Glucose homeostasis lesson 2, Glucagon

cool right let's think what happens if you don't have access to food for a few days well for a few I get hungry after a few hours you ever decide to fast for a couple of days I think I think I'll just fast a while and then I get hungry enough something to eat focus maybe don't eat for a while then what will happen is all your glucose the glucose in the blood will constantly be used up the glucose in your cells will be used up and the amount of glucose in the blood is going to go down so if you haven't eaten for a while especially be using energy well you use energy all the time especially if you like working out awesome then the amount of glucose and the blue is going to go down and that is detected primarily by the alpha cells so these alpha cells here detect reduction in the level of blood glucose so the beats ourselves were hyperglycemia detectors the alpha cells are hypoglycemia detectors they detect reductions in levels of blood sugar and what the beta cells so what the alpha cells do when they detect is they also release an endocrine hormone release ones called glucagon so the alpha cells release glucagon in response to a developing hypoglycemia when the blood sugar levels drop so now as well as not having a lot of sugar in the blood you'll have glucose on in the blood and glucagon is also an endocrine hormones same as insulin so it circulates around the body and it circulates to actually fortunately remember yesterday when we have plenty of food we produce the load of glycogen didn't we we didn't need it yesterday but now we have an any food so the glucagon will act on this glyco again absolutely yeah because because it's produced by an endocrine gland it's released into the blood it circulates systemically all around the body therefore it's an endocrine gland so the key difference is an exocrine gland is released into a duct like sweat sweat is an EXO triangle and sweat is produced goes into a duct and goes onto the surface of the body or survivor is also an EXO crime product is produced in saliva glands goes out ducts and goes into your mouth this EXO crime absolutely yeah the pamphlet the pancreas is EXO yeah the pancreas is EXO crime because it produces digestive enzymes but it's also endocrine because it produces insulin and glucagon and because the insulin and glucagon are not released into ducts because they are released directly into the blood they're classified as endocrine products endocrine hormones so the glucagon will circulate to the liver and the glucagon will circulate to the muscles and what the glucagon will do is the glucagon will convert the like Oh Jen which restored the glucagon will convert the glyco again back into glucose what is what look like the molecule oh it's just it's just a small molecule that's them well the internet was read well then let's make that one bloom so it circulates around in the book it's Sami blood circulation and denial so in the blood sugar levels drop the lower blood sugar levels are detected by the alpha cells there the hypo detectors the Alpha of cells respond by producing glucagon the glucagon circulates from the pancreatic islets where it's produced by the alpha cells circulates to the liver and muscles where the glycogen was stored and it converts the glyco again back into glucose so it's just the word isn't it no some begin with G so I think don't they so glucagon converts glyco Jen back into glucose glucagon converts glyco Jen back into glucose now this is converted back into small individual glucose molecules and because it's now converted back into small individual glucose molecules because these are small they're highly soluble so they go into the blood and because now we have more small individual glucose molecules in the blood what's going to happen to blood sugar levels it's going to go up isn't it so the hypoglycemia has been corrected by the hyperglycemic effect of the glucagon the glucagon is raising the blood sugar levels absolutely yeah now we've got the individual glucose molecules then as long as the summation about which there will be some insulin about then those glucose molecules can go into the cell be used by the mitochondria to produce energy and that's important because that keeps you going till you can walk to a new food supply yes yes yes no no that no they can never do it on their own always or always because the cell membranes are made of phospholipids and won't let the glucose molecules diffuse through that's in the vast majority of cells actually in brain cells the glucose will go through pretty well on its own well it's also phospholipids but it's got a different nature and it will allow some diffusion of glucose directly so we see that the glucose has raised blood sugar levels now you've probably got oh I don't know about 800 grams of glycogen in the body something like that you check this out lonely - how many how much glycogen just or in the body but eight hundred mils 800 grams something like that probably 800 grams anyway you've got a certain amount of glycogen stored in the body and depending on how much you're working out you've probably got enough for a couple of days please introduce enough glucose where you can liberate enough glucose from stored glycogen to maintain you energy levels for a couple of days and this is actually quite good for Nikoli because if someone's hypoglycemic if someone's 5bo glycemic can you see one way we could treat that is to give them something to eat isn't it you can give them some will be give them a mars bar or something would give them something to eat or give them a drink of coke or lucozade all these things contain huge amounts of sugar but if someone's unconscious because they're hypoglycemic so if someone is hypoglycemic the probably become confused first that they become unconscious and at some point after that they're at risk of dying so can we give them unconscious patients drinks of lucozade because it will go down into the Kia that causes a condition