STOMACH
Description:
The stomach follows the esophagus in the alimentary canal. As food enters through the lower sphincter in the esophagus, the stomach secretes enzymes to break down the food further. Notably, the stomach will secrete pepsin, which is an activated version of the enzyme pepsinogen, breaking down proteins into amino acids. The activation of pepsinogen is accomplished in an acidic environment, which is achieved with the secretion of chyme, which also breaks down food. The lining of the stomach is filled with ridges called rugae, and the muscle layers underneath it will contract to mash the food to make it more digestible. After the nutrients are absorbed from the food, they will travel out of the stomach and travel out through the pyloric sphincter, which connects to the small intestine.
Diseases and Conditions
Gastric Ulcer
An ulcer is a sore in the stomach lining due to stomach acids. They are commonly caused by the bacteria Helicobacter pylori and lead to stomach discomfort and bleeding.
Dyspepsia
A general term to refer to indigestion, caused by unhealthy lifestyle choices such as eating too fast and alcohol consumption, but can also be caused by ulcers. It leads to bloating and burning sensations.
Stomach/Gastric Cancer:
Caused by carcinogens such as nitrates, most stomach cancers occur within the lining of the stomach and often spreads through the body.
Gastroparesis
Also referred to as delayed gastric emptying, it is a condition that is caused by nerve damage from diabetes which causes the stomach to not empty food as often as it should, leading to malnourishment and the growth of bacteria.
Zollinger-Ellison syndrome (ZES)
A tumor called gastrinoma in either the pancreas or duodenum of the small intestine causes a rapid rise in gastrin levels, leading to ulcers forming. It can be treated with proton pump inhibitors.