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The beating of the human heart can be modeled by a thermodynamic cycle. In this chapter, we have used PV diagrams to show processes occurring for a gas. Such diagrams can also be used for a liquid, such as blood in the heart. The figure below shows an idealized cycle for the left ventricle (LV) during a single beat of the heart. P(mm Hg) D 120----- 78.0 20.0 10.0 A V (ml) 44.0 149 The cycle begins at point A with the opening of the mitral valve, which fills the LV with blood from the left atrium. During this process, the pressure and volume of the blood in the ventricle increase linearly until the mitral valve closes at point B. At that point, the muscles surrounding the LV contract, increasing the pressure of the blood. Because both the mitral and the aortic valves are closed, and because blood is essentially incompressible, the process is isovolumetric. The pressure increases to the diastolic pressure of 78.0 mm Hg (1 mm Hg = 133.322 Pa) at point C. Now, the aortic valve opens, pumping the contents of the LV into the aorta while the volume drops to that of point A and the pressure in the LV and aorta increase linearly to the systolic pressure of 120 mm Hg. Finally, the muscles surrounding the LV relax, decreasing the pressure of the blood remaining in the LV isovolumetrically to that of point A. (a) What is the work done (in J) by the blood entering the LV during the process A-B? (b) What is the net work done (in J) by the heart on the LV during one heartbeat?

The beating of the human heart can be modeled by a thermodynamic cycle. In this chapter, we have used PV diagrams to show processes occurring for a gas. Such diagrams can also be used for a liquid, such as blood in the heart. The figure below shows an idealized cycle for the left ventricle (LV) during a single beat of the heart. P(mm Hg) D 120----- 78.0 20.0 10.0 A V (ml) 44.0 149 The cycle begins at point A with the opening of the mitral valve, which fills the LV with blood from the left atrium. During this process, the pressure and volume of the blood in the ventricle increase linearly until the mitral valve closes at point B. At that point, the muscles surrounding the LV contract, increasing the pressure of the blood. Because both the mitral and the aortic valves are closed, and because blood is essentially incompressible, the process is isovolumetric. The pressure increases to the diastolic pressure of 78.0 mm Hg (1 mm Hg = 133.322 Pa) at point C. Now, the aortic valve opens, pumping the contents of the LV into the aorta while the volume drops to that of point A and the pressure in the LV and aorta increase linearly to the systolic pressure of 120 mm Hg. Finally, the muscles surrounding the LV relax, decreasing the pressure of the blood remaining in the LV isovolumetrically to that of point A. (a) What is the work done (in J) by the blood entering the LV during the process A-B? (b) What is the net work done (in J) by the heart on the LV during one heartbeat?

Elements Of Electromagnetics
Elements Of Electromagnetics
7th Edition
ISBN:9780190698614
Author:Sadiku, Matthew N. O.
Publisher:Sadiku, Matthew N. O.
ChapterMA: Math Assessment
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The beating of the human heart can be modeled by a thermodynamic cycle. In this chapter, we have used PV diagrams to show processes occurring for a gas. Such diagrams can also be used for a liquid, such as blood in the heart. The figure below shows an idealized cycle for the left ventricle (LV) during a single beat of the heart. P(mm Hg) 120 78.0 20.0 10.0 A V (mL) 44.0 149 The cycle begins at point A with the opening of the mitral valve, which fills the LV with blood from the left atrium. During this process, the pressure and volume of the blood in the ventricle increase linearly until the mitral valve closes at point B. At that point, the muscles surrounding the LV contract, increasing the pressure of the blood. Because both the mitral and the aortic valves are closed, and because blood is essentially incompressible, the process is isovolumetric. The pressure increases to the diastolic pressure of 78.0 mm Hg (1 mm Hg = 133.322 Pa) at point C. Now, the aortic valve opens, pumping the contents of the LV into the aorta while the volume drops to that of point A and the pressure in the LV and aorta increase linearly to the systolic pressure of 120 mm Hg. Finally, the muscles surrounding the LV relax, decreasing the pressure of the blood remaining in the LV isovolumetrically to that of point A. (a) What is the work done (in J) by the blood entering the LV during the process A-B? (b) What is the net work done (in J) by the heart on the LV during one heartbeat?
Transcribed Image Text:The beating of the human heart can be modeled by a thermodynamic cycle. In this chapter, we have used PV diagrams to show processes occurring for a gas. Such diagrams can also be used for a liquid, such as blood in the heart. The figure below shows an idealized cycle for the left ventricle (LV) during a single beat of the heart. P(mm Hg) 120 78.0 20.0 10.0 A V (mL) 44.0 149 The cycle begins at point A with the opening of the mitral valve, which fills the LV with blood from the left atrium. During this process, the pressure and volume of the blood in the ventricle increase linearly until the mitral valve closes at point B. At that point, the muscles surrounding the LV contract, increasing the pressure of the blood. Because both the mitral and the aortic valves are closed, and because blood is essentially incompressible, the process is isovolumetric. The pressure increases to the diastolic pressure of 78.0 mm Hg (1 mm Hg = 133.322 Pa) at point C. Now, the aortic valve opens, pumping the contents of the LV into the aorta while the volume drops to that of point A and the pressure in the LV and aorta increase linearly to the systolic pressure of 120 mm Hg. Finally, the muscles surrounding the LV relax, decreasing the pressure of the blood remaining in the LV isovolumetrically to that of point A. (a) What is the work done (in J) by the blood entering the LV during the process A-B? (b) What is the net work done (in J) by the heart on the LV during one heartbeat?
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