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 bodyo Pumps blood to lungs for aeration through pulmonary circulation- Left sideo Receives oxygenated blood from lungso 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 contractions2. 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 Aorta3. What is the right side of heart responsible for?- Right sideo Receive blood returning from bodyo Pumps blood to lungs for aeration through pulmonary circulation4. 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 circulation5. 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 arterieso 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 arterioleso 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 cellso Some capillaries are so narrow that only one blood cell at a time can squeeze through- Capillaries feed deoxygenated blood into small veinso Veins in lower body eventually empty into inferior vena cava, while veins in upper body empty into superior vena cava6. Know size of above and the relationship of blood pressure (chart, numbers for stage 1 or 2) in each- Diameterso Arteries: 0.2-0.6 cmo Capillaries: 0.0005-0.001 cmo Veins: 0.5-1.1 cm- Blood pressureo Arterial blood pressure reflects the combined effects of arterialblood 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 capillaries7. 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 exerciseo Progressive expansion of a-vO2diff results from an increased cellular O2 extraction leading to a reduced venous O2 content8. Know cardiac output equation and its relationship to blood pressure- Blood pressure = Cardiac output × Total peripheral resistance (TPR)- Cardiac Output (Q)= MAP/ TPRo MAP= Mean Arterial Pressure= average force exerted by blood against arterial wall during cardiac cycleo TPR=Total Peripheral Resistance- MAP and cardiac output estimate change in total resistance to blood flow in the transition from rest to exercise9. 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 periodo Maximal values reflect the functional capacity of the cardiovascular system- Cardiac output = Heart rate × Stroke volumeo 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) 120o 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 #611. Factors that enhance venous return: muscle contraction, one way valves, pressure changes, and alternating of compression and relaxation of veins12. Know lifestyle changes chart that effects blood pressure13. Relationship of myocardium and oxygen extraction and how it has its own oxygen supply - At rest, myocardium extracts 70 to 80% of O2 from blood in the coronary vessels- 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 vesselso 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 anaerobic capacity- Extensive vascular perfusion supplies at least one capillary to each of the heart’s muscle fibers14. 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
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