Thyroid Gland Function

hello this video is on the thyroid gland we can't really talk about the thyroid gland unless we first talked about the pituitary gland so let's start with that over here the pituitary gland is located in the brain it's often nicknamed the master gland and it makes a hormone called thyroid stimulating hormone that causes the thyroid gland to produce and release a toxin let's make an arrow and then a little bowtie structure it usually looks kinda like a dog bone or a bowtie that's the thyroid gland okay let's put some color on here so we'll put our arrow in blue and let's put the gland in pink there's the pituitary gland and it's this anterior section that makes thyroid stimulating hormone and label the thyroid gland the thyroid gland is located attached to the trachea so in your neck region and the pituitary gland is located in the brain so this hormone travels in the blood to the thyroid gland and let's put the names of hormones in green so the next hormone is thyroid stimulating hormone otherwise known as t-sh and what it is able to do then is that hormone binds to actually goes in to the thyroid gland and when it's there it stimulates the production of thyroxine so let's make another arrow this way and we get a product hormone product set this in blue and then remember we're writing hormones in green so the name of this hormone is that Roxon and it comes in two forms t3 and t4 and this is just my cartoon way of showing you that thyroxine t3 has three iodine's and t4 has four iodine's and that's the next thing i want to show you is that in order to make that Roxon you have to have enough iodine available and usually that iodine comes from the diet so let's write that in orange so iodine in the diet is incorporated into the thyroid gland the thyroid gland is actually kind of a greedy iodine eater if someone has tyroid cancer and they are trying to have some of the thyroid cells killed they actually could give them radioactive iodine and what we sucked up into the thyroid gland and it destroys thyroid tissue so it's one way to control fire and cancer okay so the iodine in the diet is incorporated into a bigger structure called thyroglobulin so I'm going to use green for this even though it's actually not an active hormone it is the precursor of thyroxine it's basically like t3 and t4 stuck together and then they have to get cleaved and when they get cleaved you get t3 and t4 so t3 has three iodine's on it and t4 has four iodine's on it then another hormone I want to put on here is testosterone because testosterone stimulates the process of thyroxine production to and because of this men will typically have a higher metabolism than women since remember the thyroid gland is also known as our metabolic gland okay and then let's talk about a goiter for a second what is a goiter well if there's not enough iodine in the diet which can happen in very rural places where they don't have the ability to ship in seafood or fish and because iodine is very naturally occurring in the ocean so if they don't have access to that then they might not get enough iodine in their diet and what will happen is they will just keep on trying to make thyroid globulin but until it can incorporate the iodine it's not able to cleave it into two effective products and so the thyroid gland will actually get bigger and bigger and bigger and bigger but it's not actually producing active hormones we'll talk more about that too in a minute with the feedback loop so normally what happens then and these are black arrow back to the pituitary gland the presence of these hormones in the blood actually feeds back to the pituitary gland which can then sense okay do we need more thyroxine or do we need less if it thinks that we need more then it will release more TSH if it thinks we need less then it will release less TSH is that sort of will help you understand why it is that if there is plenty of thyroxine in the blood then less TSH will be released but if there is not enough thyroxine in the blood then more TSH will be released and that's what we call a negative feedback loop and it should work great right unfortunately it seems like there's a lot of places where this feedback loop gets a little out of whack and sometimes that can be the source of thyroid problems let's write that on here that negative feedback loop does that make sense that when I say negative feedback it means that t3 and t4 the thyroxine hormone actually inhibit more of the TSH so what this means is that if someone is not making enough thyroxine then they should actually have elevated TSH so we can write that over here hypothyroidism are not having enough of thyroxine is actually diagnosed by elevated TSH and then can you figure out the next part of it how would we diagnose hyperthyroidism clinically it's the opposite right so it's gonna be diagnosed by low TSH so I'll walk you through how that would be so if someone is making too much thyroid s'en then what will happen is they will not make as much TSH because their body's trying to bring that back into balance so if they are hyper thyroid then they'll have low TSH and if they're high both I or they'll have elevated TSH it's certainly not a perfect system it's not a direct measurement of the thyroxine in the blood and that's one of the things that I believe makes diagnosing and then treating long term thyroid imbalances okay now let's talk about what the hormone actually does so we use another arrow and I'm going to give you I think four main functions of these metabolic hormones okay so number one you're going to see an increase in ATP production by virtually all cells in the body brain cells are going to make more ATP muscle cells are going to make more ATP more cellular activity in general will be happening everywhere so let's use a good example though particularly of like a muscle cell I'm going to use a green highlighter here who would have known you have green muscles a and so what we need in order to make ATP is increased oxygen consumption because that's necessary for aerobic cellular respiration and increased glucose consumption so see how you're using fuel and then we see an increase in cellular activity because of that okay so that's the first one I wanted to show you a sec yet function is really a direct effect of increasing ATP production and that is see if we can draw a little heart right here that part you're gonna see an increase in heart rate and an increase in blood pressure as a direct effect of thyroxine so that's job number two then job number three is in bone thyroxine will stimulate it to make more red blood cells in the bone marrow let's get a little more color on here so our heart of course