Answer
The calcium blood level is expected to grow, as the increased secretion of PTH determines the breaking down of bone matrix in order to retrieve calcium ions from the body's own resources. As such, the PTH hormone triggers the action of osteoclasts as bone-destroying cells and regulates the blood calcium levels.
Work Step by Step
1. A negative feedback mechanisms sends signals to the body that something is lacking - in this case, calcium. Consequently, the body finds a way to supply itself with what it needs by asking if it already has any calcium stored.
2. Calcium is found as a salt in bones and teeth.
3. The secretion of PTH determined by the negative feedback mechanisms will start a process by which calcium is retrieved from our bones.
4. This process is called bone remodelling and is based on the action of osteoclasts, which are bone-destroying cells (note the "clasts" ending, which means "to break" in Greek) that break down bone matrix in order to release the needed calcium ions into the blood, where it is needed for muscle contraction, neural transmission, and blood clotting. The complementary danger is developing osteoporosis.
