Which of the following substances is secreted by the pancreas?

• A. Thyroxine
• B. Melatonin
• C. Insulin
• D. Adrenaline

Answer: (C)

Verified step by step guidance

1. Step 1: Begin by identifying the role of the pancreas in the human body. The pancreas is a gland located behind the stomach that plays a crucial role in both the digestive and endocrine systems.
2. Step 2: Understand the endocrine function of the pancreas. It secretes hormones directly into the bloodstream to regulate blood sugar levels. The primary hormones secreted by the pancreas are insulin and glucagon.
3. Step 3: Review the functions of the substances listed in the question: Thyroxine is secreted by the thyroid gland and regulates metabolism; Melatonin is secreted by the pineal gland and regulates sleep-wake cycles; Adrenaline is secreted by the adrenal glands and is involved in the fight-or-flight response.
4. Step 4: Focus on insulin, which is secreted by the beta cells of the pancreas. Insulin helps lower blood sugar levels by facilitating the uptake of glucose into cells and promoting its storage as glycogen in the liver.
5. Step 5: Conclude that insulin is the correct answer because it is the hormone secreted by the pancreas, unlike the other substances listed, which are secreted by different glands.