Exam 2 Study Guide: APK3110c: Applied Exercise Physiology
Exam 2 Study Guide: APK3110c: Applied Exercise Physiology APK3110c
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This 29 page Study Guide was uploaded by Courtney Adams on Tuesday October 27, 2015. The Study Guide belongs to APK3110c at Florida State University taught by Dr. Robert Moffatt in Fall 2015. Since its upload, it has received 438 views.
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Date Created: 10/27/15
Physiology of Exercise Review Guide Exam ll October 29 2015 Chapters 12 13 1517 20 lab and lecture notes 1 Know what factors explain a high percentage of fat use at low intensities with a low use of carbohydrates and the opposite occurring during high intensity exercise Rest Aerobic Glycolysis Beta oxidation using a mixture REST FAT CHO Aerobic Metabolism HLA 10 mgdl small amount of all three fuels CHO protein plays a small amount and fat a mixture of 4060 fats vs carbs seems like there will be NO lactate produced but in reality there is some lactate being produced 10mg per 100 mL of blood always some leaking in the system so it does produce SOME lactate primary source of fuel FAT Light to Moderate Exercise Long Duration exhausted in 60 minutes submaximal intensity rst anaerobic until it reaches 2 3 minutes in then turns into aerobic metabolism fat is used as a fuel steady statequot suggest that the de cit may in fact disappear during that long submaximal effort Heavy Exercise Short Duration exhausted in 2 minutes maximum intensity sprinted as hard as you could ATPPC Anaerobic Glycolysis some aerobic contribution under this condition you will never ever just get aerobic metabolism supporting that 2 min worth of max intensity carbohydrates in the form of muscle glycogen will use the energy stored ATP very quickly you will use the energy stored in CP to make more ATP very quickly and you will depend on anaerobic glycolysis to provide energy that is released by the derogation of blood glucose from muscle glycogen also very quickly And as time goes on you will have a little more contribution from aerobic metabolism The once we start to reach hard and maximal exercise our body shifts to using carbohydrates for fuel Even though fat produces much more ATP than carbohydrates carbohydrates are preferred Carbs are superior when oxygen is limited i The longer the event the more aerobic the event will be SHORT DURATIONMAX ENERYGY ATPPC and CH0 glycogen Anaerobic some aerobic HLA 175 mgdl Absence of oxy is the main A A1A111A A1 2 Know the two general ways hormones signal physiological and metabolic changes in the body eg differences between lipid soluble and lipid insoluble signaling 0 There are two classes of hormones lipid soluble and lipid insoluble o Lipid soluble or Steroid Hormone Made from cholesterol Diffuse through membranes right into the cell and act directly on a receptor near the nucleus Once bound to the receptor it can act directly on the DNA to regulate mRNA synthesis Secreted by four major glands Adrenal cortex ovaries testes placenta Ex testosterone aldosterone cortisol and estrogen o Nonsteroid Hormones Not derived from a steroid Cannot cross membranes Act through a second messenger system receptors are on the cell membrane Divided into two groups Peptide protein hormones 0 Most nonsteroid hormones insulin and glucagon 0 From pancreas hypothalamus pituitary gland Amino acidderived hormones o Thyroid hormones T3 T4 0 Adrenal medulla hormones NE Epi 3 A Be able to describe how catecholeamines raise blood glucose levels 0 Both catecholeamines and glucagon have hyperglycemic effects increasing blood glucose levels 0 Stimulation of gluconeogenesis o Stimulate glycogenolysis o Antagonize insulin Epinephrine o The majority of the catacholamines that the body releases during exercise around 80 of the total 0 We should all be able to see this since epinephrine is also called adrenaline and we know adrenaline is always releases during exercise 0 Heart rate blood pressure glycogenolysis and lipolysis all increase 0 Epinephrine will stimulate glycogenolysis to occur in the liver and the muscles thus increasing blood glucose levels to raise blood sugar 0 Epinephrine acts to increase glycogen breakdown Insulin o Lowers your blood sugar by causing glucose to enter the cells 0 When you want to raise blood sugar the catecholamines and glucagon the other hormone released by the alpha cells in the pancreas accomplish this 0 They do this by stimulating glucoeogenesis to make glucose from nonglucose molecules glycogenolysis breakdown of glycogen and to inhibit insulin only glucagon does this meaning that the two hormones of the pancreas do opposite things One raise blood sugar glucagon and the other decrease it insulin B How catecholeamines increase fat metabolism during exercise 0 The catecholamine response to exercise by stimulating lipolysis of triglycerides In addition increases in adipose tissue and muscle blood flow decrease fatty acid reesteri cation and facilitate the delivery of released fatty acids to skeletal muscle 0 Acute endocrine responses during exercise which result in changes to hormone secretion primarily serve to meet the physiological demands imposed by exercise stresses 0 Response and function during exercise 1 Vascular function for muscle blood flow 2 Fat metabolism 3 Glucose metabolism 4 A Know the two different receptors they work through 0 Beta 0 Stimulateslipolysis o Vasodialation o Epinephrine binds to these receptors to stimulate lipolysis fat break down via the enzyme hormone sensitive lipase and that second messenger system 0 At LOW EPI levels eg REST the Breceptors will be primarily bound because EPI has a higher af nity for these receptors Thus the predominant effect at low EPI levels is vascular smooth muscle relaxation vasodilation Alpha 0 Inhibits lipolysis o Vasoconstriction oAt HIGH EPI levels eg EXERCISE the dreceptors will be primarily bound because there are more of these receptors Thus the predominant effect at high EPI levels is vascular smooth muscle contraction vasoconstriction o Epinephrine inhibits it 0 Beta cells what we need for exercise 0 Beta 1 gycolysis 0 Beta 2 vasodialation B Know how caffeine and green tea enhance catecholeamine signaling 0 The study compared green tea with caf nee 0 Green tea and Caf nne showed NE in urine and increaed energy expenditure 0 Induces the lypolytic pathway 0 Green tea extract 0 Inhibits the enzyme that works to break down the epinephrine 0 So it binds to the beta receptor longer to cause increases lipolysis o This enzyme that it inhibits is called COMT 0 Green tea impares the degragation of NE which causes it to be around longer Caffeine 0 Causes the same effect but through a different mechanism 0 Works to inhibit the cAMP degrading enzyme so that the