Parathyroids

A. Location – 4 or 5 small round bodies on the posterior surface of the

lateral lobe of the thyroid gland

B. Function – secretes the Parathyroid hormone that controls Blood

Calcium homeostasis

1. increases Ca⁺² and Mg⁺² absorption from the Intestines,

Kidneys and Bones [raises blood calcium levels]

2. increases PO^-3 excretion [ lowers blood phoshate levels]

C. Disorders of parathyroid activity

1. Hypocalcemia – causes by hyposecretion of PTH

- results in Tetany [muscle spasms and convulsions]

2. Hypercalcemia – causes by hypersecretion of PTH

- results in a fibrous bone disease [osteitis fibrosa cystica

or also called Von Recklinghausen’s Disease of the bone]

Category: Physiology Notes