Problem 9 - Biology: The Dynamic Science

Question

Which of the following best describes regulation of digestion? a. GIP inhibits insulin release from the pancreas. b. Gastrin stimulates pancreatic secretion of \(\mathrm{HCl}\) and pepsinogen. c. Secretin stimulates gastric emptying into the duodenum. d. CCK stimulates gastric activity to activate the duodenum. e. Leptin binds different hypothalamic receptors to stimulate or inhibit appetite.

Step-by-Step Solution

Answer

The best description of digestive regulation among the given is option e: Leptin binds different hypothalamic receptors to stimulate or inhibit appetite.

Step 1: Understand each Option

For each option, determine if the described function aligns with the known specific function of each hormone. GIP enhances the release of insulin from the pancreas, rather than inhibits it (option a is incorrect). Gastrin stimulates gastric glands to secrete pepsinogen and hydrochloric acid that digest proteins, but it doesn't stimulate the pancreas (option b is incorrect). Secretin does stimulate the pancreas to release bicarbonate-rich fluids, but typically slows down the stomach's process of emptying contents into the duodenum to allow neutralization to occur before too much acidic content passes into the small intestine (option c is incorrect). CCK stimulates the gallbladder to release bile into the intestine and signals the stomach to slow down gastric emptying, it's not directly related to gastric activity or the duodenum's activation (option d is incorrect).

Step 2: Final Decision

By understanding each hormone's role in digestive regulation, we can conclude that leptin, a hormone primarily associated with adipose cells, helps regulate energy balance by inhibiting hunger, which in turn diminishes fat storage in adipocytes. Its function as it relates to appetite aligns with the statement in option e. Therefore, this statement is correct.