Thyroid and parathyroid

Question 1

In which species are the left and right thyroids joined by a functional isthmus?

Answer 1

• Pigs
• Humans
• Cattle

Does this point to an embryological origin from a paired or a single structure?

Duct divides into two, so a single structure! All animals have band between two sides, just depends on how active the tissue is!

Question 2

Which hormones are produced by the thyroid gland as a whole?

Answer 2

T3 and T4, as well as C cells producing calcitriol.

Question 3

In mammals, how many pairs of parathyroid glands are there?

Answer 3

P3 and P4

Question 4

Which hormone is produced by the parathyroid glands?

Answer 4

Parathyroid hormone from the chief cells

Question 5

Why is there such a variation in the location of the parathyroid glands?

Answer 5

Because it is a freely movable organ and depends on the embryology.

Question 6

Which anatomical features are important to know about when performing thyroidectomy, with respect to structures:

Near to the thyroid?

Part of the anatomy of the thyroid?

Answer 6

Near to the thyroid? Parathyroid gland as want to leave behind.

Part of the anatomy of the thyroid? P4 is inside, P3 outside!