Which of the following are NOT under the control of thyroid hormone?

A. Maintenance of water and electrolyte balance

B. Regulation of basal metabolic rate

C. Normal rhythm of sleep-wake cycle

D. Development of immune system

E. Support the process of RBCs formation

Choose the correct answer from the options given below:

C and D only

The correct answer is Option (2) - C and D only

The thyroid gland is composed of two lobes which are located on either side of the trachea . Both the lobes are interconnected with a thin flap of connective tissue called isthmus. The thyroid gland is composed of follicles and stromal tissues. Each thyroid follicle is composed of follicular cells, enclosing a cavity. These follicular cells synthesise two hormones, tetraiodothyronine or thyroxine (T₄) and triiodothyronine (T₃).Iodine is essential for the normal rate of hormone synthesis in the thyroid. Deficiency of iodine in our diet results in hypothyroidism and enlargement of the thyroid gland, commonly called goitre.

Thyroid hormones play an important role in the regulation of the basal metabolic rate.

These hormones also support the process of red blood cell formation.

Thyroid hormones control the metabolism of carbohydrates, proteins and fats.

Maintenance of water and electrolyte balance is also influenced by thyroid hormones. Thyroid gland also secretes a protein hormone called thyrocalcitonin (TCT) which regulates the blood calcium levels.

So statement A,B and E are under the control of thyroid hormone, and C and D are not .

Statement C: Normal rhythm of sleep-wake cycle. This statement is incorrect. Melatonin and the circadian rhythm play more significant roles in regulating the sleep-wake cycle.
Statement D: Development of the immune system. This statement is incorrect. Thyroid hormone does not directly affect the development of the immune system. The thymus gland is a lobular structure located between lungs behind sternum on the ventral side of aorta. The thymus plays a major role in the development of the immune system.