Question

Which hormone contains iodine
A. Testosterone
B. Thyroxine
C. Adrenalin
D. Insulin

Answer 1

Chemical messengers which are secreted directly into the blood are known as hormones. Hormones have specific functions such as excitatory or inhibitory action.

Complete answer:
Let us analyse the options to find the correct answer.
A) Testis, a reproductive part is present in the scrotal sac of male individuals. Testis act as primary sex organ as well as endocrine gland. Testis are made up of seminiferous tubules, stomal or interstitial tissue. The interstitial or leydig cells produces testosterone hormone. These hormones play a major stimulatory role in the process of spermatogenesis. It acts on central neural system and affects male sexual behavior i.e known as libido. Failure of testosterone in male causes eunuchoidism. Therefore, this is the incorrect option.
B) The thyroid gland is located on either side of the trachea. It becomes smaller with age. Thyroid glands are the largest endocrine glands in the body. Thyroid gland secretes Tetra-iodothyronine and Triiodothyronine. These hormones contain Iodine. Iodine is essential for the normal rate of hormone synthesis in the thyroid. Deficiency of iodine in diet results in enlargement of thyroid gland i.e. Goitre. Therefore, this is the correct option.
C) There are two yellowish glands located on the kidney which are adrenal glands. It has two types of tissues-Adrenal medulla (central) and adrenal cortex (outside). Adrenal medulla secretes-Adrenaline and noradrenaline hormones. These two hormones are derived from amino acid tyrosine and rapidly secreted in response to stress and during emergencies. Hence are known as emergency hormones. Adrenaline regulates heartbeat, blood pressure, sympathetic nervous system, contraction of involuntary muscles of lungs, eyes, gut etc. production of blood, flow of saliva and sweat under emotional state. Therefore, this is the incorrect option.
D) It is released from the $\beta$-cells of pancreas. It is a peptide hormone, plays an important role in the regulation of glucose homeostasis. Insulin acts on hepatocytes and adipocytes and enhances cellular glucose uptake and utilization. Therefore, this is the incorrect option.

Thus, the correct answer is option (B) thyroxine.

Note: Hypo secretion of thyroid gland causes cretinism in children myxedema in adults. Hypersecretion causes Graves’ disease and exophthalmic goiter. $C{a^{2 + }}$ level in the body is controlled by both thyroid gland and parathyroid gland.