PSIO 532 Study Guide - Final Guide: Pernicious Anemia, Intrinsic Factor, Somatostatin
Graduate Physiology – GI Tract
Endocrine and Exocrine Secretion of the Stomach
Exocrine Cells
(release products into ducts)
- Mucus neck cells Mucus and bicarbonate ion (HCO3-)
- Parietal cells (HCl)
- Chief cells Pepsinogen
Endocrine cells (secrete into bloodstream)
-G cells: Gastrin
-D cells: Somatostatin
-P/D1 cells: Ghrelin
There are many types of cells in the gland:
these cells are scattered
-Need to know the Parietal and Chief
cells Parietal cells secrete HCl &
Chief cell secrete pepsinogen (only
enzyme in the stomach); both parietal
and chief cells are EXOCRINE cells; this
means they release their products
into the ducts (we never want to
release digestive enzymes into the
blood hence they go through the
exocrine cells [ducts] leading to the
lumen of the GI tract)
-In the ENDOCRINE cells (secrete in the
blood): G cells: secrete gastrin (stimulates HCl production), D cells (delta): secrete
somatostatin
-Somatostatin is an growth hormone inhibiting hormone it acts directly on the parietal
cells to decrease HCl secretion; Somatostatin can also indirectly decrease stomach acid
production by preventing the release of other hormones,
including gastrin, secretin and histamine which effectively slows down the digestive
process.
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