Paracrine signals affect target cells very near the

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Unformatted text preview: s for the hormone. (Paracrine signals affect target cells very near the signal source and don’t involve the blood. Autocrine: secreting cell is also a target cell.) 2.exocrine: involving large amounts of cell product secreted apically into epithelial tubes called “ducts”. cell stimulates itself! Paracrine - blood not involved - near in proximity Autocrine - if cell secreting hormone also has receptor for it! Unicellular glands: can be endocrine or exocrine Single endocrine cells secreting specific paracrine hormones are fairly numerous in the epithelium lining the digestive and respiratory systems (and will be discussed later.) Classic unicellular exocrine glands are the mucus-secreting goblet cells: some glands can be just 1 cell! ex: certain heart muscle cells. (goblet bc of SHAPE -- specialized for MUCUS SECRETION -- abundant in pseudostrat. epithelia that line the trachea -- also simple columnar of GUT -- produce mucus that coats lining of gut) pseudostratified simple columnar Fig. 4-16 Fig. 4-18 How glands form during an organ’s development in the embryo: downgrowth of endothelium cells differentiate to form HOLLOW structure which is PARTIALLY DUCT and partially SECRATORY These two portions are continuous with lining & surr...
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