Introduction to the Cardiovascular System - part 8 pptx

... vasoconstriction ( - adrenoceptor mediated), and contributes to the release of renin by the kidneys through re- nal ␤ -adrenoceptors. Other mechanisms besides the barorecep- tor reflex and hormones ... 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-...

Ngày tải lên: 11/08/2014, 11:22

... 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

... 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 ... 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 ... barorecep- tor activity (e.g., carotid sinus and aortic arch receptors) tonically inhibits sympa- thetic outflow to the heart and blood ves- sels, and it tonically stimulates vagal...

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 ... and the post -to- precapillary resis- tance ratio is 0.20. After inducing heart failure, the mean arterial pressure falls to 80 mm Hg, and the venous pressure increas...

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

... 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 volume. Therefore, the net effect ... residual volume added to the incoming venous return causes the end-diastolic volume to increase. This increases preload and acti- vates the Frank-Starling mechanism to...

Ngày tải lên: 11/08/2014, 00:20