The spread of pressure pushes blood to the peripheral blood vessels

2021-05-29 01:04 PM

Maintaining vascular tone reduces thrust because the better the vessel adapts; the more blood is pushed forward due to the increase in pressure.

During systole, the heart ejects blood from the aorta, initially only the proximal aorta becomes dilated because the inertia of the blood prevents abrupt passage of blood all the way to the aorta. Peripheral. However, a rapid increase in proximal pressure will overcome this inertia and blood flow throughout the artery, as shown. This phenomenon is called the propagation of pressure pushing blood in the arteries. The speed of this propagation is 3-5cm/s in normal arteries and 7 to 10m/s in larger arteries and 15-35m/s in small arteries.

In general, the more tone-maintained the vessel, the smaller the propagation speed and this explains why the slower propagation in the aorta and the smaller the distal arteries, the faster the propagation. than. In the aorta, the rate of propulsion propagation is 15 or more times that of the blood flow because hemodynamic pressure is simply the displacement of the pressure stream including the total displacement of the blood. The body of the blood volume moves slowly forward.

The pressure to push blood decreases gradually in the small arteries, arterioles, and capillaries.

The figure depicts changes in the path of the ejection pressure as well as the ejection of blood to the peripheral vessels. Pay special attention to the 3 curves where the intensity of the pulse becomes progressively weaker in the smaller vessels, in the arterioles, especially in the capillaries. In fact, it is only when the aorta beats are maximal, or the arterioles can dilate well that the pulse in the capillaries can be monitored.

Figure. Diagram showing the movement of blood pushing pressure in the aortic lumen

Figure. Changes in blood pushing pressure according to blood vessel size

The gradual decrease in peripheral pulsation is called the drop in blood pressure. The cause of this drop is due to two problems: the resistance of blood flow in the vessels and the maintenance of the tone of the blood vessels. Resistance reduces thrust because a small amount of blood needs to flow forward when there is a pulse to stretch the front segment. The greater the resistance, the harder it is for the blood to flow. Maintaining vascular tone reduces thrust because the better the vessel adapts; the more blood is pushed forward due to the increase in pressure. Thus, the magnitude of the reduction is almost a direct part of the resulting resistance times adaptability.