cAMP s can keep on causing Iipolyis o This enzyme is called PDE o Caf nee stimulates NE release l which stimulates the beta receptor to increase heart rate increases energy expenditure end up burning more calories 0 Conclusion O O 0 Would taking both maximize fat loss over the long run One does indeed signi cantly increase lipolysis but it is maximized within a day Meaning it works but it is an acute effect and doesn t cause more and more fat loss with time The take away message is that exercise leads to weight loss and increases your insulin sensitivity 4 Be able to describe the effect of glucagon on the Cori cycle and what factors cause stimulate its release Glucagon is the antagonist of insulin 0 O O O O Glucagon upregulates the Cori Cycle Works to raise our blood sugar by increasing the rate of glycogenolysis and gluconeogenesis Glucagon released from the alpha cells in the pancreas Serves to raise blood glucose Gluconeogenesis will increase and glycogenolysis will increase It will also increase fatty acid breakdown by stimulating the enzyme HSL hormone sensitive lipase T Glycogenolysis gluconeogenesis Increases glucose in 3 ways 1 Gluconeogenesis 2 Glycogenolysis 3 Antagonizes insulin Glycogen is the storage form of glucose and during exercise it is broken down as fuel is needed 0 During exercise the release of epinephrine will stimulate the muscles to breakdown muscle glycogen This is hormonally mediated since epinephrine is stimulating it Another mechanism is by the Calcium concentration in case he talked about this But epinephrine is the main one It turns on the enzyme that breaks down the glycogen B Describe insulin s actions and general response to exercise Insulin O O O 0 Released from the beta cells in the pancreas Lowers blood glucose Stimulates all of the cells to absorb glucose Causes glucose to enter the cells so the cells can break down the glucose for energy Stimulates the GLUT 4 receptor to translocate come to the surface OO This lets glucose enter the cell Exercise will also cause this to happen Stimulate glycogen synthesis since this will lower blood glucose level it will promote triglyceride synthesis and protein synthesis Insulin is mainly an anabolic hormone it will increase synthesis of most everything Insulin in inhibited during exercise T Glucose transport into cells T Synthesis of glycogen protein fat Inhibits gluconeogenesis C Be able to describe the role of thyroid hormones and growth hormone in fat metabolism and growth hormones effect on carbohydrate metabolism 0 Growth hormone O O O O O O Stimulates protein synthesis and lipolysis fat breakdown Suppresses carbohydrate metabolism A major anabolic hormone Responsible for building tissuebone and promoting hypertrophy Increases fat metabolism It has been shown to rise proportionally with exercise Thyroid basal metabolism 0 Permission its presence allows other hormones to do its job Allows growth hormones to do its job Affected by increase in temp TH increase Exercise will stimulate the release of TH Exercise in uences Thyroid chronically more than acute 0 You will see an increase 7 Know how cortisol increases gluconeogenesis and understand its role in overtraining whole body protein breakdown Cortisol O O Stimulates amino acid release from the muscles during prolonged exercise So cortisol will work to provide your body will more glucose for fuel It will do this through glucoeogenesis Known as the stress hormone as our body releases it during stress Increases with exercise intensity higher intensity means a higher stress for the body 0 When released it will cause gluconeogenesis increase fatty acid mobilization and increase protein catabolism o In extreme instances it will cause protein breakdown which can also be used to form glucose 0 So this is what happens when you hear that stress makes people fat When you are not exercising and you are stressed you release cortisol Your body will increase its glucose stores because it thinks you need energy If you have an increase of glucose when you are not breaking it down it will be stored as fat 0 Training preseason vs season 0 Look at level of corisol and testosterone vs V02 0 Too much cortisol indicative of overtraining breaks doen muscle impairs performance 8 Know what hormones effect uid regulation and blood pressure regulation during exercise with particular attention to angiotensin 2 aldosterone and ADH s role in uid regulation 0 As one exercise they lose sweat right Sweat is water so as exercise intensity increasingly causes one to sweat more they get dehydrated Blood is also mostly water so as you get dehydrated your blood volume also decreases this lowers your blood pressure And we don t want that to happen so our body needs a way to counter this effect 0 Our body releases certain hormones to counteract this uid loss 0 Being released from the posterior pituitary the adrenal cortex and the kidneys these hormones work to correct uid balance 0 The posterior pituitary o Releases the hormone ADH 0 Works to increase uid level by causing the body to reabsorb water from the kidneys The ADH will travel to the collecting ducts in the kidney and signal the body to reabsorb more water This is the urine before it leaves the body so since more water is being reabsorbed the urine will be more concentrated with solutes This will then increase the uid in the body 0 ADH o A stimulus is a lower plasma volume this tells the body that it needs more water so it will act by releasing ADH O Increases osmolality means the same thing technically means there are many solutes in the blood compared to water Aldosterone 0 Released from the adrenal cortex in response to a low plasma volume of sodium a low blood volume or a high plasma level of potassium This indirectly causes the same plasma volume increase as ADH but through a different mechanism The pathway for how aldosterone is signaled to be releases actually starts in the kidneys with a molecule called Renin Renin travels to the lungs and activates an inactive enzyme called angiotensinogen to angiotensin 1 This is then cleaved to angiotensin 2 via the ACE enzyme The nally angiotensin 2 causes the release of aldosterone and aldosterone cause more sodium to be absorbed from the collecting ducts of the kidney Then via osmosis water will follow the sodium so blood plasma increases Angiotensin 2 O O 0 Extreme vasoconstriction Increase the blood pressure This is how ACE inhibitors work they inactivate the ACE so that angiotensin 2 can t be formed so there is no vasoconstriction and thus no increase in blood pressure 9 What are the expected training effects from aerobic exercise on HR SV and Q 0 Heart rate how fast the heart beats every minute 0 0 Heart rate is one of the two primary determinants of Q which rises linearly with work rate The gradual