State where, in the digestive system, amylase, protease and lipase are secreted and where they act

SouravNovember 14, 2024

Answer

Amylase, proteases, and lipase are critical digestive enzymes that facilitate the breakdown of carbohydrates, proteins, and fats, respectively. Here’s a summary of where each enzyme is secreted and where they act within the digestive system:

Amylase

• Where Secreted:
  • Salivary Amylase: Secreted by the salivary glands in the mouth.
  • Pancreatic Amylase: Secreted by the pancreas into the small intestine (specifically the duodenum).
• Where It Acts:
  • In the Mouth: Salivary amylase begins the digestion of starch into simpler sugars during chewing.
  • In the Small Intestine: Pancreatic amylase continues this process, breaking down remaining starch into maltose and other simple sugars for absorption.

Proteases

• Where Secreted:
  • Pepsin: Secreted by the chief cells in the stomach as pepsinogen, which is activated by stomach acid.
  • Pancreatic Proteases: Secreted by the pancreas into the small intestine (duodenum) in inactive forms (e.g., trypsinogen, chymotrypsinogen) and activated there.
• Where It Acts:
  • In the Stomach: Pepsin begins protein digestion by breaking down proteins into smaller peptides.
  • In the Small Intestine: Pancreatic proteases further digest these peptides into amino acids for absorption.

Lipase

• Where Secreted:
  • Lingual Lipase: Secreted in saliva from glands in the mouth.
  • Gastric Lipase: Secreted in gastric juice from cells in the stomach.
  • Pancreatic Lipase: Secreted by the pancreas into the small intestine.
• Where It Acts:
  • In the Mouth and Stomach: Lingual and gastric lipases initiate fat digestion but are less effective due to limited fat emulsification.
  • In the Small Intestine: Pancreatic lipase acts on dietary fats (triglycerides), breaking them down into fatty acids and glycerol, aided by bile salts that emulsify fats for better enzyme access.