Introduction to the Cardiovascular System - part 3 pdf

... causes the end-diastolic pressure- volume curve to shift up and to the left, as shown in Figure 4-2 7. This shift will reduce the end-diastolic volume and increase the end-diastolic pressure at the ... of the ventricles. Ejection occurs because the total energy of the blood within the ventricle exceeds the to- tal energy of blood within the aorta. The total ene...

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... within the AV node, which might prolong the P-R inter- val. Therefore, taking the patient off the ␤-blocker might improve AV nodal conduction and thereby decrease the P-R interval to within the ... filament. Ch 03_ 04 1-0 58_Klabunde 4/21/04 10:57 AM Page 43 wave of the QRS). About 20 milliseconds later, the mean electrical vector points down- ward toward the apex (vecto...

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... gradient, to enter the cell. As the m-gates open, the h-gates begin to close; however, the m-gates open more rapidly than the h-gates close. The difference in the opening and closing rates of the two ... depolarization to thresh- old opens the m-gates (voltage activated), thereby opening the channel and enabling sodium to enter the cell. Shortly thereafter, as t...

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... reflex. Mechano- receptor Mechano- receptor Mechano- receptor Chemo- receptor Chemo- receptor Chemo- receptor 2 Chemo- receptor Chemo- receptor Nociceptor Nociceptor Various Proprio- ceptor Proprio- ceptor, Chemo- receptor Thermo- receptor Thermo- receptor Internal Carotids ... baroreceptors) enter the medulla at the nucleus trac- tus solitarius (NTS), which projects inhibitory interneuron...

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... the autoregulatory range). This is because of the strong capacity of these organs to autoregulate and their ability to escape sympathetic vaso- constrictor influences. The autoregulatory re- sponse ... ␤ 2 -adrenoceptors) or in- creases (via vascular ␣ 1 and ␣ 2 -adrenocep- tors) systemic vascular resistance, depend- ing upon the plasma concentration. • The renin-angiotensin-aldo...

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... muscle, the muscle cells adjacent to the capillary take up the oxygen for use by the mitochondria. Consequently, little oxygen dif- fuses all the way through one cell to reach an- other. Therefore, ... only 25 35 mm Hg, which cor- responds to a 30 % to 60% loss of oxygen con- tent of the blood. Therefore, substantial amounts of oxygen diffuse out of the blood be- fore...

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... required to switch over to anaerobic gly- colysis for the production of ATP. Acidosis stimulates peripheral and central chemore- ceptors, leading to increased sympathetic ac- tivity to the systemic ... stimulation (␤ 1 -adrenoceptor mediated) and peripheral vasoconstriction ( - adrenoceptor mediated), and contributes to the release of renin by the kidneys through re- nal...

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... PHYSIOLOGICAL ACTIONS OF ENDOTHELIN-1 Endothelin-1 (ET-1) is synthesized from an endothelin precursor (big ET-1 or pro-ET-1) and cleaved to ET-1 by endothelin convert- ing enzyme (ECE) found on the endothelial cell ... are the same in the pre- and post- stenotic segments). Therefore, KE is the same in the post- and pre-stenotic segments. There is, however, an additional loss of PE...

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... Supplemental 6 /3/ 04 6 :31 PM Page 11 afterload (particularly aortic diastolic pres- sure) enables the end-systolic volume to de- crease slightly, but not enough to overcome the decline in end-diastolic ... be- cause of the large stroke volume ejected into the aorta. As long as the ventricle is not in fail- ure, normal end-systolic volumes can be sus- tained; however, the end...

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