Which of the following organs is responsible for the production of insulin?

Step 1: Analyze the question The question asks which organ produces insulin, a hormone that controls blood sugar.

Step 2: Explain the concept Insulin is made by the beta cells of the islets of Langerhans in the pancreas. The pancreas is both:

• An exocrine gland, secreting digestive enzymes (amylase, lipase, trypsin) through the pancreatic duct.
• An endocrine gland, secreting hormones directly into the blood (insulin and glucagon).

Step 3: Work through the options

• A. Spleen: It filters blood, destroys old red blood cells and helps with immunity. It does not make insulin.
• B. Adrenal gland: It produces adrenaline, noradrenaline and cortisol, which handle the "fight or flight" response and stress.
• C. Thyroid gland: It produces thyroxine, which controls metabolic rate.
• D. Pancreas: It produces insulin, which lowers blood glucose by helping cells absorb glucose and by promoting the conversion of excess glucose to glycogen in the liver.

Step 4: Answer The correct option is D. Pancreas.

Related point: If the pancreas doesn't produce enough insulin, the result is diabetes mellitus.

Exam tip: Remember "Insulin = Islets of Langerhans = pancreas". Insulin lowers blood sugar, while glucagon raises it. WASSCE often asks about this pair, so learn them together.