Which gland is responsible for producing the hormone insulin?

Step 1: Analyze the question The question asks which gland produces insulin, a hormone that controls blood sugar (glucose) levels.

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

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

How insulin works:

• After a meal, blood glucose rises.
• The beta cells release insulin.
• Insulin makes the liver and muscles convert excess glucose into glycogen (glycogenesis), and helps cells take up glucose.
• Blood glucose falls back to normal.

If the body does not produce enough insulin, or cannot respond to it, the result is diabetes mellitus.

Step 3: Check each option

• A. Thyroid gland: Produces thyroxine, which controls metabolic rate. Not insulin.
• B. Pituitary gland: The "master gland". Produces growth hormone, ADH, FSH, LH and others. Not insulin.
• C. Pancreas: Produces insulin and glucagon. This is correct.
• D. Adrenal gland: Produces adrenaline and cortisol. Not insulin.

Step 4: Answer The correct answer is C. Pancreas.

Exam tip: Remember "Insulin comes from Islets of Langerhans." Also remember that insulin and glucagon are opposites:

• Insulin lowers blood sugar.
• Glucagon raises blood sugar.

Both come from the pancreas, and JAMB likes to test this pair.