withdrawal of vagal parasympathetic nervous system in uences and the progressive increases in sympathetic nerve activity which occur during exercise are largely responsible for the observed increases in HR At or near V02 max HR begins to level off and is referred to as maximal heart rate The equation 220age provides a rough estimate of an individual s maximal heart rate with standard deviation of 1012 bpm As implied the maximal heart rate will decline with increased age As work increases HR increases to deliver more oxygen to skeletal muscle At maximum of 20yo HR200bpm After several months of training there will be an increase in max cardiac output lower resting rate and an overall decrease in response Training not only increases hemoglobin levels but is more of a physiological response During submaximal effort anything less than max it will decrease as well NEVER an increase in max HR Stroke volume is the volume of blood that the left ventricle pumps with every beat 0 Stroke Volume is the other primary determinant of Q and represents the amount of blood ejected from the heart with each beat Unlike HR Stroke Volume does not increase linearly with work rate SV increases progressively until work rate equivalent to approx 40 V02 max is reached Thereafter continued increases in work rate cause little or no increase in SV Exercise induced increases in SV are believed to be the result of factors that are both intrinsic and extrinsic to the heart According to the Frank Starling Law a greater stretch placed on the muscle bers of the heart due to greater venous return of blood to the heart during exercise resulting in a more forceful contraction of those bers and consequently a greater SV Extrinsic factors such as increased nervous sympathetic or endocrine release of adrenal hormones EPI amp NE stimulation to the myocardium can also contribute to increased SV that occurs during exercise Men 80100mlbeat Women 5060mlbeat Ventricles can only ll so much therefore SV reaches max around 40 of maximal aerobic capacity If overstressed they will stretch and generate less force This is called the Starling Law of the Heart Cardiac output the total amount of blood that the heart pumps every minute 0 Q Cardiac Output the amount of blood pumped by the heart per minute is explained by this term This measure is indicative of the rate of oxygen delivered to the peripheral tissues skeletal muscles Cardiac Output which is the product of HR and SV increases linearly as a function of work rate At rest Q is roughly 45 Lmin but can rise due to the alterations in both HR and SV 0 QHRXSV Now let s look at a welltrained runner Their resting heart rate will be much lower due to the greater vagal tone this is parasympathetic input so probably around 4045 As a result of the low resting heart their stroke volume will be greater at rest The cardiac output is the same at 5 Lmin cardiac output is the same for everyone AT REST Then once they start exercising their heart rate will increase much slower compared to the un t individual So at the same intensity of exercise of the un t 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 220age and no amount of training will increase it The t athlete will reach it at a much higher intensity than the un t but this number does not change Stroke volume will much substantially higher with training and cardiac output will also be much greater 0 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 56 Lmin 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 Summary 0 Resting HR decreases with training HR at any given intensity will be lower in a trained athlete but regardless of training Max HR will not change trained individuals will reach it at a higher intensity Also Max HR will decrease with age 220age SV will be greater at rest and during exercise Q will be the same at rest always 56Lmin unless disease is present and it will be substantially greater with trained athletes The heart a muscle once trained will be bigger hypertrophy and stronger so it will pump more blood with every beat because it is stronger 0 Exercise increases HR due to an increase in sympathetic NE This meets a demand for 02 Parasympathetic activity decreases ACHinhibits Sympathetic activity also increases myocardial contractility increasing the strength of contraction thus increasing SV Due to Starlings Law stretching ventricles causes it to contract more forcibly Venous return can only pump out what you return Cardiac Output drives 02 consumption and therefore a trained heart is more ef cient and improves ability to consume 02 This is also predicated on the amount you can extract 10 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 60100 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 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 bers 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 ll 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 bers 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 0 Physiological P Wave atrial depolarization QRS Complex ventricular depolarization ST Segment Ventricular repolarization A depression here indicates an upcoming heart attack as the heart isn t receiving enough oxygen T Wave ventricular repolarization QT Interval ventricular depolarizationrepolarization 11 Understand these relationships a Q b HRxSV 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 Lmin or mlmin This number is the total volume of blood that the heart is pumping out every minute so a greater number is bene cial to aerobic exercise At rest everyone has a cardiac output Q or C0 of around 5 6 Lmin 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 56 Lmin 0 During submaximal all these values will increase SV will increase at the onset of exercise to accommodate the greater need the muscles have for blood HR will also increase as the intensity increases During sub maximal exercise HR will not contribute the greatest increase to the Q though SV will HR will increase exponentially after 5060 of ones V02 max measure of intensity SV is what will increase greatly before this intensity is reached Then at maximal SV will stop increasing past 5060 of ones V02 max and HR will now increase greatly Since HR is increasing Q will increase Q V02 aVOZ diff An increase in aV02 difference during exercise is due to an increase in the amount of 02 taken up and used for production of ATP by skeletal muscle c V02 Q x avOz diff Equation B is the same as Equation C and I don t like equation B so we will talk about the latter This is the Fick equation for V02 max It is equal to ones Q x av02 difference This is either expressed in units of mlkgmin or Lmin Well Q is equation A so this means that V02 will increase as the exercise gets more intense V02 max is a great measure of cardiovascular health as this is the number of