Which two hormones are primarily released by the thyroid gland?

• A. Parathyroid hormone and calcitonin
• B. Thyroxine (T4) and triiodothyronine (T3)
• C. Insulin and glucagon
• D. Cortisol and aldosterone

Answer: (B)

Verified step by step guidance

1. Understand the role of the thyroid gland: The thyroid gland is an endocrine gland located in the neck. It primarily regulates metabolism, growth, and development through the release of hormones.
2. Identify the hormones produced by the thyroid gland: The thyroid gland primarily produces two hormones, thyroxine (T4) and triiodothyronine (T3). These hormones are derived from iodine and are critical for metabolic regulation.
3. Differentiate thyroid hormones from other hormones: Parathyroid hormone (PTH) is secreted by the parathyroid glands, not the thyroid. Insulin and glucagon are secreted by the pancreas, and cortisol and aldosterone are secreted by the adrenal glands.
4. Understand the function of T4 and T3: Thyroxine (T4) is the inactive form of the hormone, which is converted into the active form, triiodothyronine (T3), in target tissues. These hormones influence the metabolic rate, protein synthesis, and energy production.
5. Conclude that the correct answer is thyroxine (T4) and triiodothyronine (T3), as they are the primary hormones released by the thyroid gland.