G cell
Encyclopedia
In anatomy
Anatomy
Anatomy is a branch of biology and medicine that is the consideration of the structure of living things. It is a general term that includes human anatomy, animal anatomy , and plant anatomy...

, the G cell is a type of cell in the stomach that secretes gastrin
Gastrin
In humans, gastrin is a peptide hormone that stimulates secretion of gastric acid by the parietal cells of the stomach and aids in gastric motility. It is released by G cells in the antrum of the stomach, duodenum, and the pancreas...

. It works in conjunction with gastric chief cell
Gastric chief cell
A gastric chief cell is a cell in the stomach that releases pepsinogen, gastric lipase and Chymosin...

s and parietal cells.

G cells are found deep within the gastric glands of the stomach
Stomach
The stomach is a muscular, hollow, dilated part of the alimentary canal which functions as an important organ of the digestive tract in some animals, including vertebrates, echinoderms, insects , and molluscs. It is involved in the second phase of digestion, following mastication .The stomach is...

 antrum
Antrum
In biology, antrum is a general term for a cavity or chamber which may have specific meaning in reference to certain organs or sites in the body.In vertebrates, it may mean for example:...

, and occasionally in the pancreas
Pancreas
The pancreas is a gland organ in the digestive and endocrine system of vertebrates. It is both an endocrine gland producing several important hormones, including insulin, glucagon, and somatostatin, as well as a digestive organ, secreting pancreatic juice containing digestive enzymes that assist...

.

The vagus nerve
Vagus nerve
The vagus nerve , also called pneumogastric nerve or cranial nerve X, is the tenth of twelve paired cranial nerves...

 innervates the G cells.

Gastrin-releasing peptide is released by the post-ganglionic fibers of the vagus nerve onto G cells during parasympathetic stimulation. The peptide hormone bombesin
Bombesin
Bombesin is a 14-amino acid peptide originally isolated from the skin of a frog. It has two known homologs in mammals called neuromedin B and gastrin-releasing peptide. It stimulates gastrin release from G cells. It activates three different G-protein-coupled receptors known as BBR1, -2, and -3. It...

 also stimulates gastrin release from G cells.

Gastrin-releasing peptide, as well as the presence of amino acids in the stomach, stimulates the release of gastrin from the G cells. Gastrin stimulates enterochromaffin-like cell
Enterochromaffin-like cell
Enterochromaffin-like cells or ECL cells are a type of neuroendocrine cells found in the gastric glands of the gastric mucosa beneath the epithelium, in particular in the vicinity of parietal cells. They are also considered a type of enteroendocrine cell....

s to release histamine
Histamine
Histamine is an organic nitrogen compound involved in local immune responses as well as regulating physiological function in the gut and acting as a neurotransmitter. Histamine triggers the inflammatory response. As part of an immune response to foreign pathogens, histamine is produced by...

.

Gastrin also targets parietal cell
Parietal cell
Parietal cells, or oxyntic cells, are the stomach epithelium cells that secrete gastric acid and intrinsic factor.Acetylcholine and gastrin . The histamine receptors act by increasing intracellular cAMP, whereas the muscarinic and gastrin receptors increase intracellular Ca2+ levels...

s by increasing the amount of histamine and the direct stimulation by gastrin, causing the parietal cells to increase HCl
Hydrochloric acid
Hydrochloric acid is a solution of hydrogen chloride in water, that is a highly corrosive, strong mineral acid with many industrial uses. It is found naturally in gastric acid....

 secretion in the stomach.

Histomorphology

G cell have a distinctive microscopic appearance that allows one to separate them from other cells in the gastric antrum; their nucleus is centrally located in the cell and the cytoplasm is clear. They are found in the mid portion of the gastric glands.

External links

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