- Explain how HCl is produced by parietal cells.
HCl is produced by parietal cells in the stomach These cells have enzymes which secrete H+ ions into the stomach cavity. The H+ ions unite with Cl- ions to form HCl in the lumen of the stomach.
- Explain why drugs that suppress prostaglandin production may make a patient more susceptible to peptic ulcers
NSAIDs work by inhibiting two enzymes, substances that cause chemical changes in the body, called COX-1 and COX-2. Both enzymes produce prostaglandins—chemicals produced in the body's cells—that promote pain, inflammation, and fever.
However, unlike COX-2, COX-1 produces another type of prostaglandin that protects the stomach lining from stomach acid and helps control bleeding. By inhibiting COX-1, NSAIDs increase the risk of a peptic ulcer developing and bleeding.
- The recipes for oral rehydration therapy usually include sugar (sucrose) and table salt.The salt enhances intestinal absorption of glucose. Explain how.
It has to do with the transport carrier found in the intestinal cells that require both sodium and glucose. The transporter is initially oriented facing into the lumen - at this point it is capable of binding sodium, but not glucose. Sodium binds, inducing a conformational change that opens the glucose-binding pocket. Glucose binds and the transporter reorients in the membrane such that the pockets holding sodium and glucose are moved inside the cell. Sodium dissociates into the cytoplasm, causing glucose binding to destabilize
glucose dissociates into the cytoplasm and the unloaded transporter reorients back to its original, outward-facing position.
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