Final answer:
Calcitriol is necessary for absorbing dietary calcium and phosphate from the digestive tract, which is vital for bone health and various physiological processes.
Step-by-step explanation:
Calcitriol is required for absorbing dietary calcium and phosphate. This active form of vitamin D is produced in the kidney when hydroxylation adds an –OH group to calcidiol, resulting in calcitriol (1,25-dihydroxycholecalciferol). It plays a critical role in maintaining normal serum concentrations of calcium and phosphate, which are essential for bone health, muscle contraction, hormone secretion, and neurotransmitter release. Inadequate levels of calcium can lead to disorders like osteoporosis, osteomalacia in adults, and rickets in children, as well as problems with cell proliferation, neuromuscular function, blood clotting, and the inflammatory response.