Lab 6: Digestive System

Gastrin functions to increase the production of HCl in the stomach.

True

In the parietal cell, carbonic acid dissociates into a bicarbonate ion and a hydrogen ion.

True

Which of the following does NOT stimulate the secretion of HCl in the stomach?

Secretin

Which of the following might stimulate the cephalic phase of gastric secretion?

The thought of food

Which phase(s) of gastric secretion is (are) regulated by the medulla oblongata?

All three phases are regulated by the medulla oblongata.

A portal triad consists of which three elements?

Branches of a hepatic artery, hepatic vein, and bile duct

Gastric secretion is increased in all three phases (cephalic, gastric, intestinal).

False

When chyme enters the duodenum, gastric secretion increases

False

The liver lobule is the same as a hepatocyte.

False/A hepatocyte is a liver cell and a liver lobule is a functional unit composed of many individual cells.

The enzyme carbonic anhydrase catalyzes the formation of bicarbonate from carbon dioxide and hydrogen.

False/Carbonic anhydrase catalyzes the reversible reaction between carbon dioxide and water to form carbonic acid.

The carbonic acid ion is joined to a hydrogen ion by the enzyme carbonic anhydrase.

False/Carbonic anhydrase performs the reversible reaction between a bicarbonate ion and hydrogen ion to form carbonic acid.

Structurally, the human liver is divided into how many lobes?

Four

________ ions are actively transported into the gastric gland duct, in exchange for ________ ions which enter the parietal cells.

Hydrogen; potassium

Which of the following enzymes is produced by the stomach?

Pepsin

The ion exchange protein in the plasma membrane of parietal cells exchanges ________ ions going out for ________ ions coming in.

bicarbonate; chloride

In the parietal cells, the enzyme carbonic anhydrase causes a reaction between

carbon dioxide and water.

The hydrogen ions used to form hydrochloric acid in the stomach are derived from

carbonic acid

Secretin is released from the duodenum in response to

hydrochloric acid in chyme.

Hydrochloric acid is formed when

hydrogen ions and chloride ions join in the duct of the gastric gland.

Gastric secretion during the intestinal phase is inhibited by the

presence of lipids or low pH.