Introduction to the Cardiovascular System - part 6 docx

... 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 ... 6- 9 ; Table 6- 3 ). The transient in- crease in heart rate is due to norepinephrine binding to ␤ 1 -adrenoceptors in the sinoatrial node, whereas the secondary bradycardia...

Ngày tải lên: 11/08/2014, 00:20

... 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 ... heading di- rectly toward the positive electrode, gives the greatest positive deflection. As the vector moves around the axis to the left, and therefore moves away from th...

Ngày tải lên: 11/08/2014, 00:20

... 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 ... falls. The curve representing the frequency of barore- ceptor firing in Figure 6- 6 is the integrated re- cepto...

Ngày tải lên: 11/08/2014, 00:20

... 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 ... 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 the blood reac...

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

... 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

... 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 en...

Ngày tải lên: 11/08/2014, 00:20

... which is the system used in the United States—as compared to the parliamentary system, which is the British system, the system used in the U.K. Now, uh, under the presidential system, there is a ... of them. Please begin speaking after the beep. [20-second pause, then beep] [60 -second pause, then beep] Now stop speaking. Narrator: This is the end of the Speaking...

Ngày tải lên: 25/01/2014, 23:20