Hypopa rathyroidism (Less secretion) :
Causes : Accidental
damage to the parathyroids or their blood supply during thyroidectomy
surgery. The deficiency of Ca2+ caused by this disorder causes neurons to depolarize without the usual stimulus.
So, nerve and muscle action potentials arise spontaneously. It leads to muscle twitch, spasms and convulsions. Now, the condition is known as hypocalcemic tetany.
Hyperparathyroidism (More secretion) :
Causes : A tumor in the parathyroids causes
hypersecretion of PTH hormone. This causes demineralization of bone. The bones are deformed and fractured easily. If untreated, this condition leads to osteitis fibrosa cystica. The areas of destroyed bone tissue are replaced by cavities which fill with fibrous tissue