oxygen that the body heart can supply to the working muscles Av02 difference is the difference between the volumes of oxygen is the arteries minus the volume of oxygen in the veins If you recall the circulatory system blood and oxygen travel from the arteries to the capillaries where gas exchange occurs then travels back to the heart via the veins So the amount of oxygen left in the blood in the veins is the amount of oxygen that the muscle did NOT take up meaning a greater av02 difference means the muscles are being more ef cient at using the oxygen 0 For example the arterial concentration of oxygen is around 20 mldl If 5 ml is taken up at the capillaries then the venous concentration will be 15 mild thus the av02 difference is 5 ml Now during intense exercise the capillaries become more ef cient at taking up oxygen so now say 15 ml is taken up at the capillaries Now the venous concentration is 5 ml and the av02 difference is 15 ml With intensity the av02 difference will increase as the body takes up more and more oxygen but this value doesn t really change with training So you can understand the concept of what this number is or just know that a great av02 difference means the capillaries are taking up more oxygen so the muscles are getting more oxygen d QPR Equation D is another formula to get the Q but it is used mostly to get the TPR or the total peripheral resistance R is the total peripheral resistance which is the resistance of the whole circulatory system to blood ow and P is the pressure difference is the systemic circulation The resistance to the blood ow is controlled via the diameter of the vessels This is just a plug and chug as I don t think he wants concepts for the way the circulatory system beats One thing to know during exercise is that the TPR or R as represented in the equation will decrease because the body will lower the resistance to blood ow during exercise so it will increase ow to the muscles If you look at the formula QPR if you decrease R Q will increase which happens during exercise Blood pressure decreases throughout the circulatory system starting around 100 at the heart and going close to 0 once it gets back to the right atrium 12 What is blood ow redistribution and which tissues are affected How Blood ow redistribution is how the body changes the amount of blood that it supplies to different parts of the body during exercise At rest most of blood is shunted to the liver GI tract and not a large percentage is pumped to the muscles mostly because at rest the muscles don t need all the blood to contract Then once exercise starts the brain senses the need for more blood to be delivered to the working muscles and skin to dissipate heat generated from exercise so now the ratio will shift during exercise around 7080 of the blood is shunted to the muscles and more blood than before to the skin now Less blood is supplied to organs not important to exercise such as the liver and the GI tract Blood ow to the brain and the heart itself will not change though if anything it will increase These vital organs will need the greater supply of blood to function So as the body transitions to exercise blood is redistributed to the working muscles During exercise the total blood volume will also increase so not only is a greater percentage of the whole going to the muscle around 80 there is also a much greater volume of blood circulating the body The percentage to the brain and heart may decrease but since the total volume increased the amount of blood will be the same of greater 0 This can be interpreted from chart the events that cause this are vasodilation to the arteries going to the muscles Vasodilationgreater blood ow As arteries to muscles dilate the arteries to other organs constrict lowering blood ow The capillaries also have their own autoregulatory method to increase blood ow to muscles sphincters will relax in response to certain byproducts of metabolism Hions heat and C02 Vasodilation and Vasoconstriction are controlled by neurotransmitters ACH and NEEPI and their release 5 ultimately controlled by the brain 0 Physiologically the events that cause this are a vasodilation to the arteries going to the muscles Vasodilationgreater blood ow As the arteries to the muscles vasodilate the arteries to the liver and GI tract will vasoconstrict lowering blood ow The capillaries also have their own autoregulatory method to increase blood ow to the muscles the sphincters will relax in response to certain byproducts of metabolism such as H ions heat and C02 The vasodilation and vasoconstriction are controlled by the neurotransmitters Ach and norepinephrine and their release is ultimately controlled via the brain o If all vessels are dilated at one time then there is enough vascular surface area to contain 20qts of blood So if they are open at one time then venous return is lower and causes fainting Body will prioritize the ow of blood to where it is needed most 0 At rest working muscles get only 15 of cardiac output while the organs get 80 of cardiac output This switches during exercise 0 Blood Flow to Heart Increases during exercise Not only through but also to the heart remember myocardium is a muscle 0 Blood Flow to Lungs More blood through the lungs and to the respiratory muscle as well 0 To Brain By volume it will increase due to cardiac output but percentage wise it stays the same 0 To Skin The body strives to maintain internal core temp for organs Initially it drops but then it increases past resting levels in order to dissipate hear and maintain the core temp This change usually happens within minutes Hypothalamus is the thermostat In the event of dehydration the blood ow to the skin would reduce in order to eliminate excess water loss through the skin Blood ow to the skin greatly increase during lightmoderate exercise but during maximal exercise blood is shunted to active muscle 0 Visceral Organs During exercise blood is reduced to these organs to make available roughly 600mL of blood for skeletal muscle 13 What is venous return What factors in uence venous return 0 This is the amount of blood that is being returned to the heart via the veins and since the circulatory system is a closed loop meaning the amount of blood that leaves the ventricles will always equal the amount of blood that enters the right atrium so more blood returning means more blood pumped out Venous return is actually what contributes the greatest factor in increasing blood volume and Q by increasing EDV end diastolic volume thereby increasing SV This is in uenced by the muscle pump which is when the veins recoil during contraction which means every time the muscles contract blood is propelled back to the heart Another factor is the respiratory pump meaning every time our lungs in ate blood is propelled through the