Final answer:
PTH is produced by the chief cells of the parathyroid glands and regulates blood calcium levels by influencing calcium reabsorption in the kidneys and bone dynamics.
Step-by-step explanation:
The parathyroid glands are responsible for the production of parathyroid hormone (PTH), which plays a crucial role in regulating blood calcium concentrations. PTH is produced by the chief cells located within these glands. When blood calcium levels fall below normal, PTH is secreted to increase the calcium levels by enhancing calcium reabsorption in the kidneys, stimulating osteoclast activity (which releases calcium from bones), and promoting the synthesis of calcitriol, which aids in dietary calcium absorption from the digestive system.
These functions of PTH maintain homeostatic calcium levels in the body.