Final answer:
Vitamin D aids in the absorption of calcium and phosphorus in the intestine, supports bone growth and remodeling, and in the kidneys, converts to its active form, calcitriol, which is crucial for maintaining calcium levels in the blood.
Step-by-step explanation:
Vitamin D plays a crucial role in calcium homeostasis and bone metabolism. In the intestine, vitamin D increases the absorption of calcium and phosphorus, enhancing the body's ability to maintain strong and healthy bones. In the bones, it facilitates the depositing of calcium, aiding in bone growth and remodeling. Lastly, in the kidneys, vitamin D is hydroxylated to become calcitriol, the active form that promotes the reabsorption of calcium, helping to maintain proper calcium levels in the blood and prevent the loss of calcium in the urine.
Additionally, vitamin D plays a role in the immune system, with receptors on B and T cells, implicating its significance in preventing autoimmune diseases and immune deficiencies.