Introduction to the Cardiovascular System - part 9 ppsx

... 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...

Ngày tải lên: 11/08/2014, 00:20

... 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 ... University Press, 199 6. Wei JY. Age and the cardiovascular system. N Engl J Med 199 2;327:1735–17 39. 214 CHAPTER 9 Ch 09_ 18 5-2 14_Klabunde 4/21/04 11:47 AM Pa...

Ngày tải lên: 11/08/2014, 11:22

... 12 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 volume. Therefore, the net effect ... vein into the right atrium, passed into the right ventricle, then positioned within a branch of the pulmonary artery. There is one opening (port) at the tip of the cath...

Ngày tải lên: 11/08/2014, 11:22

... 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...

Ngày tải lên: 11/08/2014, 00:20

... 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 ... binds to b 1 -adrenoceptors, although it also can bind to ␣ 1 -adrenoceptors. Sympathetic nerve stimulation releases norepinephrine, which binds to ␤ 1 -adreno- ceptors and ␣ 1...

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... 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 ... occurs because the total energy of the blood within the ventricle exceeds the to- tal energy of blood within the aorta. The total energy of the blood is the su...

Ngày tải lên: 11/08/2014, 00:20

... 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...

Ngày tải lên: 11/08/2014, 00:20

... 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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... through the capillary loops and the venous plexus. In addi- tion to sympathetic neural control, the resis- tance vessels and AV anastomoses are very sensitive to ␣-adrenoceptor-mediated vaso- constriction ... 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 ce...

Ngày tải lên: 11/08/2014, 00:20

... 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...

Ngày tải lên: 11/08/2014, 00:20