Histo: Thyroid, Parathyroid

Question 1

Embryologic origin of the parathyroids.

Answer 1

Upper 3rd pharyngeal pouch: lower parathyroids

Upper 4th pharyngeal pouch: upper parathyroids

Question 2

Where would parathyroid tumors spread?

Answer 2

Depends on location of the gland.

If the gland forms within the thyroid, then tumor spread will not progress much further outside the thyroid gland

If the glands are outside the buccopharyngeal fascia, they can spread up to the base of the skull or down to the diaphragm.

Question 3

What supplies autonomics to the parathyroids and what is the function?

Answer 3

Superior and middle cervical ganglia.

Function is to regulate blood supply to the organ

Question 4

Name the two cell types that make up the parathyroid glands.

Answer 4

1. Principle Cells (dark nuclei, little cytoplasm)

2. Oxyphil Cells (larger proportion of cytoplasm with an eosinophilic stain)

Question 5

Which parathyroid cell type secretes PTH?

Answer 5

Principle Cells

Question 6

Name the embryologic source of the thyroid.

Answer 6

Two sources, 1 for each cell type.
1. Follicular Cells: come from the foramen cecum, a region of tissue that divides the ant. 2/3 of the tongue from the posterior 1/3

2. Parafollicular Cells (C cells): come from the ultimopharyngeal body of the lower 4th pharyngeal pouch

Question 7

Which fascial layer contains the thyroid gland.

Answer 7

Pretracheal fascia

Question 8

Where does lymph from the thyroid drain?

Answer 8

Deep cervical nodes (jugulodigastric and juguloomohyoid)

Question 9

Name the 3 blood vessel nerve pairs affilitated with the thyroid in the neck.

Answer 9

1. Superior Laryngeal Artery and Internal laryngeal nerve
2. Superior Thyroid artery and external laryngeal nerve
3. Inferior Thyroid artery and recurrent laryngeal nerve