| Gastric glands | |
|---|---|
 Gastric glands shown atc and their ducts atd | |
| Details | |
| Identifiers | |
| Latin | glandulae gastricae |
| Anatomical terminology | |
Gastric glands areglands in the lining of thestomach that play an essential role in theprocess of digestion. Their secretions make up thedigestive gastric juice. The gastric glands open intogastric pits in themucosa. The gastric mucosa is covered insurface mucous cells that produce themucus necessary to protect the stomach'sepithelial lining fromgastric acid secreted byparietal cells in the glands, and frompepsin, a secreteddigestive enzyme. Surface mucous cells follow the indentations and partly line the gastric pits. Other mucus secreting cells are found in the necks of the glands. These aremucous neck cells that produce a different kind of mucus.
There are two types of gastric gland, theexocrine fundic or oxyntic gland, and theendocrine pyloric gland. The major type of gastric gland is the fundic gland that is present in the fundus and the body of the stomach making up about 80 per cent of the stomach area. These glands are often referred to simply as thegastric glands. The fundic gland contains theparietal cells that producehydrochloric acid andintrinsic factor, andchief cells that producepepsinogen andgastric lipase.
The pyloric gland is found in thepyloric region, the remaining 20 per cent of the stomach. The pyloric glands are mainly in thepyloric antrum. The pyloric gland secretesgastrin from itsG cells. Pyloric glands are similar in structure to the fundic glands but have hardly any parietal cells.
The gastric glands are glands in the lining of the stomach that play an essential role in the process ofdigestion. All of the glands have mucus-secretingfoveolar cells (also known as surface mucous cells) that line the stomach and partly line thegastric pits, and mucus-secretingmucous neck cells in the necks of the gastric glands.[1]Mucus lines the entire stomach asgastric mucosa protecting the stomach lining from the effects ofgastric acid produced by the parietal cells and released from the fundic glands.
Gastric glands are mostlyexocrine glands[2] and are all located beneath the gastric pits within the gastric mucosa.[3] The gastric mucosa is pitted with innumerable gastric pits which each house 3-5 gastric glands.[4] The cells of the exocrine glands (fundic glands) are mucous neck cells,chief cells, andparietal cells.[4] Mucous neck cells produce mucus, parietal cells secretehydrochloric acid andintrinsic factor, chief cells secretepepsinogen andgastric lipase.[4]
The other type of gastric gland is thepyloric gland which is anendocrine gland that secretes the hormonegastrin produced by itsG cells.
The secretions of the different exocrine gastric gland cells produce a watery, acidic fluid into the stomach lumen called gastric juice.[5][6] Gastric juice contains water,hydrochloric acid,intrinsic factor,pepsin, and salts. Adults produce around two to three litres of gastric juice per day.[5] The composition of the fluid varies according to the time of eating, and the rates of activity of the various cells. The cells are more active after eating. The composition of the gastric juice electrolytes is related to its rate of secretion: when secretion increases, the concentration of sodium decreases, and the concentration of hydrogen increases. There is always a higher level of potassium ions in the fluid than in the plasma.[5]
The glands are named for the region of the stomach that they occupy.
Thecardiac glands are found in thecardia of the stomach which is the part nearest to the heart, enclosing the opening where theesophagus joins to the stomach. Cardiac glands primarily secrete mucus.[7] They are fewer in number than the other gastric glands and are more shallowly positioned in the mucosa. There are two kinds - eithersimple tubular with short ducts orcompound racemose resembling theduodenalBrunner's glands.[citation needed]
Thefundic glands (oroxyntic glands), are found in thefundus andbody of the stomach. They are simple almost straight tubes, two or more of which open into a single duct.Oxyntic means acid-secreting and they secretehydrochloric acid (HCl) andintrinsic factor.[7]
Thepyloric glands are located in theantrum of thepylorus. They secretegastrin produced by theirG cells.[8]
There are millions ofgastric pits (also known asfoveolae) in the gastric mucosa and their necessary narrowness determines the tubular form of the gastric gland. More than one tube allows for the accommodation of more than one cell type. The form of each gastric gland is similar; they are all described as having a neck region that is closest to the pit entrance, and basal regions on the lower parts of the tubes.[9] The epithelium from the gastric mucosa travels into the pit and at the neck the epithelial cells change to short columnar granular cells. These cells almost fill the tube and the remaining lumen is continued as a very fine channel.
Cells found in the gastric glands include:
Fundic gland polyposis is a medical syndrome where thefundus and the body of thestomach develop manyfundic glandpolyps.
Pernicious anemia is caused when damaged parietal cells fail to produce the intrinsic factor necessary for the absorption of vitamin B12. This is the most common cause ofvitamin B12 deficiency.
List of distinct cell types in the adult human body
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This article incorporates text in thepublic domain from the 20th edition ofGray's Anatomy(1918)
