Thyroid Gland Anatomy - (embryology, blood supply, venous drainage, innervation, histology)

hello in this video we're gonna talk about the anatomy of the thyroid gland the thyroid gland is a butterfly-shaped endocrine organ that sits and wraps around the trachea it produces three main hormones tried earth ironing and thyroxine which are important in metabolism and calcitonin in calcium homeostasis the thyroid has two main lobes the right and the left anterior Lee the thyroid glands are joined by the isthmus posteriorly the thyroid gland encircles the trachea but does not connect from this dorsal view we can see that there are four parathyroid glands which sit on the thyroid gland two on each side developmentally the third isthmus can give rise to a structure called the pyramidal lobe which extends upwards the pyramidal lobe is common in up to 55% of people and as a result of the persistent remnant of the thyroglossal duct the third gland is one of the first endocrine organs to become active in humans becoming active by the 24th week of gestation this early activity is important because much of fetal organ development depends on thyroid hormone so embryologically the thyroid gland begins its development at the base of the tongue a place called the foramen cecum from here it will descend down to the trachea it goes down forming the thyroglossal duct which should atrophy with time the thyroglossal duct cyst is a common congenital midline mass caused by the persisting thyroglossal duct tract the thyroglossal duct track does not atrophy but forms assists instead the cysts are usually painless unless it becomes infected clinically because the thorough gloss or duct arises from the base of the tongue the thyroglossal duct cyst will move with tongue protrusion the parameter lobe is again a result of the thyroglossal duct which may have not atrophied completely the thyroid gland is in the visceral compartment of the neck along with the trachea recurrent laryngeal nerve esophagus and the pharynx the compartment is enclosed in the pre-trip eel fashio which anchors the thyroid gland to the trachea so that the thyroid moves up with swallowing the thyroid gland stands at the vertebral level c5 and t1 here is a cross-section of the c64 table level while on this diagram the carotid sheath is adjacent to the preacher keel fashio and the cordage sheath is where the internal jugular vein and the common carotid artery runs and these are two important structures in the venous drainage as well as the arterial supply of the thyroid gland some histology now the functional units of the thyroid gland are the follicles the follicles are made up of a central cavity filled with sticky fluid called colloid surrounded by a wall of epithelial four little cells the colloid is the center of thyroid hormone production surrounding the follicles or capillaries now these follicular cells produce the classical thyroid hormones thyroxine and triiodothyronine the production of these hormones in the colloid rely on iodine another cells called the para follicular cells or the C cells are located between the follicles and produced a polypeptide hormone calcitonin which is important in calcium homeostasis focusing on the arterial supply of the thyroid gland relative to its weight the thyroid gland receives a greater flow of blood than most other tissues of the body this is probably because the thyroid hormones are extremely important and are transported via the blood the artery supplying the thyroid gland include the branch of the external carotid artery the superior thyroid artery a branch of the subclavian artery which is the thyroid cervical trunk and another branch from the thyroid cervical trunk the inferior thyroid artery and then we have the EEMA artery which is present in three percent of people and it's a branch of the brachial phallic artery running along the arteries are nerves which supply the laryngeal muscles the muscles for speech and voice these nerves are important for the anatomy of the thyroid because of its close proximity to the thyroid gland firstly the thyroid gland is innervated by the sympathetic nerves from the cervical ganglion but these nerves do not control secretion of the thyroid hormones the thyroid gland is also innervated by the parasympathetic nerve which we'll talk about now so the vagus nerve branches to form the superior laryngeal nerves which partly supply the thyroid gland but mainly the laryngeal muscles the right vagus nerve continues down and gives off another branch the right recurrent laryngeal nerve which may loop under the brachiocephalic artery and travel up supplying the thyroid gland but mainly supplying the laryngeal muscles after giving off the left superior laryngeal nerve the left vagus nerve continues down and gives off another branch the left recurrent laryngeal nerve which loops under the aortic arch and travels back up supplying the thyroid gland but mainly supplying the laryngeal muscles very important in speech and so performing a thyroidectomy removal of the third can potentially injure these laryngeal nerves and so cause a change in voice the venous drainage of the third is through the paired superior and middle thyroid veins into the internal jugular vein the internal jugular will drain into the brachiocephalic vein the inferior thyroid vein drains into the brachiocephalic vein which will then drain into the superior vena cava the gland is also endowed with a rich lymphatic system that may play an important role in the delivery of hormones to the general circulation the lymphatic drainage of the thyroid gland is extensive and flows in multi-directional pattern the thyroid lymphatic drainage drains into the pre trochee lymph nodes the para tricky lymph nodes the inferior deep cervical lymph nodes the superior deep cervical lymph nodes the pre laryngeal lymph nodes and even up to the submandibular and submental lymph nodes the nodes are important as cancer from the thyroid gland can move to these areas to these lymph nodes some clinical Anatomy let's talk about the tubercle of Zuko Kendal I don't know if I pronounced that right I apologize now the tubercle of the sucker candle is a pyramidal extension of the thyroid glands it's present at the most posterior side of each lobe now the recurrent laryngeal nerves which we talked about on the right on the left they actually transverse the posterior aspect of the tubercle and so this tubercle is a good area to help surgeons identify where the recurrent laryngeal nerve sits and to be careful thank you for watching I hope you enjoyed this video you

Channel: Armando Hasudungan

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Keywords: thyroid histology, thyroid gland anatomy, thyroid gland blood supply and venous drainage, thyroid gland surgery, thyroid gland venous drainage, recurrent laryngeal nerve anatomy, thyroid gland embryology, thyroid gland medicine, thyroid gland physiology, thyroid gland hormones, thyroid gland lecture, thyroid gland tutorial, thyroid gland animation

Id: CMwjlbt9ihM

Length: 8min 55sec (535 seconds)

Published: Wed Jul 24 2019