Glands

Glands

1. Exocrine Glands

   • Unicellular
     • goblet cells
   • Multicellular
     • secretory portion
       • end-piece where epithelial cells secrete product
     • ductal portion
       • epithelium-lined, through which the product is delivered to the exterior of the gland
     • depending on structure ductal portion
       • simple exocrine gland
         • unbranched duct
         • straight
           • intestinal glands
         • coiled
           • sweat glands
         • tubular
           • gastric glands
       • compound exocrine gland
         • repeated branching pattern
         • tubular
         • compound tubuloacinar
           • salivary glands
         • compound acinar or alveolar
           • mammary glands
     • depending on their secretory products
       • Mucous glands
         • viscous secretion; lubricates or protects inner lining of organs
       • Serous glands
         • watery secretions, rich in enzymes
       • Mixed glands
         • both mucous and secretory
     • depending on the method they discharge their product
       • merocrine glands
         • pancreas
         • release by exocytosis without loss of cellular components
         • apocrine glands
           • mammary glands
           • discharge part of secretory cell as secretory product
       • holocrine glands
         • cells themselves become secretory product
         • gland cells collect lipids, die, and degenerate => sebum (secretory product)
         • sebaceous glands of skin
   • products to ducts

2. Endocrine Glands

   • products to circulatory system
   • highly vascularized; lined with capillary networks
   • individual cells
     • unicellular glands
     • enteroendocrine cells
       • digestive organs
   • endocrine tissue / portions
     • has both endocrine and exocrine glands
     • pancreatic islets in pancreas, male and female reproductive organs
   • endocrine organs
     • separate
     • pituitary, thyroid, parathyroid, adrenal glands