Question

how digestion takes place in stomach​

Answer 1

The stomach receives food from the esophagus. As food reaches the end of the esophagus, it enters the stomach through a muscular valve called the lower esophageal sphincter. The stomach secretes acid and enzymes that digest food. The stomach muscles contract periodically, churning food to enhance digestion.

Answer 2

Answer:

When food reaches the stomach, it stays for approximately 4 to 5 hours. There are various gastric glands in the mucosa lining of the stomach. The mucus neck cells secrete mucus. The Peptic Cells secrete the proenzyme pepsinogen. The Parietal or Oxyntic Cells secrete HCl (Hydrochloric acid) and intrinsic factor that is essential for vitamin B12 absorption.

Food in the stomach gets mixed thoroughly with the gastric juices through the churning movements of the stomach muscle. This mass of food that is semi-digested, acidic and pulpy is called the chyme. It is mostly the proteins that get digested in the stomach. The mucus and the bicarbonates of the gastric juice help in protecting the mucosal epithelium from the highly acidic HCl. Mucus also helps in lubricating the food.

The different chemical reactions that take place in the stomach are summarised as follows.

Gastric juices and enzymes:

1.HCl provides the acidic pH.

2.Pepsinogen(proenzyme) is converted into Pepsin by HCl

3.Pepsin, in turn, converts protein into peptones & proteoses.

4.Prorenin (proenzyme) is converted into Renin by HCl.

5.Casein (milk protein) is converted into peptides by Renin.

6.After the action of the gastric juices and enzymes, food then enters the small intestine.