Mam phys lab 2 - Introduction: Ricke 2 The Cardiac cycle...

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Introduction:
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Ricke 2 The Cardiac cycle consists of a four chambered pumped composed of two upper portions called the left and right atria, and also two lower portions called the left and right ventricles. When the heart beats blood flows from the left atrium through the aorta to the rest of the body. Also, blood from the systemic venous blood is returned to the right atrium, and the pulmonary venous blood is returned to the left atrium (Johnson, 83). When referring to a cardiac cycle this is the period of time that extends from the end of one heart beat to the end of the next. This contains one period of contraction or known as systole and another period of relation or known as diastole. On an electrocardiogram this is shown as a one period of P-waves to the next P-wave the same as the cardiac cycle (Johnson, 83). Two heart sounds occur during one cardiac cycle. Blood pressure is one of the most important aspects to measure heart activity. When blood pressure measures near 0 this indicates diastole activity and when blood pressure is measured around 120mm Hg this is a state of systole. Valves are also an important tool in heart functioning. The atrioventricular valves prevent backflow of blood from the ventricle of blood from the ventricle to the atria, while permitting blood to flow through the aortic semilunar valve (Johnson, 83). Electrical activity of the heart is recorded by an ECG. These cardiac impulses or (CI’s) are recorded at the surface of the body, and are the results of the contractile events of the heart (Johnson, 90). The ECG produces a complex read as the QRS complex. The P wave precedes atrial systole, the QRS complex precedes ventricular systole, and the T-wave precedes the ventricular diastole. (Johnson, 90). The cardiac Impulse is what precedes the contraction of the heart, this usually begins within the SA node within the right atrium, and then moves to the AV node, where it is delayed, then it is passed on to the bundle of histamine. Finally, the CI is rapidly conducted through the Purkinje system. The ECG provides a great deal of information of
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Ricke 2 the electrical activity of the heart. Such as the location of the pacemaker (SA node), the path the impulse takes, and the rate of spontaneous depolarization. Also, the recordings of an ECG from electrodes placed in different positions on the surface of the body allows one to determine the average direction of current flow through the heart, indicating the anatomical orientation of the heart. (Johnson, 90) In the first experiment the goal is to hear the heart beat with the use of a stethoscope. This is important when checking for proper health, defects such as heart mummers can be detected by listening to the heart. If a person has a normal heart beat then a “lub-dup” sound should be heard through the stethoscope. In the second experiment atrial blood pressure is measured with a sphygmomanometer.
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Mam phys lab 2 - Introduction: Ricke 2 The Cardiac cycle...

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