today we're going to explore how the heart blood vessels and blood providers with oxygen join rest and exercise hey everyone welcome to the physical educator don't forget to subscribe to the channel for more IB sport science videos teachers check out the test channel for teaching resources so today CB system we're going to start as we always do with the objectives so there is only one objective one meaning that you need to go into detail in the other seven areas there's a lot of describe explain and analyze so therefore we really need to make sure that you learn this in detail not just what each component is you be able to offer an explanation behind each of them that way you're going to access the higher marks so the first two points today are looking at blood the composition of blood and the function of cloth let's get straight into it so when you go to hospital and have your blood taken there's many things that can look at some of the things that can look at irrelevant for us on the IB sport science let's start off with the blood plasma the blood plasma is the liquid substance of the blood it makes up 55% it helps to transport all of the nutrients around the body we have forty five percent roughly of a wreath resides red blood cells that help transport oxygen and carbon dioxide very important within our blood we also have a very small number less than 1% of leukocytes and these are white blood cells that help fight disease and identify pathogens and remove them from the body finally we have thrombocytes which are more commonly known as platelets again less than 1% they help to form clots which prevent bleeding inside our body or also bleeding outside our body and help to form scabs next we need to see how the blood pumps around the body so we're going to the pump itself to the heart we need to learn valves songs and chambers within the heart always remember when learning about the heart that the right is on the left then left is on the right as you look at it on the paper we have four chambers that we need to learn by right atrium and left ventricle and the left ventricle at the bottom chambers left ventricle being the most important we have four blood vessels that supply the heart with blood the pulmonary artery takes the oxygenated blood to the lungs the aorta takes oxygenated blood out of the her around the body a four artery pulmonary vein brings in oxygenated blood from the lungs and the vena cava supplies the heart with the oxygenated blood we also have four valves valves prevent backflow pulmonary valve is at the entrance of the pulmonary artery as it exits the heart the aortic valve is at the entrance of the aorta again as the blood exits the heart tricuspid valve in between right atrium and right ventricle bicuspid or mitral valve in between left atrium and left ventricle a couple of tips for you to remember here whenever you see the word pulmonary remember lungs whenever you see the word artery remember that it's going away from the heart so it's taking blood away and look how the word vainly spelt in so blood is coming into the heart so pulmonary arteries taking blood away from the heart towards the lungs pulmonary vein is bringing blood into the heart from the lungs a autre away from the heart vena cava into the heart and they are our vessels chambers and valves remember them learn them as best as you can repeat repeat repeat however when you learn them you'll see them in a diagram thankfully not as complicated as this but you will see this diagram and this is what you need to remember please note with this diagram before you pause it that there is also a coronary artery as well which provides the heart with his own blood supply so therefore it's got oxygen to allow a contraction to take place so you do need to remember the coronary heart artery as well now we know how the heart works we need to know how it circulates blood around the body and these two circularity networks for us to explore so our two circulatory networks work together but when learning them in separation they've got some similarities they start at a ventricle they end at an atrium they send blood to either a body system or to the lungs and they're either carrying oxygenated of the oxygenated blood we're going to start with the pulmonary circulation as we've already discussed that word pulmonary is related to the lungs so the pulmonary Network starts in the right ventricle the pulmonary artery takes the oxygenated blood to the lungs to become reoxygenate it does that by gas exchange now at the lungs we have oxygenated blood it returns to the heart via the pulmonary vein and enters through the left atrium that is where the pulmonary circuit ends we then enter the systemic Network which is dead easy to remember it's called systemic because it's the body systems so as the blood leaves the left ventricle it goes through the aorta and they oughta takes oxygenated blood all over the body it's the biggest blood vessel in our body and it takes oxygenated blood to the muscles the digestive system wherever is required for our sake let's just say muscles once the oxygen has arrived in the blood it then diffuses again aerobic respiration takes place carbon dioxide is diffused into the bloodstream we now have the oxygenated blood that means to return to the heart and bill so through the vena cava and it enters through the right atrium once this happens this systemic network is now over and it can return back into the right ventricle and go through the pulmonary network once more and these two circulatory networks work hand-in-hand in this way to provide us with oxygen and carbon dioxide different times oK we've learned the Chamber's we know the heart contracts and relaxes we're gonna look at how that happens from intrinsic and extrinsic regulation of the heartbeat so what it means by intrinsic regulation of the heartbeat is within the hi itself so the SA node is responsible for atria contracts at the same time although it's only located in the right atria the ventricle contraction is via the Purkinje fibers these are the intrinsic factors so as we know the heart is myogenic it creates its own impulse and the hurt has its own pacemaker known as the SA node you can see in the top right hand corner sending the impulse down into the AV node which is in the middle but at the bottom of