1. MLAB 2401: Clinical Chemistry Keri Brophy-Martinez
Parathyroid gland

2. Anatomy
The parathyroid glands are four or more small glands located on the posterior surface (back side) of the thyroid gland.

3. Function & Regulation
Maintain the body’s calcium level for proper functioning of nervous and muscular systems
In situations of low blood calcium, the parathyroid senses this and releases PTH hormone that work to increase calcium levels
High blood Ca+ level
Low blood Ca+ level
Breakdown of bone matrix decreases
Breakdown of bone matrix increases
Normal blood Ca+ Level

4. Parathyroid hormone (PTH)
Sole hormone secreted by parathyroid, from the chief cells
Also known as parathyrin

5. PTH Action Raise serum concentration of calcium How?
Promotes reabsorption of calcium from bone
Increases kidney tubule reabsorption of calcium by a process where phosphate and bicarbonate is excreted
Activates vitamin D, assists in absorption in the gut

6. Calcitonin Produced by the thyroid Action Increase bone formation
Inhibit bone breakdown
Lowers blood calcium levels
Antagonistic to PTH

7. Disorders Hyperparathyroidism Causes Benign adenoma
Hyperplasia of tissue in response to chronic calcium loss
Secretion of PTH from malignant non-endocrine tumor

8. Hyperparathyroidism Results Increased PTH
Increased urine and serum calcium
Decreased serum phosphorous
Increased urine phosphorous
Kidney problems (stones)
Bone problems (demineralization)

9. Hypoparathyroidism Causes Results Primary Secondary Decrease PTH
Idiopathic
Secondary
Thyroid/ parathyroid surgery
Autoimmune diseases
Results
Decrease PTH
Decreased serum calcium
Increased serum phosphorous

10. References
Bishop, M., Fody, E., & Schoeff, l. (2010). Clinical Chemistry: Techniques, principles, Correlations. Baltimore: Wolters Kluwer Lippincott Williams & Wilkins.
Sunheimer, R., & Graves, L. (2010). Clinical Laboratory Chemistry. Upper Saddle River: Pearson .