Final answer:
Parathyroid hormone does not stimulate osteoblasts. Instead, PTH activates osteoclasts to resorb bone and release calcium into the blood. The role of osteoblasts is to form new bone and is regulated by different hormones.
Step-by-step explanation:
The student's question is about whether parathyroid hormone (PTH) stimulates the activity of bone-resorbing osteoblasts. This statement is not accurate. In fact, PTH stimulates osteoclasts, not osteoblasts. Osteoclasts are the cells responsible for bone resorption, which releases calcium into the bloodstream, while osteoblasts are involved in bone formation. The parathyroid glands secrete PTH in response to low blood calcium levels. PTH then activates osteoclasts, increasing the destruction of bone matrix and the release of inorganic calcium-phosphate salts. This process is pivotal in maintaining calcium homeostasis. Additionally, PTH enhances the reabsorption of calcium by the kidneys and indirectly increases the gastrointestinal absorption of dietary calcium by converting vitamin D into its active form, calcitriol. In contrast, osteoblast activity is promoted by other hormones such as growth hormone, thyroid hormone, and sex hormones.