the right atria the AV node slows the impulse allowing the atria to complete the contraction once this contraction is complete the impulse can be sent down the scepter of the heart down the middle via the bundle of hiss this then branches left and right into the ventricular walls to the Purkinje fibers to allow the ventricle to contract this just continues to happen when we exercise or when adrenaline is secreted by the adrenal medulla this directly affects the SA node increasing the impulse increase in the heart rate that's our intrinsic factors to regulate in our heartbeat extrinsic factors come from the autonomic nervous system and we have the sympathetic and parasympathetic nervous system also known as the fight-or-flight response for the sympathetic nervous system or the rest and digest for the parasympathetic nervous system one of them prepares us for combat the other one reduces and brings back down to a resting state so our sympathetic nervous system increases our heart rate also by adrenaline being secreted onto the SA node our parasympathetic nervous system decreases heart rate acetylcholine is the hormone that's released and this brings the heart rate back down to normal within the lungs the bronchial aches during the sympathetic nervous system stimulation this allows more air into the bronchial for more oxygen into the lungs so again we're ready to fight or flight whatever the situation is that we have to face the parasympathetic nervous system once again just does the opposite what it does is it allows the brawn key to restrict not allowing as much air in bringing back down to a normal breathing stay lastly something else was too so there is the digestive system with all of the stitch before when we exercise the digestive system is restricted with blood flow therefore the priority for the blood flow is to go to the heart and set the muscles therefore we can fight or flight like it like it's suggesting with the sympathetic with the sympathetic nervous system the parasympathetic nervous system will provide the digestive system with blood therefore you can digest and rest as it states the main thing for us to know here is about the heart rate regulation but it's also important to know the impacts of the sympathetic and the parasympathetic nervous system adrenalin also has an impact on glycogen and lipid breakdown for energy production so adrenaline has many many purposes and it's important that we're aware of this so we know the full implications of the autonomic nervous system and remember this is extrinsic regulation of the heart because it's not in the heart itself this is taking place in the central nervous system and it impacts the heart the intrinsic regulation is the SA node AV node bundle of his-- akin survivors in the conviction system conducting our heart beats curry account poor stroke volume and heart rate three terms you're probably familiar with from GCSE PE or biology now we need to look at the relationship between the three during rest and during exercise so as you will have learned during GCSE P in biology days heart rate how many times your heart beats per minute stroke volume how much blood is ejected from the heart per beat switch the stroke each heart stroke and then cardiac output is these two things together heart rate multiplied stroke volume equals our cardiac output therefore it's the amount of blood that leaves the heart minute this is the relationship between the three HR times SV equals Q you can also see Q as Co I like to do Q so you don't get C all mixed up with carbon dioxide what we need to explore with this is not only the relationship in this equation but also what happens is drawing exercise now a media exercise it all goes up your stroke volume increases your heart rate increases therefore you can take output must increase and this is because of the increased demand of oxygen everything increases to provide that oxygen to the working muscles so you can keep respiring you can keep producing energy and keep moving it's when long-term effects on this relationship is assessed where it's a little bit different now long-term effects what that means is you're sat down or standing after six weeks of a training program what has changed within your heart so you're not actually exercising when you consider these effects the immediate effects you just think about standing up and sprinting for 30 seconds the long-term effect is a little bit different it's the adaptation that's taking place within your body over a six-week training program a three-month training program whatever it may be now correct outputs slightly increases some people say it remains quite constant which it does but it does slightly increase there is a slight increase there it's the relationship between her rate and stroke volume that changes here and I'm going to start you with stroke volume one of the adaptations that you should be familiar with is that your heart experiences strength as part of aerobic training as part of cardiovascular training therefore is bigger and stronger cardiac hyper trophic if it's a bigger stronger muscle each contraction can be more forceful therefore your stroke volume increases now if cardiac output is almost the same or just a little bit increased yet the stroke volumes gone up a lot these less pressure on the heart is less demand on the heart to beat as often your heart is more efficient therefore your heart rate can decrease this isn't only at rest your heart will also beat less joint exercise because you'll be more efficient at providing the muscles with oxygen therefore there is less need for it to be as many times this is the relationship between stroke volume heart rate and cardiac output the stronger a stroke volume the less pressure on heart rate because cardiac output needs to be kept constant needs to be maintained and this is how you do it [Music] so cardiac output heart rate and stroke volume could affect different populations at rest and joint exercise so there's three different population groups that we need to look at males versus females trained versus untrained and young versus old the trained and untrained and the males and females are quite similar with regards to the fact that the stroke volume is slightly higher for the male's slightly lower for the females this is just based on the fact that