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Hormone feedback mechanism

Let's explore how the feedback mechanism regulates hormones. Created by Mahesh Shenoy.

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Video transcript

our bodies are very sensitive to hormones and so it's important to control the amount of hormones which is present in the blood so how does our body control that well that's basically we're gonna find out in this video so the ways of controlling the amount of hormones in our blood are regulating these hormones is done by a mechanism called the feedback mechanism so what exactly is this well to give you a broad overview it's a mechanism by which the the organs that secrete hormones they get a message of whether the hormones are doing their job or not and based on that message they will control they will decide whether to secrete more hormones or to secrete less now it'll make a lot of sense if I take a very specific example right so let's take the example of pancreas and insulin now we already talked about the role of pancreas in a previous video called the endocrine system but just to give you just to give you a recap whenever the blood sugar level rises beyond a point your pancreas tries to reduce it why why is it important to reduce it but because if you have too much blood sugar then that sugar can actually damage the blood vessels and as a result blood may not reach all the cell's oxygen may not reach all the cells the cells could die and that could be catastrophic so a very high blood sugar is very bad for us very dangerous for us and so for that what is the pantry I do well whenever pancreas detect a very high level of blood sugar you know what it does immediately it starts secreting a hormone called insulin insulin gets into the blood and it tells all the cells to start absorbing more blood sugar that's what insulin does it gives the message to the cells and as a result the cells start absorbing more blood sugar what does that do well because now more more sugar is being absorbed from the blood the blood sugar level starts dropping so the blood sugar starts dropping and now we are out of danger so this can happen immediately after eating something very sweet like cake or chocolate the moment that happens the blood sugar Rises your pancreas sacred insulin that ask the cells to absorb more blood sugar and that reduces the blood sugar now this is great but imagine if this kept on happening if this keeps on happening your blood sugar level will keep on dropping and after a point will become very low that's also bad we don't want too low blood sugar because if that also happens then your blood will not have any sugar and sugar is important because sugar gives you energy and so sugar is definitely needed and therefore if this continues that's also a problem so how do we make sure the blood sugar level doesn't drop too low so this is where the feedback mechanism comes into picture so the moment the blood sugar level drops beyond a particular point it goes low that message is fed back to the pancreas I mean think about it the blood goes to all the organs and so the pan this blood is going to the pancreas as well and so the pancreas detect that so once the blue the pancreas detect that the blood sugar has become low enough the pancreas says okay the blood sugar level is fine I don't need to produce more insulin so that stops the production of insulin or at least it reduces the production of insulin but let's say it stops over here just to keep it simple so that message stops and the cells stop absorbing more blood from the sugar and as a result the blood sugar level level will stay the same and everything stays fine and so you see this is how by using the feedback the pancreas can control the amount of insulin to be present in the blood this is the whole idea behind the feedback mechanism now of course if you study in more depth we will call this as a negative feedback because the message is making the organ reduce the amount of hormone secretion right there are other feedback mechanisms in which the message will make the organ increase the amount of hormone secretion but you know what for our case we don't have to worry too much about this positive and negative feedback don't worry about that just understand feedback mechanism in general so anyways for this let me take one more example let's now consider the example of the pituitary gland you may recall again from our previous video on endocrine systems that the pituitary gland is the master gland which controls the secretions of all the other endocrine glands right so let's can see how pituitary controls the thyroid glands so whenever you eat food let's say and your body needs energy that food needs to be metabolized so when that happens the pituitary senses that and it starts it starts triggering the thyroid gland so basically what happens over here is the pituitary gland sends a hormone to the tie-rod gland and you wonder them the name is not important just gonna write that down it's called the thyroid stimulating hormone okay so it sends a hormone to the thyroid gland and the name itself tells what does it Harmon do this hormone stimulates the thyroid basically it tells the thyroid hey tyroid start producing thyroxine okay so the thyroid gland starts producing start secreting thyroxine into the blood and as a