called aspiration pneumonia which is that always kills you one always kills so if you see the patients unconscious we can't do that now that's fine in hospital we can put a intravenous line in and we can run some dextrose solution directly into their bloodstream we give some intravenous Lugo's of dextrose would normally give give intravenous trigger if someone has a hypo in the carpark you probably haven't got a drip on your hub you can do on your awesome intravenous dextrose on it so what diabetics often carry is they'll carry a little injection which we give intramuscular II of glucagon so if someone's hypo you can give them an intramuscular injection of glucagon which is easy and that can be enough to wake them up that will release enough sugar from stored glycogen to wake them up and then when they're awake then we can give them something to recover and get back to normal that way if someone's hypoglycemic right and they're unable to eat and we can't we can't give them intravenous sugars because we're now in hospital then we can give them intramuscular injections of glucagon glucagon and the glucagon will increase the blood sugar levels wake them up so we can give them something to eat now suppose we're in a really difficult time and we haven't found any fruit or vegetables and we haven't had any antelopes killed by the tribe for a few days and we haven't eaten for two three four days can you see we're going to run out of stored glycogen does that make sense we're gonna run out of store glycogen but we need a certain amount of glucose in the blood otherwise the drains not going to work otherwise the drains going to die isn't it so we're okay for a couple of debbie's that's fine if you're gonna have food for longer then we've got a problem but fortunately fortunately what we got in here no over here underneath your right costal margin yeah remember your livers underneath your right costal margin isn't it thunder there was something in what's at the top of the tummy on the left-hand side stop the other one on the Left I'm sorry that's the spleen isn't it so it's liver their spleen their head body tail of the pancreas there so you've got your liver under there so what will happen in this situation if you haven't eaten for a few days is the glucagon will go to the liver but the glucagon goes to the liver and one of the things the glucagon will do quite very astute glucagon no quite right actually glucagon then yeah so the glucagon goes to the liver and what happens is the glucagon stimulates a process called gluco neo Genesis gluconeogenesis gluco means glucose neo means new and Genesis means beginning so the glucagon can actually make a certain amount of glucose by breaking down fats and proteins it's not a brilliantly efficient process it's a bit slow but the gluconeogenesis can use fats and proteins to make more glucose so initially the glucagon will maintain blood sugar levels by breaking down glycogen that breaks down the glycogen from the liver and the muscles but because because you only store so much but if there's still no food after 2 3 4 days then the glucagon will stimulate the liver to make glucose but it will make it from fats and proteins using this process called gluconeogenesis so can you see that means that the glucagon is still raising blood sugar levels days after we haven't days after the last time we've eaten yeah no no good question if someone hasn't eaten for a few days and you smell the breath it smells sweet because it contains something called acetone and acetone isn't is one of what we call ketone bodies so if someone hasn't eaten for a while as well as making a certain amount of new sugar from gluconeogenesis to keep the brain going the glucagon will actually also stimulate the liver to produce ketones yeah keep the juice ketones so ketones are this smelly acetone type stuff plus ketones there's two assists to organic acids and ketones but they are energy rich assets they can be used as a fuel supply so in starvation the glucagon will maintain blood sugar levels for weeks by converting stored fats and proteins to glucose that's gluconeogenesis but also the glucagon sorry yes also the glucagon will stimulate the liver to produce ketones its ketones that gives that acetone II type smell the ketones also use for energy and we can run on ketones of our energy supply until we run out of fats to make the ketones frog yeah well you can't take you can't take keep you can yeah yeah right so if if you can't if you know access to food the glucagon will go to the liver the liver will convert fats into ketones so when someone is hungry lots of ketones are going to be released from the liver into the blood and the ketones can be used by most cells and as an energy supply right well if someone's got ketones if someone's got ketones in their blood then those ketones will leak out of the kidneys in the urine so ketones in the blood keto emia will resorting ketonuria you'll get ketones in the blood and what that means if someone's got ketones that means that Luke had gone has stimulated the liver to make the ketones but that will only happen if the blood sugars been low for a long period of time yeah well yeah so one thing it might mean is the patient is hungry because they haven't eaten for a long period of time so in starvation you'll get a ketosis but also remember thinking rubbed it off now remember then here we have this cell we have a cell that's the cell there's the mitochondria inside now if there is a if there's no if there's no if someone's starving right the starving then there's no sugar to get into the mitochondria and in the liver that means that the liver cells will start producing ketones because there's no glucose inside the cell but also remember in type 1 diabetes for the glucose to get into the cell we've got the insulin receptor but we have to have the insulin it's only when we've got the insulin and the insulin receptor that the glucose is going to be gated into the cell so if there's no