Anatomy- The PARATHYROID GLAND

Question 1

How many PARATHYROID GLANDS are there?

Answer 1

Usually 4
2 Superior
2 Inferior

Question 2

Where are the PARATHYROID GLANDS normally Located?

Answer 2

• SUPERIOR THYROID GLAND: The Posterior BORDER of the Thyroid Lobe above the level at which Inferior Thyroid artery crosses the Recurrent Laryngeal Nerve

-INFERIOR THYROID GLAND: Below the Inferior Thyroid Artery

Question 3

Describe the EMBRYOLOGY of the Parathyroid Glands?

Answer 3

• SUPERIOR PARTHYROID GLANDS: 4th Pharyngeal Pouch
• INFERIOR PARTHYROID GLANDS: 3rd Pharyngeal Pouch

Question 4

What is the ARTERIAL SUPPLY of the PARATHYROID GLANDS?

Answer 4

• Main Blood Supply is from the INFERIOR THYROID ARTERY

-Also Collateral Blood Supply from the SUPERIOR THYROID ARTERY and THYROID IMA ARTERY

Question 5

Where does the INFERIOR THYROID ARTERY come from?

Answer 5

SUBCLAVIAN ARTERY

Question 6

What is the VENOUS DRAINAGE of the THYROID?

Answer 6

Superior, Middle and Inferior Thyroid Veins

Question 7

What is the FUNCTION of the PARATHYROID HORMONE?

Answer 7

1) KIDNEY- Increases Renal Reabsorption of CALCIUM. INHIBITS the Reabsorption of PHOSPHATE

2) BONE- Stimulates OSTEOCLASTIC REABSORPTION of BONE

3) BOWEL- Increase ABSORPTION of Calcium from the small Intestine

Question 8

HISTOLOGICALLY what are the 2 MAIN CELLS that make up the PARATHYROID GLAND?

Answer 8

1) CHIEF CELLS/ PRINCIPAL CELLS

2) OXYPHIL CELLS

Question 9

What is the Role of the CHIEF CELLS?

Answer 9

• Synthesis and Secretion of PTH

Question 10

PARATHYROID GLAND

Answer 10