Which of the following do you think would have the most severe effect on digestion: the surgical removal of the stomach, the gallbladder, or the pancreas? Why?

The surgical removal of the pancreas would likely have the most severe effect on digestion compared to the removal of the stomach or gallbladder. This is because the pancreas plays a crucial role in digestion as well as in regulating blood sugar levels. The pancreas secretes digestive enzymes into the small intestine (via the pancreatic duct) that help to break down proteins, fats, and carbohydrates. Moreover, it produces hormones like insulin and glucagon, which regulate blood sugar levels.

Without the pancreas, a person would lose the source of key digestive enzymes which are essential for breaking down nutrients in the foods we consume. Additionally, they would develop diabetes due to the absence of insulin production, necessitating life-long administration of digestive enzymes and insulin.

While removal of the stomach, known as a gastrectomy, or of the gallbladder, known as a cholecystectomy, undoubtedly impacts digestion, there are more adaptive mechanisms or treatments to manage their absence.

In the case of stomach removal, the digestive system can adapt over time by expanding the small intestine to increase nutrient absorption. The stomach is primarily responsible for churning food and initiating the breakdown of proteins, but actual nutrient absorption occurs in the small intestine.

For the gallbladder, after its removal, bile produced by the liver can still flow directly into the small intestine, although the bile is not as well regulated. The gallbladder's main role is to store and concentrate bile, which helps in the digestion and absorption of fats, but its removal does not completely stop bile from reaching the intestines.