- Exam
- NEET
- Subject
- Zoology
- Chapter
- Chemical Coordination and Integration
NEET · Zoology · Chemical Coordination and Integration
What is exophthalmic goitre?
Options
- AA form of hypothyroidism
- BA form of hyperthyroidism
- CEnlargement of the thyroid gland
- DProtrusion of the eyeballs
Correct answer
B. A form of hyperthyroidism
Step-by-step solution
Exophthalmic goitre is a form of hyperthyroidism that is characterised by enlargement of the thyroid gland, protrusion of the eyeballs, increased basal metabolic rate, and weight loss, also called Graves’ disease. 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. Parathyroid hormone (PTH) increases the Ca²⁺ levels in the blood. PTH acts on bones and stimulates the process of bone resorption (dissolution/ demineralisation). PTH also stimulates reabsorption of Ca²⁺ by the renal tubules and increases Ca²⁺ absorption from the digested food. It is, thus, clear that PTH is a hypercalcemic hormone, i.e., it increases the blood Ca²⁺ levels. Along with TCT, it plays a significant role in calcium balance in the body.