pink and the bone marrow here okay and then the last oh and this should maybe make sense right because if you make more red blood cells you can carry more oxygen so that's why it would make sense because then your meanwhile you're using more oxygen and if you're increasing heart rate then you can get that blood to all of the cells that need it given the let's put a three on there then the fourth one well good luck here let's draw a little brain medulla cerebellum okay so in the brain because of the increased activity there can be a sense of energy like an energized brain and also like a clarity of thinking so we've got mood energy and clear thinking so you can see that it does so many great things for us right it helps us think better it helps us feel better it helps us have more energy and it helps all of our cells get more oxygen more glucose to them so that we can increase the activity and work of basically the productivity of all of our cells in our body so what I want to show you now though are what can happen when we have either too much or not enough I'm going to start with not enough and looks like we're getting kind of part at the bottom of the page so I'll just put this over here okay hypothyroidism there's different reasons why people can get hypothyroidism sometimes there's an imbalance after pregnancy or childbirth we don't always know why and sometimes there's an autoimmune disease that can cause it like Hashimoto's where our own ad antibodies are damaging the thyroid gland and then we're going to compare hypothyroidism with hyperthyroidism actually I'm a little disappointed in myself right here because let's put these right across from each other so like verses so that you'll see what I mean here when we do this table and I was trying to use my space do it down here okay all right so Graves disease is a common name for an autoimmune disease that over stimulates the thyroid gland and Hashimoto's is the name of an autoimmune disease that causes under activity of the thyroid gland notice they're both just named after the discoverers of the clinical symptoms okay so now let's think about what would happen to you if you didn't have enough thyroxine and these effects in the brain weren't working right let's use a purple pen for that we would see instead of clear thinking foggy thinking and instead of feeling good we might be depressed and have low energy and then let's contrast that if someone has too much then instead of theirs these are not necessarily gonna feel great what we tend to see clinically is maybe they are agitated and irritable kind of like they're wound up so tight they're not able to be easygoing about things okay so now what else might happen if we look at the heart effects let's use a pink pen for that so maybe it wouldn't surprise you that if someone's hypothyroid that their heart rate might be low and their blood pressure might be low like a lower resting heart rate and low blood pressure and believe it or not people you think you know we talked about how bad high blood pressure isn't sure it is but when people have low blood pressure they feel really sluggish they just don't feel good let's contrast that with hyperthyroidism this patient might have a rapid heart rate maybe even palpitations kind of an irregular rhythm they might have high blood pressure and one of the symptoms of high blood pressure in the face like behind the eyes is it actually can cause something call caused something called exophthalmos and this is when the eyes protrude because of a buildup of pressure behind them okay now let's look at what might happen if there are not making enough red blood cells so I'll just use my black pen for this when someone doesn't have enough red blood blood cells do you know what that is called anemia which literally means no blood but of course clinically it just means not having enough red blood cells the symptoms of anemia because blood is warm is that they're often cold also they're not making enough ATP but we'll get to that one in a second they are pale and they are tired because their cells can't get enough blood to be able to make the ATP they need to make and then sort of countering that we might see with too many red blood cells that the patient is actually hot we can sometimes call this polycythemia I don't know if that it really gets that word described when someone's dealing with hyperthyroidism but if they have too many see the poly too many blood cells then they might feel hot they might be flushed and I don't know about saying that then they're energetic but we could go up to the irritable maybe maybe restless I think that's generally probably more a brain effect though okay then a couple other reasons that they're feeling tired and having low energy is because their cells are not able to bake the ATP that they need so let's use a green pen for that because that's also because they're not making enough ATP so if we look at this then we might say that they would also be potentially overweight because they are not able to use the glucose in their body the fatty acids in their body to make ATP and they might be fatigued because let's say they want to get up and go running but their cells can't even make the ATP needed for all of that muscle contraction they actually are feeling tired so it can also be a vicious cycle they're feeling tired because they can't make enough ATP so they don't exercise so they are not able to use as much of their stored energies whereas someone that is hyperthyroid using the green pen again they would be probably be thinner or losing maybe losing weight and again we're back to that Restless you see that's kind of a theme with this okay so if someone has let's say these symptoms and they go to the doctor the doctor will check their TSH levels and which ones would confirm a hypothyroid diagnosis would be elevated thyroid stimulating hormone actually confirms that the patient is suffering from hypothyroidism and then I had wanted to bring up the one more thing on this page hyperthyroidism sometimes can be caused by cancer of the thyroid or other diseases too and one of the ways that they treat it is by trying to kill the thyroid cells and if we go back to how the Roxxon is made hopefully this makes sense to you that if you give the person a radioactive iodine that radioactive iodine is incorporated into the thyroid gland and it literally kills thyroid cells thanks for your attention

Channel: susannaheinze

Views: 50,902

Rating: 4.8272729 out of 5

Keywords: thyroxine, negative feedback, pituitary gland, thyroid hormones, ertythropoiesis, hypothyroidism, hyperthyroidism

Id: oxEnC-itIJ0

Length: 21min 38sec (1298 seconds)

Published: Thu Dec 17 2015