PHYS 1525 Cardiology, BP & Weight Control Notes

PHYS 1525 Cardiology, BP & Weight Control Notes -...

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Fundamental rules of the cardiac cycle 1. Electrical events precede mechanical events 2. The left and right sides of the heart do the same things at the same time (Pressures on the right side of the heart are lower than the left due to less resistance to blood flow in the pulmonary circuit than in the systemic circuit) 3. Blood flows from a region of high blood pressure to a region of low blood pressure 4. The A-V valves must be open for blood to flow from the Atria into the Ventricles. The Pulmonary and Aortic valves must be open for blood to flow out of the ventricles 5. Pressure rises in the heart chambers as blood flows into them 6. Pressure rises in the heart chambers when the cardiac muscle contracts 7. Pressure falls in the heart chambers as blood flows out of them 8. Heart sounds are caused by turbulent blood flow in the heart chambers or the aorta Normal heart sounds are the turbulent blood flow that occurs after the heart valves open or close. Heart murmurs or abnormal heart sounds are the result of stenotic valves that prevent normal blood flow, or insufficient valves that allow backwards flow of blood. Heart Sounds sounds of turbulent flow SI “LUBB” - beginning of systole AV valves (bicuspid and tricuspid) close, blood in the ventricles bounce off the walls of the ventricles and atria. S2 “Dubb” - end of systole Aortic and Pulmonary valves (semilunar valves) close. Blood bounces against the walls of the aortic and pulmonary valves. This is softer sound than S1 due to the aortic wall being smoother than the ventricular wall less turbulent flow. S3 - beginning of ventricular diastole Sound of blood flowing rapidly into the ventricles (soft sound often not heard) S4 atrial systole (end of ventricular diastole) Blood rushes into the ventricles due to atrial contraction. (soft sound often not heard) Heart murmurs: Extra "whooshes and clicks" due to abnormal flow of blood backwards due to insufficient valves. Mitral valve insufficiency: (AV valves between the left atrium and left ventricle) - most common form of heart murmur. Heard during ventricular systole. Increases the risk of developing infective endocarditus increases opportunity for bacteria to grow in heart. Can be congenital or caused by rheumatic fever autoimmune attack on the heart that often follows streptococcal infection "strep throat".
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Blood Pressure Study Notes Equations to know: Systemic Blood Pressure = Cardiac Output X Total Peripheral Resistance (TPR) Cardiac Output = Heart rate X Stroke Volume Systemic Blood Pressure = Heart rate X Stroke Volume X Total Peripheral Resistance Stroke Volume = End Diastolic Volume – End Systolic Volume End Diastolic Volume = End Systolic Volume + Venous Return Systemic Blood Pressure = Heart Rate X (EDV-ESV) X TPR Systemic Blood Pressure = Heart Rate X (ESV + Venous return) X TPR An increase in any of the above factors (except end systolic volume) will cause an increase in blood pressure if all other factors remain the same. Remember that vasodilation decreases
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PHYS 1525 Cardiology, BP & Weight Control Notes -...

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