Question

DIGESTION AND ABSORPTION

(A) Discuss the pre-pancreatic enzymes of digestion and include one usual abnormal finding

(B) Discuss the pancreatic enzymes of digestion and include one usual abnormal finding

(C) Discuss the small intestine absorption of nutrients and include one usual abnormal finding

(D) Discuss absorption in the large intestine and vitamin K regulation; include one usual abnormal finding

Answer 1

A. Pre pancreatic enzyme digestion: In the stomach the pepsinogen enzyme becomes activated with the action of Hydrochloric acid to form Pepsin, the proteolytic enzyme and it acts on the proteins in the food and digests the proteins into proteoses and peptones.

HCl---------> Pepsinogen ------>Pepsin--------> Proteins--------> Proteoses & Peptones

Abnormalities:

Excessive secretion of Hydrochloric acid and Pepsin enzyme causes Acid Peptic disease. It causes Gatritis, Peptic ulcer, heart burn, etc.,

B. Pancreatic Enzyme Digestion:

In the small intestine, Pancreatic Juice and Bile juice are released through hepato pancreatic duct. The pancreatic juice contains Chymotrypsinogen, Trypsinogen, amylases and lipases. First the enzyme Trypsinogen is activated by enterokinase secreted in the intestinal mucosa and the Trypsin activates other enzymes in the small intestine. The bile released into the duodenum helps in the emulsification of fats.

Trypsin,chymotrypsin

Proteins, proteoses, Proteoses-----------------------------> Dipeptides

Carboxypeptidase

Amylase

Polysaccharides-----------------------> Disaccharides

Lipase

Nucleic acids-------------------> Nucleotides-----------> Nucleosides

The succus entericus of the intestinal juice acts on these end products to further digest into simple absorbable forms of aminoacids, glucose, fatty acids.

Abnormalities:

Deficiency in pancreatic enzymes due to Exocrine Pancreatic Insufficiency may lead to indigestion of food. The symptoms include stomach pain, weight loss, foul smelling stools, bloating, etc., This pancreatic disease may be due to Chronic Pancreatitis, Schwachman Diamond syndrome.