Thyroid+and+Parathyroid

The Thyroid and Parathyroid do NOT need to be located in the practical and so a picture is not available of them, but they are located in the ventral aspect of the neck near the trachea (also ventral to the trachea). They are more proximal to the head than the heart and are just distal to the larynx. The thyroid is butterlfy shaped and has the right and left lobes fused together laterally on either side of the pharynx. It regulates iodine uptake and metabolism (people with an iodine deficiency often develop goiters on their neck where their thyroid is located). The parathyroid is made up of 4 glands on the surface of the thyroid which regulate blood calcium and phosphorus levels.

Hormones:

Thyroid: Triiodothyromine (T3)- regulates metabolism Thyroxine (T4)- regulates metabolism Calcitonin- promotes calcium absorption into the bones from blood (lowers blood calcium levels)

Parathyroid: Parathyroid Hormone (PTH)- increases blood calcium levels by reducing bone calcium levels (opposite of Calcitonin)