubuloalveolar in structure.

Exocrine Pancreas

The pancreas is the largest exocrine gland and is 95% exocrine tissue and 1-2% endocrine tissue. The exocrine portion is a purely serous gland which produces digestive enzymes that are released into the duodenum. The duct cells also secrete bicarbonate to neutralize acid from the stomach.

The exocrine pancreas is compound tubuloacinar in structure. Centroacinar cells are epithelial cells from the beginning of ducts that protrude into the acinar lumen.


The blood supply to exocrine glands can be seen after perfusion with a colored dye.

Dye Injection