Exercise Physiology Exam 3 1 Here is a review of the anatomy of the heart in case you need it The heart is a main organ in the cardiovascular system as well as the body It has four chambers that work together to supply blood to the body The two upper chambers are the right and left atrium and the two bottom chambers are the right and left ventricle Since the pathway is a loop we will pick one spot to start at Deoxygenated blood enters the right atrium from the inferior and superior vena cava these return blood from the lower and upper half of the body then the blood passes the tricuspid valve into the right ventricle The right ventricle then pumps the deoxygenated blood to the lung by the pulmonary artery the allow artery that carried deoxygenated blood After it is oxygenated it enters the left atrium by the pulmonary vein only vein to carry oxygenated blood passes the mitral valve and flows into the left ventricle Then it is pumped out to the body this ventricle is much thicker since it has to pump to the whole body The blood leaves the heart in arteries goes to capillaries and then once it is deoxygenated flows back to the heart in the veins The process then repeats Heart and Lungs 1 What are the expected training effects from aerobic exercise on HR SV and Q First we will define some terms Heart rate is how fast the heart beats every minute stroke volume is the volume of blood that the left ventricle pumps with every beat and cardiac output is the total amount of blood that the heart pumps every minute equal to HR x SV With questions like these about the effects of training on some value it will be easier to setup a comparison of the pre training state and the post training state So let s take someone before they enter an aerobic schedule Their resting heart rate is probably around 70 75 normal SA node rhythm their stroke volume will probably be around 110 ml and their cardiac output at will be 5 L min at rest Then once they start exercising their heart rate will increase fairly quickly at a certain intensity up to their max heart rate their stroke volume will increase due to the demands of the exercise and their cardiac output will increase to around 15 20 L min Tony Berardi 2 Now let s look at a well trained runner Their resting heart rate will be much lower due to the greater vagal tone this is parasympathetic input so probably around 40 45 As a result of the low resting heart their stroke volume will be greater at rest The cardiac output is the same at 5 L min cardiac output is the same for everyone AT REST Then once they start exercising their heart rate will increase much slower compared to the unfit individual So at the same intensity of exercise of the unfit their heart rate will be much slower meaning that their body is working less to maintain the intensity With heart rate though the thing you have to understand is that max heart rate will never increase This decreases with age via 220 age and no amount of training will increase it The fit athlete will reach it at a much higher intensity than the unfit but this number does not change Stroke volume will much substantially higher with training and cardiac output will also be much greater So depending on what he is asking resting heart rate decreases with training heart rate at any given intensity will be lower in the trained athlete but regardless of training max heart rate will not change SV will be greater at rest and during exercise CO will be the same at rest it is always 5 6 L min at rest unless there is some coronary heart disease present and it will be substantially greater with the trained athlete Think that their heart which is a muscle so it gets stronger and bigger just like any other muscle can pump more blood with every beat because it is stronger 2 How are the electrical impulses passed through the heart What are the physiological events associated with the beat of the heart First to explain the anatomy of the heart The heart is a main organ in the cardiovascular system as well as the body It has four chambers that work together to supply blood to the body The two upper chambers are the right and left atrium and the two bottom chambers are the right and left ventricle The atria are the upper chambers that are essentially blood reservoirs for the ventricles which pump the blood out Since the right side of the heart propels blood to the pulmonary circuit lungs and the lungs are very close to the heart the right ventricle is not as muscular and strong as the left ventricle The left propels blood throughout the systemic circulation whole body so it is much more muscular and stronger The SA node is the main pacemaker in the heart and this usually determines heart rate as it beats regularly at 60 100 BPM This node is in the upper area of the right atrium During a heartbeat the SA node will conduct an AP which will travel throughout the heart to cause contraction of the Tony Berardi 3 myocardium Think of the heart of one muscle when one cell gets depolarized and contracts they all do The pathway for the conduction system is as follows The SA node conducts an AP and this will spread to the left atrium via fibers that you don t need to now Then it will reach the AV node and the signal will actually stop here for a second to let to ventricles fill with blood completely After the atria have contracted the signal will then travel down the bundle of His and slit to the right and left bundle branches to their respective ventricles Then it will travel down the purkinje fibers to depolarize the back of the heart So it has thus spread from the SA node at the top of the atrium to the bottom of the ventricle 3 Understand these relationships at rest during sub maximal and maximal exercise a b Q HR x SV Q VO2 a vO2 diff c VO2 Q x a vO2 diff d Q P R Equation A is the formula for cardiac output Heart rate in BPM is multiplied by the stroke volume in ml to get the cardiac output in either L min or ml min This number is the total volume of blood that the heart is pumping out every minute so a greater number is beneficial to aerobic exercise At rest everyone has a cardiac output Q or CO of around 5 6 L min The values that change with training are the HR and the SV Training will lower ones HR at rest and raise their SV to maintain that 5 6 L min During submaximal all these values will increase SV will increase …
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