result the blood thyroxine level starts arising and thyroxine is the one that conveys the message to the cells start metabolizing that food so it increases the metabolism of the food that's one of the things that oxen does and as a result your food starts getting metabolized and you start getting more energy great but again you don't want to metabolize too much you don't want to get too much energy in your body and so again this amount of thyroxine in the blood should also be controlled so how does that happen again by the feedback mechanism so once the blood thyroxine level increases beyond a point that message is fed back to the pituitary so the message goes back to the pituitary again because blood is given to all the organs even to the brain pituitary's in the brain and so the pituitary gets that message and then it realizes okay there is enough thyroxine in the blood i can reduce the amount of thyroxine and so the blood the pituitary is stopped so we just used yeah the pituitary stops sending the hormone to the thyroid gland and as a result the thyroid gland stops producing thyroxine and as a result the amount of thyroxine in the blood stops increasing and now we have controlled the the amount of thyroxine in the blood so this is how again we can see the feedback mechanism regulates the amount of hormones present in the blood now before we wind up since we are on the subject of thyroid gland I want to talk a little bit about iodine deficiency this might be important for you to remember from your exam point of view now at first you may be wondering where as iodine come from how did the view suddenly why am I talking about iodine how was it important over here well one thing that I didn't tell you earlier is that for the thyroid gland to make thyroxine let me just get rid of the feedback loop for a while so let me just get rid of that it's okay now in order for the thyroid gland to make thyroxine it needs iodine so everytime thyroid gland gets stimulated from the pituitary gland what thyroid gland does it absorbs thyroxine let me just read I don't know here it absorbs the the iodine it absorbs the iodine and then using that iodine it can make thyroxine and then secrete it now imagine what happens if there isn't enough iodine in your body let's say there is no iodine in your body what happens let's see again let's let's work from here the pituitary says hey thyroid start making thyroxine it sends a hormone to it the thyroid says okay cool let's do that but there is no iodine since there is no iron in the thyroid gland is trying to make thyroxine but it can't make so there is no thyroxine and as a result the blood tie rocks in level does not increase that message is again fed back to the pituitary right let me just I can put there so that message is fed back to the pituitary the pituitary says hmmm we are the blood thyroxine has not increased okay it starts sending another hormone and say hey thyroid make thyroxine that's it okay cool I need iodine but there is no iodine so it doesn't make thyroxine it doesn't increase the blood Ericsson level and this keeps on continuing and the pituitary keeps on sending stimulating hormones over and over and over again it keeps on stimulating to the thyroid gland now the thyroid you know what happens because of this as the thyroid gland is getting an unusually large amount of hormones the cells of the thyroid gland think hey we need to make a lot of thyroxine and as a result they start swelling all right as a result of that they start swelling now if you're asking me why did this well think of it this way to produce a lot of hormone you need a lot of space think of it that way another result to make that space the thyroid gland thyroid cells starts swelling up these well cells start sending up swelling up sorry and because the thyroid gland is situated in the front of your neck this means the front of your neck starts swelling as well let me show you that okay a situation like this causes the front of your neck to swell and this particular disease is called Gorter so let me just use the same color okay this is called Gorter so what is going it is a swelling of the neck why does that happen because of the swelling of the thyroid why does that happen because of the continuous stimulation from the pituitary and why is that happening because the thyroid is not able to make thyroxine why is that happening because of because of iodine deficiency so Irene deficiency ultimately causes greater now the thing is our body cannot synthesize iodine all by itself and therefore it's important to make iodine as a part of our diet and it's for this reason the salt that we intake today the salt that we use in our food is always iodized salt you may have heard of this in commercials they keep talking about iodized salt why do we do that because salt is a part of most of the diet and as a result this will ensure that most people regardless of what their diet is are going to get enough intake of iodine from that salt and that is the story of ironing so to quickly summarize what's feedback mechanism or whenever a gland secretes a hormone into the blood the message of whether the hormone has done its job or not is fed back to that gland and based on that message it can control the amount of secretion this feedback mechanism regulates the amount of hormones which you find in your blood