Parathyroid glands

Question 1

The parathyroid gland appears in the adult as

Answer 1

a pair of inferior and a pair of superior “bumps” on the beside the (dorsal) thyroid (hence the name, “para”).

Question 2

The embryonic origin of this gland is from

Answer 2

the endoderm of the third and fourth pharyngeal pouches, and could also have ectoderm and neural crest contributions.

Question 3

The parathyroid glands are small structures located on

Answer 3

the posterior thyroid gland

Question 4

Parathyroid gland produces

Answer 4

parathyroid hormone (PTH), which regulates blood calcium levels.

Question 5

cause the production and secretion of PTH.

Answer 5

• Low blood calcium levels

Question 6

The parathyroid glands are found

Answer 6

external to thyroid capsule and posterior to the thyroid gland.

Question 7

Superior parathyroid glands usually lies

Answer 7

slightly more than 1cm superior to the point of entry of the inferior thyroid arteries into the thyroid gland

Question 8

Inferior parathyroid glands usually lie

Answer 8

slightly more than 1cm inferior to arterial entry point

Question 9

Most people have ____ parathyroid glands

Answer 9

4

Question 10

• Approx. 5% of people have more, whereas some only have 2 or even up to 6.

Question 11

Arterial supply

Answer 11

inferior and superior thyroid aa (and/or laryngeal/ esophageal and/or tracheal aa)

Question 12

Venous supply

Answer 12

parathyroid vv to thyroid plexus

Question 13

Nerve supply

Answer 13

• Nerve supply is abundant, derived from the thyroid branches of the cervical ganglia
  These nerves are vasomotor, these glands are hormonally regulated.

Question 14

lymphatic drainage:

Answer 14

• Lymphatic vessels from the parathyroid glands drain with those from the thyroid gland into the deep cervical group of lymph nodes as well as the paratracheal lymph nodes