Which hormone is secreted by the small intestine in response to the presence of acidic chyme?

• A. Insulin
• B. Gastrin
• C. Secretin
• D. Glucagon

Answer: (C)

Verified step by step guidance

1. Understand the role of the small intestine in digestion. The small intestine is responsible for absorbing nutrients and secreting hormones that aid in digestion.
2. Identify the stimulus for hormone secretion in the small intestine. Acidic chyme entering the small intestine from the stomach triggers the secretion of certain hormones.
3. Recognize the function of secretin. Secretin is a hormone that is secreted by the S cells in the duodenum of the small intestine in response to acidic chyme.
4. Learn how secretin works. Secretin stimulates the pancreas to release bicarbonate, which neutralizes the acidity of the chyme, protecting the intestinal lining and aiding in digestion.
5. Differentiate secretin from other hormones. Insulin and glucagon are primarily involved in blood sugar regulation, while gastrin is secreted by the stomach to stimulate gastric acid production. Secretin is specifically secreted by the small intestine in response to acidic chyme.