C cells, also known as parafollicular cells, are specialized cells found in the thyroid gland. They play a crucial role in regulating calcium levels in the body by producing the hormone calcitonin. This hormone helps lower blood calcium levels when they are too high, working in opposition to the hormone parathyroid hormone produced by the parathyroid glands. These cells are located between the thyroid follicles, which are responsible for producing thyroid hormones like thyroxine and triiodothyronine. C cells are important for maintaining calcium homeostasis, ensuring that the body functions properly and preventing conditions related to calcium imbalance, such as osteoporosis.