Human Nutrition 1 – The Parathyroid Glands

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Parathyroid Glands

There are four structures primed at the lowermost exterior of the thyroid gland that comprise of the parathyroid. Parathyroid glands are responsible for the synthesis and secretion of a polypeptide called the parathyroid hormone which increases the concentration of Calcium (CA2) in the blood stream. Parathyroid hormone’s chemical composition is made up of eighty four amino acids. The parathyroid hormone or PTH can hugely increase the volume of CA2 in the blood in a handful of ways.

1. The Parathyroid Hormone will release the CA2 reserves from the bone reservoir (99.1 percent of our CA2 reserve can be found in the skeletal system.)
2. The PTH will synthesize CA2 to be reabsorbed from the kidney fluid that is found in its tubules.
3. The PTH can precipitate absorption of CA2 from the intestinal tract, through the mediation of calcitriol, which is the active state of Vitamin D.

The Parathyroid Glands regulate the amount of phospates in the body’s hemoglobin. By secreting the parathyroid hormone, it will lower the reabsorption rate of phospates in the kidney’s proximal tubules, therefore dropping the phosphate concentration in the blood.  

The Calcium Receptor

The parathyroid glands are composed of multi-organelle cells that contain G-protein receptors (This affects human nutrition through the increase or decrease of calcium in the blood). These receptors are responsible for binding calcium. The G-protein-coupled receptors are the same kind found in calcitonin producing cells of the thyroid gland and the kidneys. The purpose of the protein receptors is to depress the secretion of parathyroid hormone and lower the concentration of calcium in the blood. There are mutational disorders that can cause problems in Calcium absorption that are associated with calcium receptors.

1. Functional loss mutations occur when the mutant receptor is set to “off all the time”. This happens to candidates with mutations of high level calcium concentration in the bloodstream and low calciumin the urea. This is a predisposing factor for hyperthyroidism.
2. Functional gain mutations happen when the mutant receptor is set to “on all the time”. Candidates with this form of mutation will have a low level of calcium in their blood stream and a concentration of calcium in their urine. This is a predisposing factor for hypoparathyroidism.

Autoimmune diseases can also replicate one of the two genetic disorders wherein antibodies cling to the calcium receptors. Upon inhibition of the calcium receptor, this leads to hyperparathyroidism, and activation of receptors such as symptoms associated with Graves’ disease cause hypoparathyroidism.