veins Then we have the oneway valve anatomy of the veins blood cannot ow backwards only forwards With high resistance pressure in the arteries following systole doesn t rapidly dissipate but remains elevated for a longer portion of the cardiac cycle 14 Describe the immediate acute adjustments made by the heart and circulatory system to allow for physical activity Give neural and hormonal mechanisms Give changes from rest to submaximal to heavymaximal exercise With each heartbeat ventricles pump out a certain volume of blood called the SV Since the left ventricle supplies blood to system circulation whole body this is the one to note When exercise starts the ventricle immediately stretches to accommodate the increase in blood ow The amount of blood entering the left ventricle is the EDV End Diastolic Volume The ventricle stretches and holds more blood with stretch also comes tension More stretchmore forceful contractions Just like a rubber band the more it stretches the more force is generated during contraction During exercise the chamber increases in size and thus contracts stronger meaning more blood is propelled out increasing SV This is the FrankStarling Mechanism The heart also increases contraction strength inotropically via calcium This is independent of the Starling Mechanism An increase in calcium in the heart will increase strength of contraction lnotropic means affecting heart rate directly Obviously HR increases as exercise starts but not as much as SV SV increases until roughly 40 of ones V02max Starling mechanism is responsible until then This is because the ventricle can only stretch so much After SV maxes out HR then increases considerably until max is reached 0 Mechanisms For an increase in HR is a withdrawal of vagal tone parasympathetic in uence until a HR of lOObpm the sympathetic system will kick in and increase HR This is with the neurotransmitter EpinephrineNE HR will slow with ACH i Contractile Strength will increase with an increase in calcium The Starling Mechanism is due to a greater venous return which increases EDV stretching the ventricles leading to more forceful contractions due to the greater length of the sarcomeres more actin and myosin binding Since more actin and myosin binding requires more calcium separating the Starling Mechanism and the intropic effect of contractility from calcium is fuzzy Weight lifting increases SBP Resistance increases DBP or stays the same 0 Always the best answer l stays the same DBP doesn t change as much as systolic 15 De ne cardiac output Explain How is cardiac output measured Fick method 0 Cardiac output expresses the amount of blood pumped by the heart during a 1minute period The maximal value re ects the functional capacity of the cardiovascular system Output depends on the rate of pumping HR and the quantity of blood ejected with each stroke SV QHRXSV Three methods to measure cardiac output of a closed circulatory system in humans 1 Direct Fick 2 indicator dilution 3 C02 rebreathing 0 Direct Fick Method 0 Two factors determine the output of uid from a pump in a closed circuit Change in concentration of a substance between the out ow and in ow ports of the pump Total quantity of that substance taken up or given off by the uid in a given time o For cardiovascular dynamics calculating Q requires knowledge of two variables 1 average difference between oxygen content of arterial and mixed venous blood aV02 difference and 2 oxygen consumption during 1minute V02The question is then how much blood circulates during the minute to account for the observed oxygen consumption given the observed aV02 difference V02 Q x aV02 difference V02max Qmaxx a V02 differencemax 0 Measuring oxygen consumption involves open circuit spirometry Measuring aV02 difference is a little more dif cult requiring a sample of arterial blood from any systemic artery femoral radial brachial This has high risks and only provides a sample for the area that it drains Therefore an accurate estimate of all venous blood has to be taken from a mixing chamber for an accurate read such as the right atrium right ventricle or pulmonary artery Arterial and mixed venous blood are then sampled simultaneously with measurement of oxygen consumption The invasive nature of the Fick method can alter normal cardiovascular dynamics during the measurement period that may not re ect the persons usual cardiovascular response 16 Give the mechanisms controlling stimulation in the heart rate prior to and during activity HR is controlled by the vagus nerve at rest This is the main parasympathetic input to the heart This nerve will slow down heart rate via the neurotransmitter ACH Then once exercise starts vagal tone to starts to decrease the heart increasing HR to lOObpm The sympathetic input takes over to increase it more with EPINE Then sympathetic input takes over to increase it more via epinephrine o The SA node sends an AP by itself every 60100bpm so the vagus nerve slows that down even more which is why it is possible to have a heart rate of 4050bpm So the rst vagal tone has to decrease which will bring the HR to lOObpm then sympathetic takes over So rst the vagal tone has to decrease which will bring the heart rate to 100 BPM THEN sympathetic will take over NE and EPI binds to beta 1 l respiration bronchial dilation via beat 2 0 Once exercise ceases sympathetic input will decrease and this will decrease HR Extrinsic Controls Accelerate the heart in anticipation before exercise begins then rapidly adjust to intensity of physical effort changes made by nerves that directly supply myocardium and chemical messengers NT hormones that circulate in the blood Intrinsic Controls heart maintains its own rhythm spontaneous activity Muscle nerves of heart can be excited 17 Describe the effects of parasympathetic and sympathetic nerves on cardiac function Sympathetic Cardio Accelerator Nerves arise from the spinal column They innervate the entirety of the heart but mainly around the SA and some around the AV HR Excitability Rate of Conduction Force of contraction will all increase The SNS releases catecholamine s EPI and NE EPI lasts longer but is not as strong as NE The two major in uences of EPI and NE 0 Chronotropic Effect makes the heart best faster 0 lnotropic Effect makes the heart neat harder meaning it increases contractility Parasympathetic comes from the vagus nerve Both innervate the heart From the medulla to the vagus nerve lnnervates entirety of the heart mainly the AV and SA nodes Antagonistic to SNS bers HR Rate of Impulse and Rate of Conduction through AV DECRASE PNS releases ACH PNS response is mediated by the cranial nerve vagus The PNS effectively slows heart rate by decreasing the rate of discharge from the SA Node Summary Parasympathetic decreases HR and contractility of the heart So