Animal Nutrition Quiz 4

Option A is incorrect. Excess amino acids are deaminated in the liver. The amino groups are removed and converted into urea.

Option B is correct. Detoxification of alcohol occurs in the liver. An enzyme, alcohol dehydrogenase, in the liver cells break downs the alcohol to acetaldehyde. Acetaldehyde can be broken down further to compounds that can be used in respiration to provide energy for cell activities.

 Option C is incorrect. Excretion is carried out by the kidney.

Option D is incorrect. Liver converts excess glucose to glycogen/fat for storage.

The products of digestion absorbed by the villi in the ileum are carried directly to the liver by the hepatic portal vein. Excess glucose is stored as insoluble glycogen in the liver and muscle cells.

The end products of hydrolysis of fats are fatty acids and glycerol. They are absorbed by the lacteal in the villus. They recombine to form oil droplets inside the lacteal and are transported in lymph to the lymphatic system, and finally into the bloodstream.

Region Z is the duodenum. Acidic contents of the stomach are neutralized by the alkaline environment. Fat digestion begins and protein digestion continues in the duodenum. Digestive enzymes are supplied by the small intestine and pancreas. The liver produces bile, which emulsifies fats.

Enzyme pepsin requires an optimum pH of 2 to digest protein. The dilute hydrochloric acid in the gastric juice of the stomach provides the acidic medium for pepsin to hydrolyze protein.

Bile is stored in gall bladder (2) and released into duodenum (4) for fat digestion.

The ileum is the much-coiled part of small intestine.

Bile helps to emulsify fats to increase the surface area for enzyme lipase to digest fat. Bile is produced by the liver and lipase is secreted by lipase by the pancreas.

The lacteal absorbs end-products of fat digestion: fatty acids and glycerol, and transport them to the lymphatic vessels that eventually empty into the blood circulation in the neck.

Oxygen is required for active transport to occur, when the rate of absorption in the presence of oxygen is similar to the rate of absorption (such as fatty acids and glycerol), it implies the substance is absorbed mainly by diffusion. On the other hand, if the rate of absorption is higher in the presence of oxygen than in the absence of oxygen (such as amino acids and glucose), it implies the substance is absorbed by both diffusion and active transport.

Blood flows away from the liver into the hepatic vein (1) which travels back to the heart via the vena cava. From the aorta, blood flows away from the heart and travels to the liver via the hepatic artery (2). Digested food, such as sucrose and amino acids, is transported into the liver from the small intestine via the hepatic portal vein (3).