Question

You are working with a patient who has the pancreatic duct that connects the pancreas to the small intestine completely blocked. Starting with the mouth, explain if and how each organ of the digestive system processes a meal that only contains proteins. Explain what effect the blocked pancreatic duct would have on digestion in the small intestine.

Answer 1

Answer

Mouth :

• Mouth is the site for mechanical digestion of the food. The food is broken down into small peices and mixed with saliva to form a semisolid mass called bolus.
• Chemical digestion of proteins do not occur in mouth.

The bolus is carried down to the stomach via esophagus. Cardiac sphincter regulates the flow of bolus into stomach.

Stomach :

• In stomach, cheif cells release an inactive enzyme called pepsinogen.
• This enzyme is activated into pepsin by HCl released from parietal cells.
• Pepsin acts on protein molecules beginning its chemical digestion.
• Pepsin hydrolyzes protein into peptones.

The semi-digested chyme enters duodenum via pyloric sphincter.

Small intestine :

• Most of the chemical digestion occurs in duodenum region of small intestine.
• Pancreas is an accessory digestive gland that releases pancreatcic juice contains digestive enzymes for protein digestion such as trypsinogen, chemotrypsinogen and procarboxypeptidase. Once activated these enzymes breaks up peptide bonds.
• Trypsin converts peptones into smaller peptides.
• Chemotrypsin and carboxypeptidase converts smaller polypeptides and dipeptides to amino acids.
• Amino acids are the final product of protein breakdwon that is readily absorbed in small intestine.

Due to blocked pancreatic duct, the enzymes responsible for protein digestion cannot enter the duodenum.

The proteins in the chyme remains undigested and cannot be absorbed by enterocytes.

Undigested proteins are carried away in large intestine and are lost in feces.

The cells in the body cannot receive adequate amount of proteins leading to protein deficiency.

This can lead to multiple symptoms such as hair loss, metabolic disorders, muscle weakness, increased appetite.