Exocrine Glands


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•  Exocrine glands secrete to the surface of the body or the lumen of the gut

Exocrine glands produce and secrete substances via a duct onto an epithelial surface – either:

  • The surface of the body (e.g. sweat glands, sebaceous glands)
  • The lumen of the digestive tract / gut (e.g. digestive glands)

Examples of digestive glands include:

  • Salivary glands – secrete saliva which contains amylase (breaks down starch)
  • Gastric glands – secretes gastric juices which includes hydrochloric acid and proteases (breaks down protein)
  • Pancreatic glands – secretes pancreatic juices which include lipase, protease and amylase
  • Intestinal glands – secretes intestinal juices via crypts of Lieberkuhn in the intestinal wall

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•  Identification of exocrine gland cells that secrete digestive juices from electron micrographs

Exocrine glands are composed of a cluster of secretory cells which collectively form an acinus (plural = acini)

  • The acini are surrounded by a basement membrane and are held together by tight junctions between secretory cells
  • The secretory cells possess a highly developed ER and golgi network for material secretion and are rich in mitochondria

Exocrine products are released (via secretory vesicles) into a duct, which connects to an epithelial surface

  • These ducts may arise from a convergence of smaller ductules (each connected to an acinus) in order to enhance secretion

Structure of a Typical Exocrine Gland

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  Click on the image to contrast gland features – acinus (red) and duct (yellow)

Electron Micrograph of an Exocrine Gland


  Click on the image to show false colour representation