This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Physiology
Osteoclast has specific receptor for : 
Select and explain. 
A. Parathyroid hormone., B. Calcitionin., C. Thyroxin., D. Vit D3.
B: Calcitionin.
Answer: B: Calcitionin. 
Explanation: B i.e. CalcitoninCalcitonin exes its Ca2+ lowering effect by inhibiting bone resorption. This action is direct and calcitonin inhibits the activity of osteoclase 2. It also increases Ca2+ excretion in urine.HormonesBone cells on which theirreceptors are presentCalcitoninOsteoclastQParathyroidOsteoblastQVitamin DOsteoblastQCalcitonin exes its Ca2+ lowering effect by inhibiting bone resorption. This action is direct and calcitonin inhibits the activity of osteoclase 2. It also increases Ca2+ excretion in urine.