KCET 2017 Biology Solved Paper

→ Parafollicular cells or C cells lie between follicles. They produce the protein hormone thyrocalcitonin (TCT), which helps regulate calcium and phosphate homeostasis. It lowers blood levels=s of Ca2+ and HPO42− by inhibiting bone resorption and by accelerating uptake of calcium and phosphates into bone extracellular matrix.
→ Chief (principal) cells, produce a peptide hormone called parathyroid hormone (PTH). The blood calcium level directly controls the secretion of both calcitonin and parathyroid hormone via negative feedback loops