Gastrointestinal System

Amylase digests carbohydrate; lipase digests lipids; nuclease digests nucleic acids.

The “lip-” part of lipase indicates that it digests lipids, while the “-ase” part is indicative of an enzyme. Lingual lipase is produce by the salivary glands, not the pancreas.

Deamination, and making the non-essential amino acids, occurs in the liver. Pepsinogen is produced in the stomach lining, insulin in the pancreas and choice D in the intestine.

Bile contains “surfactants” which congregate on the interface between lipid and water and so prevent small droplets of fat from aggregating into larger ones (=emulsification).

The liver produces many proteins (spleen recycles RBC; liver converts lactic acid back into pyruvic acid; kidney produces renin).

Bile is a liver product that is stored in the gall bladder.

The churning of chyme is part of mechanical digestion. While some simple molecules (water, aspirin, glucose) can be absorbed from the stomach, most absorption occurs after digestion in the small intestine.

The parietal cells of gastric glands produce hydrochloric acid. (Zymogenic cells are the same as chief cells; they produce pepsinogen.)

In fact the reverse is true. Glucose is consumed during the production of ATP.

Digested fats absorbed from the gut are transported in the lymph. They re-enter the bloodstream via the thoracic duct and then travel to the heart.