Protein digesting enzyme pepsin is secreted in the:

The correct answer is stomach.

Key Points

• Pepsin is a proteolytic enzyme that is secreted by the chief cells in the stomach lining.
• The secretion is initially in the form of an inactive precursor called pepsinogen.
• Pepsinogen is converted to active pepsin in the acidic environment of the stomach, primarily due to the action of hydrochloric acid (HCl).
• Pepsin plays a crucial role in the digestion of proteins, breaking them down into smaller peptides.
• The pH level in the stomach, which ranges from 1.5 to 3.5, is optimal for pepsin activity.

Additional Information

• Chief Cells:
  • These are cells in the stomach lining that secrete pepsinogen and gastric lipase.
  • Chief cells are also known as zymogenic cells.
• Hydrochloric Acid (HCl):
  • Produced by parietal cells in the stomach lining.
  • Creates an acidic environment, which is necessary for the conversion of pepsinogen to pepsin.
• Gastric Mucosa:
  • The mucous membrane layer of the stomach, which contains the glands and the gastric pits.
  • Responsible for the secretion of gastric juices, including pepsinogen and HCl.
• Protein Digestion:
  • Starts in the stomach with the action of pepsin.
  • Continues in the small intestine with the help of other proteolytic enzymes like trypsin and chymotrypsin.