Osteoclasts, osteocytes, osteoblasts, bone lining cells. Osteoclasts break down old bone and damaged bone cells.They make space for new bone growth by releasing enzymes that break down the old bone. Osteoblasts build new bone cells. They function to build new bone cells, reshape bone cells as aging occurs and heal damaged or broken bones. Osteocytes primarily keep bones healthy by maintaining strength, but they also assist osteoblasts. They are the regulators of when osteoblasts are needed. Bone lining cells are old osteoblasts and they function to regulate calcium in and out of the bone.
The axial skeleton is known as the central skeleton, composed of the bones in the head, neck, back and chest. Whereas the appendicular skeleton is associated with the bones that attach to the axial skeleton. These consist of every other bone, including limbs and connecting bones.
The hormone responsible for regulating blood calcium levels is the parathyroid hormone (PTH). PTH increases calcium levels. The other hormone responsible for calcium levels is calcitonin which decreases the level of calcium. PTH increases calcium levels when they are too low by releasing excess stored calcium from the bones and kidneys. Calcitonin is used to lower calcium levels by blocking the breakdown of calcium and preventing the kidneys from absorbing it. Which in turn promotes the kidneys to lose calcium quicker.
References:
Osteoblasts & Osteoclasts: Function, Purpose & Anatomy (clevelandclinic.org)Links to an external site.
Bone Cells (washington.edu)Links to an external site.
Axial Skeleton: What Bones it Makes Up (clevelandclinic.org)Links to an external site.
Calcitonin: What It Is, Function & Side Effects (clevelandclinic.org)Links to an external site.
