Bone's Role in Calcium Homeostasis (Nursing)

00:01 So now let's switch gears and talk about the bones role in maintaining homeostasis in the body.

00:08 Specifically, the bones store 99% of the body's calcium.

00:14 The parathyroid gland, which is located on the posterior portion of the thyroid, secretes a hormone, the parathyroid hormone.

00:24 And this allows osteoclast to be stimulated, which are going to reabsorb the calcium from the bones and release it into the blood.

00:35 Parathyroid hormone also stimulates the production of another chemical calcitriol by the kidneys, and this also causes the body to retain or hold on to any calcium instead of getting rid of it through waste.

00:54 So if we look at the feedback loop associated with bone's role in Calcium homeostasis, what happens is the stimulus would be a decrease in the amount of blood calcium.

01:09 As the blood calcium levels decrease or are lowered, the parathyroid glands receive this message.

01:17 They then send this message to the parathyroid where it secretes the parathyroid hormone and the parathyroid hormone is going to activate the parathyroid hormone gene.

01:29 This gene then activates both the kidneys with calcitriol and the osteoclast in the bone to both retain calcium in the blood as well as to release calcium from the bones so that we may increase the levels of blood calcium in the body.

01:47 We do this until we return to the homeostatic level of blood calcium that we need in order for our body to perform functions.

01:57 As you will find in later chapters, the level of calcium in the blood is extremely important for us to carry out a lot of our everyday activities.