To answer the question of which type of cells secrete insulin, let's explore the functions of the different cells found in the pancreas. The pancreas has multiple types of cells that are part of the islets of Langerhans, each responsible for secreting different hormones:
- Alpha cells: These cells secrete glucagon, which raises blood glucose levels by promoting the release of glucose from the liver.
- Beta cells: These are the cells that secrete insulin. Insulin plays a crucial role in regulating blood glucose levels by facilitating the uptake of glucose into cells, thus lowering blood sugar levels.
- Delta cells: These cells secrete somatostatin, which inhibits the release of both glucagon and insulin, balancing their effects.
- Acinar cells: These are not part of the islets of Langerhans. Instead, they produce digestive enzymes that are secreted into the small intestine.
Given this information, the correct answer to the question "Insulin is secreted by _______" is clearly:
Beta cells
Options like alpha, delta, and acinar cells have different functions and secrete different substances as explained above. Therefore, the Beta cells are specifically responsible for insulin secretion in the pancreas.