Thyroid Gland - Thyroid Hormones

hello you're watching armando hustling on biology and medicine videos please make sure to subscribe to join the forum in group play this videos visit Facebook alone and sugan like ask questions answer questions and please post some interesting things like your artworks and you can also change the settings to HD original for better graphics of this video now this video is going to talk about the thyroid gland the thyroid gland produces start hormones which regulates many metabolic processes in our body the thyroid gland is situated rama' throat if we zoom into this section we can find the hyoid bone and underneath it is the larynx and this butterfly looking structure is known as the thyroid gland now below the thyroid gland is the trachea connecting to the lungs the blood supply to the gland comes from the aorta which is right beneath it blood supply comes from the superior thyroid artery here and also the inferior thyroid artery the s the f-test moose here connects the two lobes of thyroid glands together and as mentioned the larynx is above the thyroid gland now if we zoom into the thyroid gland I'm saying thyroid gland so many times we can find few cells and the structure sort of looks like these now the red blood cells are found here which obvious because it supplies the thyroid we also have follicle cells follicular cells or principal cells here connected together too far forming the lumen coded colloid now each of these segments here are referred to as lobules which consists of 20 to 40 evenly dispersed follicle cells and it is here and is these follicle cells that produces the thyroid hormones so the follicular cells produces a thyroid hormones and there are two thyroid hormones triode Oh tyranny or t3 and thyroxine t4 so two types triode Authority t3 and thyroxine t4 the thyroid also produces calcitonin and other hormones but we are not looking at we're only looking at these two hormones and what t3 and t4 do essentially they is that they increase the metabolic rate amongst many other things so what helps regulate or stimulate the production of these two hormones well in the endocrine system the hypothalamus has a major role in stimulating glands the hypothalamus is situated around the brain if we zoom into this section here we can see the hypothalamus and two lobes underneath it known as the anterior and inferior pituitary glands and of course the thyroid gland is situated around the throat so butterfly looking thyroid gland so what happens is that the hypothalamus secretes thyroid releasing hormone which causes the anterior pituitary gland to secrete thyroid stimulating hormone TSH TSH thyroid stimulating hormone then causes a thyroid gland to produce the flower thyroid hormones t3 and t4 which then target specific types of cells now there's a negative feedback here too much production of these hormones t3 and t4 will inhibit the hypothalamus to secrete more thyroid releasing hormone to your age so how does the thyroid stimulating hormone stimulate thurid hormone production well if we zoom in here we see the membrane of the thyroid and a g-protein coupled receptor which gets activated once bound to thyroid stimulating hormone GDP is exchanged for GTP which increases they essentially cellular cyclic EMP levels which essentially increases the production of thyroid hormones now let's investigate how these hormones are actually synthesized just to recap the thyroid gland has lobules consisting of follicular cells which form circular looking lobules illumine and called the colloid now if we zoom into this particular section here we will begin to investigate how our own hormones are synthesized so here we have the follicular cells and the colloid inside it and around surrounding it are blood vessels there are many cations and anions in the bloodstream such as sodium iodide sodium iodide and potassium among many other things and inside the follicles the Salalah kill cells we have of course endoplasmic reticulum which synthesizes thyroid globulin and they start globulin get sent and packaged up by the Golgi apparatus into the colloid so tired goblin precursors packaged up and then put into the colloid and third globulin actually is a carbon chain you can say consisting of tyrosine many tyrosine molecules attached to it and these are what tyrosine looks like simplified diagram now let's go back to the blood vessels here the blood stream so to synthesize thyroid hormones we need iodide so what happens here is that there's a transporter known as the sodium and iodine symptom er which transports a sodium and also pumps up iodide at the same time so our that is now in the follicular cells now the sodium can go back out when potassium gets pumped in and it's exchanged for sodium so now that we have iodide in the follicular cells what happens is the iodide needs to be transported into the cord because synthesis the actual synthesis of thyroid hormones occurs in the colloid so how it does is there's a transporter called the pin drain which transports iodide which is a negatively charged chemical molecule in the