Question

Exophthalmic goitre (graves disease) is caused due to
(a) Hypofunction of thyroid
(b) Hyperfunction of thyroid
(c) Hypofunction of parathyroid
(d) Hyperfunction of parathyroid

Answer 1

Hint: Increased iodine in the body or rapid division of cells due to some abnormal conditions like cancer leads to an increase in activity of the follicular cells in the second-largest endocrine gland.

Complete answer:
Thyroid glands secrete hormones such as thyroxine and triiodothyronine. For the normal synthesis of thyroid hormones, iodine is necessary. when the iodine levels in the body increase or decrease it leads to fluctuations in secretions of thyroid hormones that lead to abnormalities. When the iodine levels increase or the cells in thyroid glands grow rapidly in cancer conditions, it leads to hyperthyroidism which further leads to a condition called an exophthalmic goitre.

Additional information:
- The largest endocrine glands present in the body are thyroid glands.
- They are mesodermal in origin
- Thyroid glands consist of two lobes which are connected by the isthmus
- It consists of stromal tissue and follicle, follicular cells are present in the follicle that encloses the cavity
- Follicles in the thyroid gland produces two hormones namely tetraiodothyronine and triiodothyronine
- The hormones released by the thyroid glands help in stimulation in the production of RBC by a process called erythropoiesis.
- Metabolism of proteins, carbohydrates and fats is controlled by thyroid hormones.
- Water and electrolytes balance is also influenced by thyroid hormones
- Exophthalmic goitre is characterized by protruded eyeballs.
So the correct answer is 'hyperfunction of thyroid' .

Note:
- Hypo secretion of thyroid gland hormones leads to the condition called simple goitre that is caused due to inadequate supply of iodine.
- Hypothyroidism in pregnancy leads to the conditions in the foetus called cretinism.