63.Exophthalmic goitre is due to A. Hyposecretion of thyroxine B. Hypersecretion of thyroxine C. Hypersecretion of thyrocalcitonin D. Hyposecretion of thyrocalcitonin
Option B Exophthalmic goitre is also known as Grave's disease. It occurs due to hypersecretion of thyroxine hormone from thyroid gland and is the most common cause of thyrotoxicosis in adults. In this disorder, high levels of thyroxine are secreted under the influence of thyroid stimulating hormone (TSH) from the anterior pituitary. The eyeballs get protruded due to deposition of excess fat behind the eyes and this is known as Exophthalmus.