same time it exchanges it for a core chlorine so now iodide is in the colloid there's a special enzyme in the colloid known as peroxidase which essentially oxidizes which actually oxidizes iodide to iodine now Dean well then bind to the tyrosine rings in the thyroid globulin and one iron the iodine can bind to a tyrosine ring or to iodine's can bind to a tyrosine ring when there is on one iodine bound to tyrosine ring it's MIT if there's two ayodhya Dean's binding to a tyrosine ring it's di T mit stands for mono I adult are C and D I T stands for die Rho tyrosine next MIT and di t or di t and di t can form extra bonds with each other so basically making a to tyrosine bind together um so if MIT and di T bind together we have three iodine molecules which is called triode Oh tyranny or t3 and if di t and di t binds binds together it will have four iodine molecules so thyroxine are t4 and as you might have already guessed there are these are our hormones but the process is not finished yet because there are still they're still hot they're still part of the thyroid globulin so MIT di t t3 and t4 can still be part of the thyroid globulin structure now next what happens is all these molecules will then get packaged up our via pinocytosis into the follicular cells in the follicular cells there are lysosomes and the lysosomes will bind together with the end ozone containing the thyroid globulin and will essentially release the fact that tyrosine molecules from the whole structure that are a goblin structure which causes because lysosomes are acidic and so it breaks things apart which then causes the t3 and t4 to separate and the MIT and di T if present in the endosome it can be di and di ordinated or deionized too to release the tyrosine and make and release the iodide molecules and the process can we start again so back here again we have the blood vessels and in these blood vessels there are special proteins are on the thyroid gland known as thyroid binding proteins because t3 and t4 the thyroid hormones are lipid hormones they cannot travel through the bloodstream by themselves and so they bind to these thyroid binding proteins which allows them to be transported around the body to various cells and tissues to initiate its metabolic effects and so the started binding protein travels through the bloodstream to various tissues it should be noted that t4 there's more t4 secreted by the follicular cyst follicular cells than the t3 however t3 is 10 times more active than t4 and so once they arrive at the target cells such as the heart or skeletal muscle t4 is converted to T 3 and T 3 just stays like t3 because t3 is more active and these lipid hormones t3 and t4 can pass through the outer membrane easily because they are lipid hormones their lipids and in the target cell it can be a hard and skeletal muscle once again there is a nucleus so what these lipid hormones actually do is that they enter the nucleus and in the nucleus there are two receptors that initiate transcription for thyroid hormone responses and these are the thyroid hormone receptor and the retinoid x receptor not racer receptor sorry and once t3 and t4 binds to the thyroid hormone receptor t3 binds to the top siren horn receptor it will initiate gene transcription for various for mrna specific mRNA that will promote the thyroid hormone response and so this mRNA will leave the nucleus and then synthesize new proteins which will promote again the function of thyroid hormones which is increasing the metabolic rate and by increasing the metabolic rate can have many effects depending on what target cell the thyroid hormone abided to for example it can promote growth in muscle and skeletal cells in brain cells promote CNS development it has various effect on metabolism increasing metabolism and also cardiovascular effects on my arm cardiac cells and it also had it also the proteins can also increase a limit a block rate in many other organ systems so for example in the cardiovascular cells these protein synthesis will increase my tablet grade by increasing cardiac output by increasing the heart rate and by increasing respiration in the metabolism it increases metabolism by increasing oxygen consumption in the body increasing our glucose absorption increasing gluconeogenesis increasing glycogenolysis which is the degradation of glycogen and increasing light lipolysis and also increasing protein synthesis and also the thyroid hormones will increase basal metabolic rate so I concludes this video for the thyroid hormone and everything in the thyroid hormones and thyroid gland hope you enjoyed it please like comment provide feedback and subscribe thank you very much right

Channel: Armando Hasudungan

Views: 965,575

Rating: 4.9469795 out of 5

Keywords: Thyroid, gland, hormone, t4, T3, production, thyroid, synthesis, colloid, follicle, principle, cells, follicular, TSH, TRH, triiodothyronine, (T3), and, thyroxine, (T4), secretion, endocrine, regulation, lecture, summary, overview, metabolism, Thyroid Hormone (Hormone)

Id: b7JFqGMi9pk

Length: 12min 46sec (766 seconds)

Published: Mon Oct 08 2012