Hypothalamic Pituitary Thyroid Axis (regulation, TRH, TSH, thyroid hormones T3 and T4)

hello in this video we're going to talk about the hypothalamic pituitary thyroid axis the hypothalamic axis plays the major role in regulating thyroid hormone homeostasis in the body the thyroid hormones are very important in fetal development and metabolism important structures are the hypothalamus the pituitary gland specifically the anterior pituitary gland and the thyroid gland the thyroid gland is located at the base of the neck and wraps around the trachea just below the cricoid cartilage here is a zoomed-in structure of the hypothalamus and the pituitary gland the hypothalamic pituitary thyroid axis is under the control of neurons located in the median region of the pvn that synthesize and release thyrotropin-releasing hormone trh into the pituitary portal circulation grh which is a tripeptide stimulates the release of TSH thyroid stimulating hormone from the anterior pituitary which in turn travels towards a thyroid gland to stimulate the synthesis and the release of thyroid hormones again thyrotropin-releasing hormone trh stimulates the synthesis and secretion of thyroid stimulating hormone TSH which acts at the thyroid to stimulate all steps of thyroid hormone bio synthesis and secretion by binding unto thyroid stimulating hormone receptors the thyroid hormones are tired of thyroid and t3 and thyroxine t for these thyroid hormones control the secretion of trh and TSH by negative feedback to maintain the physiological levels of the main hormones of the hypothalamic pituitary thyroid axis reduction of circulating thyroid hormones t3 and t4 levels due to primary third failure results in increased trh and TSH levels whereas if there is high thyroid hormone so high t3 and t4 the opposite occurs you have low trh and low TSH the functional units of the thyroid glands are the follicles made up of follicular cells the center of the follicle is the colloid the thyroid gland has a rich blood supply and here the capillaries which will bring TSH thyroid stimulating hormones to these cells next to the follicles are the power of follicular cells also known as C cells which produce calcitonin another hormone which will not talk about but has an important role in calcium homeostasis zooming closer now at the interaction between the capillary and the follicle the capillaries of course brings thyroid stimulating hormone to the area the inner part of the follicle is a colloid Ascenta on the follicular cells you have thyroid stimulating hormone receptors when thyroid stimulating hormone reaches the thyroid follicular cells it binds to thyroid stimulating hormone receptors causing a number of things firstly it will stimulate thyroid globulin production thyroid globulin will enter the colloid thyroid globulin contains tyrosine groups which are important in making the thyroid hormones TSH also stimulates the expression of channels such as sodium iodide channels allowing circulating iodide to enter the follicular cells from here iodide enters the colloid via another channel and becomes oxidized to iodine iodine and thyroglobulin is what makes our thyroid hormones t3 and t4 t3 and t4 will enter circulation the thyroid hormones travel in circulation bound to proteins the main protein being thyroxine binding protein and here it will target the different cells around our body to elicit an effect so increasing metabolism and that concludes a brief overview of the hypothalamic pituitary thyroid axis as well as some physiology of the thyroid planned you

Channel: Armando Hasudungan

Views: 128,979

Rating: 4.908124 out of 5

Keywords: thyroid hormone synthesis, thyroid hormone physiology, pituitary gland physiology, hypothalamus pituitary axis, hypothalamus pituitary thyroid axis physiology, thyroid disease, thyroid symptoms, thyroid problems in men and women, thyroid gland anatomy, thyroid gland physiology, thyroid gland anatomy and physiology, thyroid gland function, thyroid hormones physiology, thyroid hormone regulation, thyroid hormone function, endocrine system thyroid gland

Id: KzM8BiSnKQM

Length: 4min 55sec (295 seconds)

Published: Mon Jun 24 2019