the parasympathetic via the vagus nerve relaxes the heart The sympathetic will increase the HR and contractility so the heart pumps more forcibly 18 Explain the indirect method of measuring blood pressure What is systolic diastolic pressure What changes occur during exercise Explain peripheral resistance and factors which modify resistance to blood ow in exercise Auscultation Method This is with a cuff and stethoscope The cuff is place on your brachial artery and this is in ated to a suf cient pressure to occlude the artery and cut of the blood ow Then the pressure is slowly released and this as it starts to ow through the vessel you can hear the blood as it pounds on the wall with a stethoscope The rst sound you hear is the systolic and the last is the diastolic o SBP is the pressure of the blood on the arteries when the heart contracts systole So it is when the heart contracts 0 DBP is the lowest pressure of the blood on the arteries when the heart is resting in diastole During exercise 0 Systolic blood pressure will increase since this value is the pressure of the blood during contraction So it makes sense that the pressure will be greater since the heart is contracting faster o Diastolic blood pressure will remain the same or slightly decrease The reason is because since the DBP is the pressure of the blood during diastole heart lling with blood there is no reason it should increase Peripheral resistance was explained above as the TPR This is controlled via the diameter of the vessels vasoconstriction and vasodilation The vessel diameter also plays a role but the biggest change is via the diameter During exercise all the arteries to your muscles will dilate to allow more blood to be shunted to them and all the arteries to less active organs will constrict to lower blood supply to them With higher resistance pressure in the arteries following systole doesn t rapidly dissipate but remains elevated for a longer portion of the cardiac cycle 0 Arterioles have smooth muscles that can open and close 0 Need more BF during exercise open the areas that don t need BF close 0 Capillary density increase 0 The direct of BF shunted to the arterioles The more RBCs the more oxygen Increase BF l opening to the capillaries 19 Describe the microcirculation blood ow through the capillary bed Explain av02 difference in exercise and rest Give 02 values This is how the capillaries control the blood ow to the muscles Capillaries branch into multiple beds and most of these beds are blocked by sphincters at rest Since they are blocked blood ow will be restricted at the muscles and thus less blood will go to the muscle Once we start exercising by products of exercise force the capillary sphincters to relax and open Once open much more blood can get to the muscle Some products are H ions from lactate C02 increased respiration from more breathing increased heat via muscle contraction This is known as the autoregulation of the capillary beds as it is not controlled through nerves This value was explained in question 11 This is the difference in the arterial oxygen content and the venous oxygen content A greater difference means that more oxygen diffused at the capillarieshappens with exercise AS intensity increases oxygen consumption increases Makes sense Some numbers to use are 5 ml 02 at rest up to 15 ml 02 at max exercise So as the intensity increases the body uses more of the oxygen in the arterial end 20 What is the CR center How and from where is it stimulated How and to what doesitrespond The CR is the master area in the brain stem mostly in the medulla oblongata This is where the cardiovascular system is ultimately controlled 0 During exercise the cardiovascular system has to regulate blood pressure and the increased blood ow to the muscles The massive increase in blood increases the blood pressure and the CR has to control the blood pressure of the body through the vasoconstriction and vasodilation of the blood vessels Ultimately the control of blood pressure wins and the brain decrease blood ow to the muscles This is the purpose of the CR center 0 It responds to neural and hormonal I don t know why he has humoral on the guide responses The neural is all that we went over with the effects of the parasympathetic and sympathetic nerves on the heart the increasing the contractile strength of the heart and speeding up the heart rate along with the changing of the diameter of the blood vessels and depressing the heart The hormonal is the effects caused by epinephrine on the blood vessels The CVC speeds up heart rate constricts blood vessels causes dilation of the vessels and slows heart rate This sends to signal to start causing these affects Vasodilators innervates only arterioles of skeletal muscle and cardiac muscles ACH from the vagus nerve 21 What are neurotransmitters How do they exert their in uence and on what organs These are the chemical messengers of the nervous system They are how the body communicates The main ones are epinephrine and acetylcholine The effects of these have been explained multiple times Epinephrine is the main NT of the sympathetic nerves so it will speed heart rate increase heart contractility and constrict the blood vessels everywhere but the beta receptors on the skeletal muscle in case he mentioned the type of receptor Acetylcholine exerts its effect through the vagus nerve to slow down heart Neurotransmitter variety of molecules within axon terminals released into synaptic cleft in response to nerve impulse that change a membranes potential of the postsynaptic neuron Packaged into synaptic vesicles clustered beneath the membrane in the axon terminal on the presynaptic side of a synapse They diffuse across the synaptic cleft binding to speci c receptors in the membrane on the polysynaptic side of the synapse Usually followed by an AP at the synapse Ach stimulates muscle contraction in the receptors which stimulates muscle contraction 22 What are humoral and neural stimuli Neural stimuli is the sympathetic and parasympathetic stimulation Hormonal stimuli is with EPINE and ACH Can override Endocrine system to maintain homeostasis Preganglionic sympathetic nerve ber stimulate adrenal medulla cells affecting CR Center Neural changes are more direct and happen in higher brain centers Humoral is responding to concentration of ions or molecules in the blood stream bile other body uids stimulate hormone release An example such as insulin This hormone responds to an increase in blood sugar The molecule is the sugar that affects insulin release from the pancreas Target cells uptake glucose Sugar levels drop in capillaries inhibiting insulin release Temp pH C02 etc Humoral stimuli send info back to CR to respond to an event mostly indirect with exception of temp 0 Temp changes can be picked up by warm