glucose because someone's got type 2 diabetes if there's no glucose you see as far as the mitochondria is concerned the situation is exactly the same it can't make it's not getting any glucose so the liver cells if they're not getting any glucose they're going to respond by producing ketones so that's the irony of diabetes you've got loads and loads of sugar molecules outside in this case outside your liver cell millions of nervous but because they can't get through the membrane then as far as the mitochondria inside the liver cells are concerned this patient is starving they're not getting any glucose so the mitochondria another the cells won't get glucose if the patient is fasted or starving but also and therefore will produce ketones but also if the patient has type 1 diabetes the nerve there's no insulin getting through therefore the glucose outside the cell can't get in therefore the mitochondria in the liver don't have any glucose and when they don't have any glucose they start producing lots of ketones no no ketones are produced primarily in type 1 diabetes yes now in type 2 diabetes the reason is that type 1 diabetes is an absolute deficiency of insulin you get no insulin at all if you've got no inch lip of tall then you're gonna get ketone formation but in type 2 diabetes the amount of engine it might be reduced but you've always got a little bit of insulin and the thinking is that in most cases of type 2 diabetes there's enough insulin to prevent ketone formation just having said that very rarely some type 2 diabetics might get a bit of ketosis but basically if we find ketones that means its type 1 so a what good way of a patient submitted with diabetes we just test the urine for ketones and if there's ketones then you're pretty safe in saying that's the type 1 diabetes if there's no ketones but the patient still hypoglycemic then that will be a type 2 diabetes fix wall all right line drive I like so what you're saying is that insulin diabetes is caused by insulin deficiency and if we give anything why doesn't that cure everything okay yeah yeah yeah right if if people develop type 1 diabetes and the insulin is not available then they will die within months they'll die quickly they'll die from the short term complications of the time line but if we give the insulin then they won't die from acute hyperglycaemia in ketosis they won't die from ketoacidosis and hopefully they'll be well for many decades but people with type 1 diabetes do have a shorter life expectancy than people without diabetes and the reason for that is primarily they get diseases of their blood vessels and they get diseases of the blood vessels that go to the heart and the brain so they're more prone to coronary artery disease and cerebral vascular disease but they also get other complications like infections damage to their peripheral nerves and damage to their kidneys so the most common cause of kidney failure in the UK at the moment is in fact diabetes so the answer is to get long-term complications of diabetes more frequently than other people the average at the UK at the moment is that after someone's been diagnosed with type 2 diabetes the technically need injured in about 7 years after their diagnosis so I say we look till we give it when we need to right you see what don't hurt me Oh stasis we've done what happens if the blood sugar level goes too high the insulin is produced if the blood sugar level goes too low the glucagon is produced in the short term the glucagon will liberate glycogen to maintain blood sugar levels when the glycogen is used up the glucagon will stimulate the liver to produce some fresh glucose some new glucose in this process called gluconeogenesis but longer term the glucagon will also stimulate the liver to produce ketones and the ketones will keep you alive as long as you've got some fats to utilize so if someone's really quite obese in fact that what there was someone wants someone to try this but there was someone who was remarkably obese and some nurses got all them they put him and they put him in a roof basically put in Tibet because it was morbidly obese then it gave him lots of drink and gave him vitamins and they didn't feed him for a whole year unbelievable and you know he didn't die I won't recommend that Rudy but you know he had a year's supply of energy you know he must have been massively obese but for most people now most average people can live our problems that you can live without eating at all it depends how much fat you've gone cuz it also depends how much muscle you've got because the muscles broken down to make energy as well I'd say most of you would be feeling pretty rough after 60 days of not eating okay papi died about 60 days yeah just a minute just me couple of questions and we will have a chat yeah yeah well it depends how much water you're using you know if it's a hot environment you can dive within 48 hours you know if someone locked us in this room now we'd probably last for about a week so it depends how much is going out it's an energy balance thing isn't it now children of course children of course are going to run out of energy much quicker than adults so neonates don't have a lot of fat storage typically so babies need fed pretty well straight away after they're born and throughout childhood most children are actually quite thin they don't have a lot of spare adipose tissue so children need fed on a much more regular basis that can get my nutrition really quite quickly they can get protein energy malnutrition and they can get particular types of malnutrition due to deficiency of specific nutrients as well and of course children are more prone to dehydration as well because they've got lower blood bonds oh good I don't explain glucagon mechanisms to each other

Channel: Dr. John Campbell

Views: 12,930

Rating: 4.9619045 out of 5

Keywords: glucagon, glucose homeostasis, diabetes, ketones, gluconeogenesis

Id: ViK9ZSWviZw

Length: 28min 36sec (1716 seconds)

Published: Tue Mar 18 2014