on average if you had a hundred males 100 females next to each other the males would be bigger therefore they'd have a bigger heart therefore it would produce a bigger stroke volume because of the increase in stroke volume there'd be less pressure on the heart for the heart to beat so therefore the heart rate would be slightly lower than the females cardiac output is also slightly higher for the males again just because of the sheer size of a male compared to a female a trained against an untrained athlete is a similar scenario but for different reasons this isn't based on genetics and just basic physiology this is based on a patient's that take face are trained athlete will have a much stronger stroke volume than an untrained utley and this is because of cardiac hypertrophy once this is experienced and klarik output remains quite constant there is less pressure on the heart again so therefore the heart rate can be lower both at rest and your in exercise Kerik output can reach higher levels for a trained athlete particularly during exercise as they have a more efficient cardiovascular system and finally we need to look at the young and the old example this one's a little bit different the resting heart rate for a younger person will be lower than the resting heart rate of an older person be slightly higher again on average however drawn exercise the heart rate increases for the young person much more than it does for the older person giving the older person a smaller range for exercise therefore the intensity can't reach the same levels the stroke volume is stronger for the younger person because their heart is stronger as you get older your heart loses strength just like the rest of your body therefore there is less strength in each contraction cardiac output again reduces with age just like everything else for the younger person the correct output will be slightly higher make sure that you go over these three population comparisons there's no need to go to look at anyone else these are the ones that the IB require these are the ones you need to study in more detail and finally two point two point eight is looking at a phenomenon called the cardiovascular drift quite difficult concepts so let's look straight into it so cardiovascular drift is basically a thermal regulatory response to prolonged exercise so when the body enters a state of dehydration and this dehydration comes about either in excess of heat and it come on quicker or just by the fact that your body heats and produces heat as you exercise so if you're not familiar with cardiac output stroke volume and heart rate do not try and learn about cardiovascular drift go back to them three items in isolation learn them understand them then come back to cardiovascular drift to ensure you know how it works we're talking about submaximal exercise and we're talking about exercise in excess of thirty minutes the three graphs you can now see refer to what happens within the first ten minutes of exercise as you can see a heart rate increases in line with intensity that's always happening through our exercise the stroke volume in the cardiac output start to plateau during submaximal exercise and this is what's important to note when you exercise that there is a plateau however this plateau gets affected by something called the venous return now the venous return is the amount of blood that returns to the heart per minute and that's what's getting challenged when we dehydrate Wailord plasma is lost to the skin and then it leaves the skin through sweat therefore there is less plasma in the blood less blood going around the body therefore more strain on the heart so what actually happens during cardio vascular drift I put it into a little flow chart for you because I think this is the easiest way for you to understand it particularly if you get asked cardiovascular drift question and it's worth five or six marks you can break these points down so heat is produced as a byproduct of energy so when we create ATP we break it down into ADP plus P and Korea energy heat is a byproduct that is released this increases our core temperature to 40 degrees during exercise particularly when it goes beyond 30 minutes or in extreme heat this causes the body to redistribute the heat from the internal areas mainly through the blood to the skin basal dilation of the vessels under the skin is responsible for the movement of this heat evaporation occurs at the skin allowing the heat to dissipate on the the fluid and sweat evaporates the body and it cools this causes a reduction in blood plasma increasing blood viscosity in turn reducing stroke volume and venous return this reduction in stroke volume places an increased demand on heart rate to maintain a steady cardiac output remember carrier Calcott is always constant so there's a battle within the body to maintain that constant States this is why we experience a cardiovascular drift you might still be asking what it means by cardiovascular drift so this last graph can really explain what it means by drift as you can see the middle line is the cardiac output and it doesn't change the axis on the left is referring to percentage of change per minute and the cardiac output is a straight horizontal line meaning there is no change throughout the exercise period if you look at the heart rate every 10 minutes that line is increasing it's going for so therefore there is a percentage a positive percentage change of heart rate during exercise but like a stroke volume it goes the other way and these two lines drift away from each other to maintain cardiac output so again to summarize cardiovascular drift it is a response to dehydration over 30 minutes of exercise because you're in a dehydrated state you are losing blood plasma it's a leopard of the heat within your body this reduction in blood plasma it reduces stroke volume therefore to maintain carry account for the her most beats more times to establish that equilibrium of cardiac output and that is the phenomenon of cardiovascular drift good luck with your studies if you're a teacher looking for resources on unit to cardio respiratory system you can visit the physical educator test site and you can pick up respiratory system and the CV system resources in the shop there thank you for visiting the physical educator see you next time