blood owing through brain indirect and by receptors direct o In the case of the heart more calcium in the heart increases contractility myosinactin binding lnotropic effect independent of the Starling Mechanism Calcium concentrations increase with intensity I don t know if he made a mistake but the heart is controlled via neural and hormonal stimuli not humoral The rst two stimuli were explained already neural is the sympathetic and parasympathetic stimulation and the hormonal is with epinephrine and acetylcholine Humoral means something is responding to a concentration of ions or molecules in the blood stream An example is with insulin This hormone responds to an increase in blood sugar The molecule is the sugar that affects the insulin release 23 What is the partial pressure of gas and how does it in uence the diffusion of gas at the lungs and tissue Partial Pressure of a gas is the pressure of the solution that is that speci c gas The partial pressure does not depend on other gases present For example the partial pressure is the barometric pressure x the percentage of gas in the solution So since the percentage of oxygen in air is 20 math gives it as 160mmHg This is vital to breathing Everything involving oxygen involves diffusion So high partial pressure diffuses because of the low pressure in the lungs o Inhalation the partial pressure of oxygen we are inhaling is 160mmHg it will diffuse into alveoli sacs in lung for gas diffusion The pressure is roughly 105mmHg here Once in the lungs it diffuses into blood pulmonary vein going to the heart with oxygenated blood because of the lower partial pressure in the blood stream In arteries the partial pressure of oxygen is 100mmHg Once passing the capillaries the oxygen will diffuse out of the blood into organs since the partial pressure is lower in the capillary beds Then in veins the partial pressure is 40mmHg for oxygen 0 So if the partial pressure of oxygen was lower the diffusion will not be that great and breathing will be hard Gases move via diffusion Oxygen travels on hemoglobin Once oxygen binds it is called oxyhemoglobin 24 Explain the gas laws of Dalton Boyle and Henry Gas exchange by diffusion takes place across membranes from high concentration to low concentration Gases are diffusible can be compromised tension made of a mix of molecules spread apart have high KE and gas is in motion colliding with one another The more gas molecules means the pressure will be increased when enclosed in a space this is due to the molecules bouncing around Pressure exerted is dependent upon the collisions which is dependent upon the amount of molecules Daltons Law goes as follows Pb 760 mmHg Pb P02 PCOZ PNZ The PP of OZ moves from OZ C02 moves COZ etc With this said some gases move at different rates PP in the lungs must be greater than the PP in the blod of OZ OZ is lower in the tissue than the blood arriving to the tissue C02 in blood going to lungs must be higher than C02 in lungs so that it may diffuse For a xed amount of an ideal gas kept at a xed temperature pressure and volume are inversely proportional Or Boyle39s law is a gas law stating that the pressure and volume of a gas have an inverse relationship when temperature is held constant In chemistry Henry39s law states quotAt a constant temperature the amount of a given gas that dissolves in a given type and volume of liquid is directly proportional to the partial pressure of that gas in equilibrium with that liquidquot Boyles Law Emlubility I 120 Henry 5 Law 100 Pressure 00 0 Ch 0 4O 4O 45 50 Fania Pressure 2 i i i i i 0 15 20 25 30 35 Volume 25 What are the different respiratory volumes and capacities One s breathing capacity is explained using different terms and this is how respiratory disorders are diagnosed Tidal volume TV is the amount of air that one inhale with a normal breathe This is normally around 500ml The after a normal inhale as we all know we can forcibly inhale much more air This is called the inspiratory reserve volume IRV Think of it as reserved air This can be anywhere from 21003200 ml depending on the strength of your intercostal muscles Then just as we can forcibly inhale more air we can forcibly exhale more air This is the expiratory reserve volume ERV around 10001200 ml extra Even if we exhale as much air as possible we will always have air left in our lungs This prevents the lungs from collapsing as there needs to be air to keep them in ated This volume that is stuck in the lungs is called the residual volume RV around 1200 ml The inspiratory capacity is the capacity that one has to inspire air so it will include the normal volume you inhale from the TV So mathematically it s TVRV The functional residual capacity is the amount of air left in your lungs after a TV So we know we can forcibly exhale more air plus there s air always left in the lungs so it is the ERVRV Then the vital capacity VC is the total amount of EXCHANGLE air meaning the RV is not included Then Total lung capacity is the sum of all the lung volumes now including RV usually 6000ml A portion of air never reaches the alveoli and this is called the anatomical dead space Around 150ml must be subtracted from the 500ml TV meaning we only passively so no muscle is used to inspire more air than normal use 350ml of air 26 What effect does exercise have on the oxygen cost of breathing With exercise we breathe faster or ventilate faster Ventilation is just like cardiac output it increases with exercise intensity Ventilation or VE is equal to TV x f this is tidal volume multiplied by the frequency of breathing every minute What does this look like CO HR x SV TV is synonymous to SV as they both measure an amount of air or blood like each breathe or beat produces So with exercise just like with CO VE increases Frequency of breathing increases just like with HR TV like SV will increase up to around 5060 of one s v02 just like SV Then the frequency of breathing will increase substantially just like the HR will as the intensity increases The respiratory system is a lot like the cardiovascular system o If you begin to exercise are you using muscles for respiration Do those muscles work harder Do you use more muscles Do the muscles use energy 0 Your body uses thes muscles at work and you use more during exercise 0 They increase during training 0 Know the BF at rest vs at exercise 27 What are the expected training effects from aerobic exercise on V5 hemoglobin blood volume etc 0 With training VE doesn t really increase as you can t increase the frequency of breathing with exercise So unlike CO VE does not increase with training our lungs do not get bigger or better at breathing o Hemoglobin doesn t really increase with training either you are born with a max amount of hemoglobin Of course we can lose hemoglobin via diet but you