1 Anatomy of heart Four chambered organ that pumps 70 ml of blood for each beat stroke volume Myocardium is heart muscle made up of myocardial fibers Right side o Receive blood returning from body o Pumps blood to lungs for aeration through pulmonary circulation Left side o Receives oxygenated blood from lungs o Pumps blood into thick walled muscular aorta for distribution via systemic circulation Two sides separated by interventricular septum Atrioventricular valves o Tricuspid provides one way blood flow from the right atrium to right ventricle o Bicuspid Mitral provides one way blood flow from left atrium to left ventricle Semilunar valves o Located in arterial wall just outside heart prevent blood from flowing back into the heart between contractions 2 Flow of blood Superior and Inferior Vena Cava Right atrium Tricuspid AV valve Right ventricle Pulmonary Valve Pulmonary Artery to lungs Pulmonary veins away from lungs Left Atrium Bicuspid Mitral Valve Left Ventricle Aortic Valve Aorta 3 What is the right side of heart responsible for Right side o Receive blood returning from body o Pumps blood to lungs for aeration through pulmonary circulation 4 Systemic vs pulmonary or myocardium circulation Heart functions as two separate pumps one pump receives blood from the body and pumps it to the lungs for aeration pulmonary circulation the other receives oxygenated blood from the lungs and pumps it throughout systemic circulation 5 Circulatory system know flow from arteries to arterioles to capillaries The heart has its own circulatory network the coronary circulation that arises from the heart s top portion Right and left coronary arteries o Greatest blood volume flows in left coronary artery to left atrium and left ventricle and right ventricle Blood pumped from left ventricle enters aorta and is distributed throughout the body through a network of arteries and arterioles o Smooth muscle in arteriole walls either constrict or relax to regulate blood flow to periphery Arterioles branch and form smaller and less muscular vessels called metarterioles Metarterioles end in microscopically small blood vessels called capillaries that contain 6 of total blood volume Capillary wall consists of a single layer of rolled up endothelial cells o Some capillaries are so narrow that only one blood cell at a time can squeeze through Capillaries feed deoxygenated blood into small veins o Veins in lower body eventually empty into inferior vena cava while veins in upper body empty into superior vena cava 6 Know size of above and the relationship of blood pressure chart numbers for stage 1 or 2 in each Diameters o Arteries 0 2 0 6 cm o Capillaries 0 0005 0 001 cm o Veins 0 5 1 1 cm Blood pressure o Arterial blood pressure reflects the combined effects of arterial blood flow per minute and resistance to flow in peripheral vasculature Systolic Blood Pressure SBP o Provides estimate of work of heart and force blood exerts against arterial walls during systole Diastolic Blood Pressure DBP relaxation phase of cardiac cycle diastole o Indicates peripheral resistance or ease that blood flows from arterioles into capillaries 7 Know normal numbers for oxygen exchange during rest and exercise During rest 15 mL of O2 75 of blood s original O2 content still remains bound to hemoglobin Arterial blood O2 content varies little from 20 mL dL at rest throughout the exercise intensity range Mixed venous O2 content varies between 12 to 15 mL dL during rest to 2 to 4 mL dL during maximal exercise o Progressive expansion of a vO2diff results from an increased cellular O2 extraction leading to a reduced venous O2 content 8 Know cardiac output equation and its relationship to blood pressure Blood pressure Cardiac output Total peripheral resistance TPR Cardiac Output Q MAP TPR o MAP Mean Arterial Pressure average force exerted by blood against arterial wall during cardiac cycle o TPR Total Peripheral Resistance MAP and cardiac output estimate change in total resistance to blood flow in the transition from rest to exercise 9 Vo2 as it related to cardiac output and avo2 difference the equation Cardiac output expresses the amount of blood pumped by the heart during a 1 min period o Maximal values reflect the functional capacity of the cardiovascular system Cardiac output Heart rate Stroke volume o Methods to assess cardiac output Direct Fick equation Indicator dilution CO2 rebreathing Fick Equation Expresses relationships between VO2 mL min and a vO2diff mL 100mL blood to determine cardiac output mL min o Cardiac output VO2 a vO2diff o Requires complex invasive methodology VO2 L min using open circuit spirometry average difference between O2 content of arterial and mixed venous blood a vO2diff 10 Blood pressure of systolic and diastolic and what they represent Systolic Blood Pressure SBP 120 o Provides estimate of work of heart and force blood exerts against arterial walls during systole Diastolic Blood Pressure DBP 80 relaxation phase of cardiac cycle diastole o Indicates peripheral resistance or ease that blood flows from arterioles into capillaries Also refer to chart on 6 11 Factors that enhance venous return muscle contraction one way valves pressure changes and alternating of compression and relaxation of veins 12 Know lifestyle changes chart that effects blood pressure 13 Relationship of myocardium and oxygen extraction and how it has its own oxygen supply coronary vessels At rest myocardium extracts 70 to 80 of O2 from blood in the Proportionate increase in coronary blood flow in exercise provides sole mechanism to increase myocardial O2 supply Two factors increase myocardial blood flow o Elevated myocardial metabolism dilates coronary vessels o Increased aortic pressure during exercise forces a proportionately greater volume of blood into coronary circulation Myocardium depends on adequate O2 supply because it has limited Extensive vascular perfusion supplies at least one capillary to each of anaerobic capacity the heart s muscle fibers 14 At rest oxygen is extracted at 78 15 Type of exercise prescribed for someone with high blood pressure what do they NOT prescribed It is recommended that someone with hypertension do 30 min a day of aerobic activity like brisk walking It is recommended that hypertension sufferers DO NOT do acute cardiovascular strain with heavy resistance exercise because it could prove harmful to individuals 16 Systolic and diastolic BP during exercise diastolic stays about the same during exercise
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