Healthy Stomach
Mucous Cell
Mucous cells are cells in the stomach that secrete mucous and sodium bicarb. The sodium bicarb neutralizes the harmful stomach acid and produces a protective lining around the inside of the stomach when combined with the mucous.
Parietal Cell
Parietal cells are cells in the stomach that secrete gastric acid and intrinsic factor (IF). Gastric acids aids in the breakdown of ingested food, sterilizes the stomach contents by killing bacteria, and aids in the absorption of iron. IF is important for vitamin B12 absorption.
Stomach
The stomach plays important functions in the early stages of digestion including storing, mixing, grinding, and sterilizing. The bottom portion of the stomach (antrum) performs peristalsis which aids in the mixing and grinding of food.
Diseased Stomach
Gastric Ulcer
Gastric ulcers are a breakdown of the lining of the stomach. A common cause is the chronic use of NSAIDs such as ibuprofen which inhibits mucous cells from producing the protective barrier of mucous and sodium bicarb.
Autoimmune Gastritis
Autoimmune gastritis is an autoimmune attack of parietal cells and intrinsic factor. This leads to parietal cell death and thus the loss of the main factors that they produce: gastric acid and intrinsic factor. This then leads to iron deficiency (loss of gastric acid) and vitamin B12 deficiency (loss of intrinsic factor) which leads to pernicious anemia: the inability to make new red blood cells.
GERD
GERD (gastroesophageal reflux disease) is the reflux or backup of gastric acid out of the stomach and up into the esophagus. This can cause pain and inflammation of the esophagus which can transition into Barrett's esophagus.
Stomach Treatment
Gastric ulcer -> Mucous cell
While stopping NSAIDs aids in NSAID-induced ulcers, the use of the Histamine receptor (H2) antagonist famotidine can reduce gastric acid and aid in healing.
Autoimmune gastritis -> Parietal cell
As parietal cells are lost in this disease, it is important to replace the factors that are lost. This can be done with supplementing with vitamin B12 and iron.
GERD -> Stomach
GERD can be treated by decreasing the levels of gastric acid in the stomach that can reflux into the esophagus. The most effective drugs are proton pump inhibitors (PPIs), such as omeprazole, that inhibit the secretion of gastric acid by parietal cells.
