The Thyroid Gland's Relationship within the Endocrine System

How to Subscribe
MLS & MLT Comprehensive CE Package
Includes 176 CE courses, most popular
$109Add to cart
Pick Your Courses
Up to 8 CE hours
$55Add to cart
Individual course$25Add to cart
Need multiple seats for your university or lab? Get a quote
The page below is a sample from the LabCE course Laboratory Assessment of Thyroid Function. Access the complete course and earn ASCLS P.A.C.E.-approved continuing education credits by subscribing online.

Learn more about Laboratory Assessment of Thyroid Function (online CE course)
The Thyroid Gland's Relationship within the Endocrine System

The thyroid gland is designed to be in perfect harmony with the pituitary gland and the endocrine system. After a meal or in anticipation of energy needs, the hypothalamus receives the summons to initiate the production of thyroid hormones. The hypothalamus provides a signal through the production of thyrotropin-releasing hormone (TRH) to the pituitary to produce thyroid-stimulating hormone (TSH).
TSH provides a positive stimulus for the thyroid gland to produce and release T4 into circulation, where T3 is derived and imparts its action on the metabolic processes. Excess T4 and T3 in circulation provide negative feedback to the hypothalamus and pituitary to stop signaling the need for additional thyroid hormone production. This is a classic negative feedback loop, and when in synchrony, it results in a very narrow and tightly regulated concentration of available free T4 (FT4) and free T3 (FT3) in circulation.