Oesophagus and Structure of Stomach




The esophagus or the food pipe is a muscular tube and has the following features:
  • It starts from the pharynx to the stomach. The pharynx is present behind the trachea.
  • Food/bolus is pushed through the esophagus into the stomach by means of a series of contractions called peristalsis. These contractions occur in the muscles in its wall.
  • There is no digestion in this part.
  • It is also called as gullet.
  • The opening of the esophagus into the stomach is regulated by a muscular sphincter called gastro-esophageal sphincter. 



Structure of the stomach
It is a highly muscular, J-shaped organ.
It is located in the upper left portion of the abdominal cavity.
The stomach has three parts:
  • Cardiac portion: The esophagus opens here.
  • Fundic region
  • Pyloric portion: It opens in the first part of small intestine.
The opening of the stomach into the duodenum is guarded by the pyloric sphincter. 
The innermost layer lining the lumen is the mucosa. This layer forms irregular folds called rugae in the stomach.
Mucosa form gastric glands in the stomach.
Function of the stomach
The gastric glands present in its walls secrete gastric juice containing hydrochloric acid (HCl) and enzymes, like pepsinogen. 
HCl activates pepsinogen into pepsin and kills bacteria.
Proteins are broken into smaller fragments called peptones by the enzyme called pepsin.
It eventually leads to the formation of chyme, which is moved to the intestine through pylorus.