can t increase beyond what men usually have and women usually have This is why we cannot carry more oxygen with being in better shape Women will always have less hemoglobin that men women are around 12 gdl and men are up to 16 gdl Every gram of hemoglobin can contain 134 mL 02 98 of 02 is transported by hemoglobin with the remainder diffused into the plasma of the blood This is way all factors equal training enzymes lactate threshold etc men will always be faster than women 0 Hemoglobin has Fe2 which oxygen has a high af nity for 0 Even though the amount of hemoglobin doesn t change the solution content can creating a hemo concentration 10 hemo concentration on a 15gdl blood would give 155gdl blood This would be an advantage because it increases 02 carrying capacity Normal adaption 510 hemo concentration increases the ration making exercise more ef cient 0 Blood volume is the thing that increases with training 0 Etc does not change with training 28 Understand the importance of the oxyhemoglobin dissociation curve at rest and exercise 0 This is a curve that shows how saturated hemoglobin is with oxygen at certain pressures It is a sigmoidal curve showing that at a pressure around 70mmHg that the hemoglobin is almost 100 saturated Since the pressure of oxygen in the arteries is 100mmHg as explained above this means that the hemoglobin is nearly 100 saturated here which is what we expect 0 On curve you can also see at 40mmHg the hemoglobin is still around 60 saturated and since the pressure in the veins is 40mmHg there is still a lot of oxygen on the hemoglobin How can we use more of that oxygen Once we start exercising our body needs more oxygen so this curve has to change Certain factors will shift this curve to the right thus facilitating hemoglobin to unload more oxygen The factors are a higher body temperature an increase in PC02 the pressure of carbon dioxide so you basically have more in your blood to cause an increased pressure a lower pH and an increase in a molecule called BPG This all are results from exercise or from an increased metabolism This is a positive effect since it causes the hemoglobin to release more of its oxygen This is called the Bohr Effect 29 What is the Bohr effect 0 States that hemoglobin39s oxygen E hr Eiffest curves binding affinity see Oxygen m39 hemoglobin dissociation curve is High CUE low pH D E inversely related both to acidity and to the concentration of carbon dioxide 0 Relationship between P02 and saturation 0 Loading of blood if you measure the PP of 02 in the alveolar sacks I 100 mmHg 0 Look at the blood going into the lungs passes through the 5 E quot5 a Nurmal CUE normal pH Hh it 02 saturatiun Luw CUE high pH M E Erng Lungs tissues alveeli l I I ll ll I I ll l I Eli all ll El 1l illl Oxygen pressurer mm Hg alveolar capillaries you will see the PP of 02 in that blood is less high l low 0 The blood that exits the lungs into the pulmonary veins back into the ventricles is going to be fully saturated and represents the left side of the heart or arterial blood 0 You have blood coming in at 100 mmHg V02 and it is easy to see how that gas can diffuse from the blood into the cell 0 Relationship between P02 and 02 carrying capacity 0 You can go to the PP of 02 at 100 mmHg to 80 mmHg and still not compromise someone s oxygen ow to the blood Would be important for places with different elevations o The steep portion at 40 mmHg you can see that it is about 7 saturated but then 50 02 capacity Not only fully saturated but partially saturated and no longer carries 20 mL but now it carries 15 mL which tells you have extracted 5 mL l indication of av02diff IMPORTANT You can see decreases in barometric pressure that in uence the PP of the gas 02 and you don t have dramatic losses in your ability to saturate or carry 02 0 Very subtle changes in PP at the cell in uence dramatic changes in what you can extract 30 What factors shift the oxyhemoglobin dissociation curve to the right 0 When the curve shifts to the right this causes the hemoglobin to unload more of its oxygen This is a good thing All the factors that shift the curve to the right are a cue to the body that it is exercising High body temp increase in C02 pressure lower pH and increase in BPG Only thing that shifts it left are high altitudes Exercise Increases temperature Increases H ions Increases C02 tension 0 Curve shifts to the right Bohr Effect PP of 02 remains the same in the cell at 40 mmHg no effect on the shift 0 Exercising heavily loading as much as we could if we were loading at rest and still carrying 20 mL l BUT because of the shift there are increase in enzymes to do that activity Again you have extracted more indication of av02diff Starts out w 20 goes up to 7 l extracted 13 mL 0 Important in regards to where you are on the planet different altitudes Know what shifts the curve 31 What is the role of 23 diphosphoglycerate 23DPG A threecarbon isomer of the glycolytic intermediate Li bisphosphoglyceric acid 13BPG Present in human red blood cells 0 It binds with greater af nity to deoxygenated hemoglobin than it does to oxygenated hemoglobin due to spatial changes 0 It interacts with deoxygenated hemoglobin beta subunits by decreasing their af nity for oxygen so it allosterically promotes the release of the remaining oxygen molecules bound to the hemoglobin Thus enhancing the ability of RBCs to release oxygen near tissues that need it most 23BPG is thus an allosteric effector 32 How can avOz difference be determined from the oxyhemoglobin dissociation curve What is the practical importance of this information o This is a simple calculation You draw a line from the original curve to the curve shifted to the right The difference of the volumes will be the av02 difference 0 Have to know how to come up with an actual number 0 Right side of the curve you need to estimate av02diff based on your knowledge of the curve 0 P02 of 30 and of 50 l CO 0000 O Venous 4O mmHG Arterial 100 mmHG This is critically important when you are exercising at altitude because your blood can still operate at different pressures With changes in P02 there are minimal changes in OHbg During exercise shifts down and to the right Cause by increased metabolic heat Ph increase C02 Opposite low body temp and everything else l shifts curve up and to the left Able to upload oxygen better when exercising more ef ciently With the lactate l lactic acid l H ions effect oxygens binding with Hgb At rest binding 4 02 to Hemoglobin During the same thing during exercise with the presence of other things C02 and H ions wit prevent the binding of 02 and Hgb so the release occurs faster With each decrease it goes 98756050 etc Things are just unloading to tissues and this occurs with the increase in exercise
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