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Diffuse neuroendocrine system (APUD system)
Medical expert of the article
Last reviewed: 07.07.2025
The human body contains numerous hormone-producing cells originating from neural crest neuroblasts, ecto- and endoderm. These cells produce neuroamines and oligopeptides that have hormonal and biologically active effects.
Endocrine cells are distributed in the form of cell groups or individual endocrinocytes; they are united in the APUD system (Amine Precursors Uptake and Decarboxylation). The APUD system complements and connects (unites) the nervous and endocrine systems, carries out sensitive control of homeostasis. The APUD system includes parafollicular cells of the thyroid gland, cells of the adrenal medulla, neurosecretory cells of the hypothalamus, pinealocytes of the pineal gland, main parathyroid cells of the parathyroid glands, endocrinocytes of the adenohypophysis, placenta, pancreas, respiratory tree, gastrointestinal tract.
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