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Exocrine gland

  (Redirected from Exocrine system)

Exocrine glands are glands that produce and secrete substances onto an epithelial surface by way of a duct.[1] Examples of exocrine glands include sweat, salivary, mammary, ceruminous, lacrimal, sebaceous, and mucous. Exocrine glands are one of two types of glands in the human body, the other being endocrine glands, which secrete their products directly into the bloodstream. The liver and pancreas are both exocrine and endocrine glands; they are exocrine glands because they secrete products—bile and pancreatic juice—into the gastrointestinal tract through a series of ducts, and endocrine because they secrete other substances directly into the bloodstream.

Exocrine gland
Centroacinar cells.jpg
An acinus is a round cluster of exocrine cells connected to a duct.
Latin glandula exocrina
MeSH D005088
TH H2.
FMA 9596
Anatomical terminology



By structureEdit

Exocrine glands contain a glandular portion and a duct portion, the structures of which can be used to classify the gland.[1]

  • The duct portion may be branched (called compound) or unbranched (called simple).
  • The glandular portion may be tubular or acinar, or may be a mix of the two (called tubuloacinar). If the glandular portion branches, then the gland is called a branched gland.

By method of secretionEdit

Exocrine glands are named apocrine glands, holocrine glands, or merocrine glands based on how their products are secreted.[1]

  • Merocrine secretion – cells excrete their substances by exocytosis; for example, pancreatic acinar cells.
  • Apocrine secretion – a portion of the cell membrane that contains the excretion buds off.
  • Holocrine secretion – the entire cell disintegrates to excrete its substance; for example, sebaceous glands of the skin and nose.

By product secretedEdit

Additional imagesEdit

See alsoEdit


  1. ^ a b c Young B, Woodford P, O'Dowd G (2013). Wheater's Functional Histology: A Text and Colour Atlas (6th ed.). Elsevier. p. 95. ISBN 978-0702047473. 

External linksEdit