Question

What are the structures and regions of the stomach?

Answer 1

Hint: Stomach is a J-shaped structure and lies between duodenum and esophagus. It lies just behind the diaphragm and towards the left of the abdominal cavity. It acts as a flexible organ in the body, which is able to hold up to three liters of food. It is a bag-like organ of the digestive system. It receives food from the esophageal region and passes it to the small intestine. A typical adult stomach is $15.2$cm wide and $30.5$cm long.

Complete answer

                                                              Fig: Parts of a Stomach

Stomach can be classified into four parts, namely:
1. Fundus or fundic region
2. Stomach body or intermediate region
3. Antrum
4. Pylorus or pyloric region

Fundus – it is an expanded area, which is curving up above the cardiac opening (cardiac opening is opening from the stomach into the esophageal region). It is a dome-shaped region, which exists in the top-left.

Stomach body – It is the central portion of the stomach, which is the largest structure. It is the expansive and main stomach chamber.

Antrum – it is a lower part of the stomach, which is a funnel-shaped region.

Pylorus – it is a narrowing region, where the stomach meets the small intestine. It connects duodenum and stomach.

Both cardiac and pyloric regions possess sphincter muscles, which keeps the neighboring region closed, with the exception during the food passage time.

Rugae are prominent folds present in the inner mucosal lining, which perform expansion.

Note:
Stomach performs some functions. It churns the food into a semi fluid acidic substance, called chyme. It kills any germs in food through the presence of hydrochloric acid. It aids in the partial digestion of foods and breakdown of proteins. It acts as a reservoir for ingested food. Further, it also behaves as a mixing and digestion chamber. It has two openings, one in the esophageal region and another in the duodenal region.