Thyroid Gland and Hormones Quiz

What hormones are produced by the thyroid gland?

Answer explanation

The thyroid gland produces hormones such as thyroxine (T4) and triiodothyronine (T3), which regulate metabolism, growth, and development. These hormones are crucial for maintaining the body's energy levels.

What is the minimum iodine requirement per day?

• 50 micrograms/day

• 75 micrograms/day

• 100 micrograms/day

Answer explanation

The minimum iodine requirement per day for adults is 75 micrograms. This amount is essential for proper thyroid function and overall health, making 75 micrograms/day the correct choice.

What is the primary function of thyroid hormones?

• Regulate metabolism

• Regulate blood pressure

• Regulate heart rate

Answer explanation

The primary function of thyroid hormones is to regulate metabolism, which includes the body's energy production and usage. This is crucial for maintaining overall metabolic health.

What is the difference in secretion between T4 and T3?

• T4 is secreted more than T3

• T3 is secreted more than T4

• Both are secreted equally

Answer explanation

T4 (thyroxine) is secreted in greater amounts than T3 (triiodothyronine) by the thyroid gland. Approximately 80% of the thyroid hormone produced is T4, while T3 is produced in smaller quantities, making the correct choice T4 is secreted more than T3.

What stimulates the thyroid gland to produce more hormones?

• Thyroid Stimulating Hormone (TSH)

• Thyrotropin Releasing Hormone (TRH)

• Calcitonin

Answer explanation

The thyroid gland is primarily stimulated by Thyroid Stimulating Hormone (TSH), which is produced by the pituitary gland. TSH signals the thyroid to produce and release thyroid hormones, essential for metabolism.

What role does calcitonin play in the body?

Answer explanation

Calcitonin is a hormone produced by the thyroid gland that helps regulate calcium levels in the body by lowering blood calcium levels and inhibiting bone resorption, thus playing a crucial role in bone health.

What is the role of parafollicular cells in the thyroid?

• Produce calcitonin

• Regulate blood calcium levels

• Stimulate movement of calcium into bone

• All of the above

Answer explanation

Parafollicular cells in the thyroid produce calcitonin, which helps regulate blood calcium levels and stimulates the movement of calcium into bone. Therefore, the correct answer is 'All of the above'.

What is the difference in secretion between T3 and T4?

• T3 is secreted more than T4

• T4 is secreted more than T3

• Both are secreted equally

• T3 has greater biological activity

Answer explanation

T4 is secreted more than T3 by the thyroid gland. While T3 is more biologically active, the quantity of T4 produced is greater, making it the predominant thyroid hormone in circulation.

What is the first step in the synthesis of thyroid hormones?

• Iodide transport

• Iodination of thyroglobulin

• Coupling

• Proteolysis of thyroglobulin

Answer explanation

The first step in the synthesis of thyroid hormones is iodide transport, where iodide is actively taken up by thyroid follicular cells from the bloodstream, setting the stage for subsequent hormone synthesis.

What causes goiter?

• Iodine deficiency

• Hyperthyroidism

• Hypothyroidism

• All of the above

Answer explanation

Goiter is primarily caused by iodine deficiency, which is essential for thyroid hormone production. While hyperthyroidism and hypothyroidism can also lead to goiter, iodine deficiency is the most common cause.