Impulse of the artery

2021-05-31 05:03 PM

The pumping pressure at the aortic angle is shown in the figure. For a healthy young adult, the blood pressure at the beginning of each beat, called the systolic pressure, is about 120mmHg.

With each beat of the heart, a new wave of blood is pumped into the arteries. Without constriction of the arterial system, all this new blood would flow in the peripheral vessels almost instantaneously during systole, and during diastole, there would be no blood flow, however. , the adaptation of the arterial tree reduces the pulsating pressure of the heart to near non-pulsation by the time blood can reach the capillaries, so that blood flow to the tissues almost continues with a very small beat.

The pumping pressure at the aortic angle is shown in the figure. For a healthy young adult, the blood pressure at the beginning of each beat, called the systolic pressure, is about 120mmHg. At the lowest point of the pulse is called the diastolic pressure, about 80mmHg. The difference between these two values ​​of about 40 mmHg is called the pulse pressure (blood pressure difference).

Two main factors influence pulsating blood pressure: (1) the ejection volume of the heart and (2) the change in tone (ability to fully contract) of the arterial tree. Third, the less important factor is the ejection characteristics from the heart during systole.

Figure. Impulse curve of blood pressure in the ascending aorta.

 

Figure. Blood pressure in normal and pathological people

In general, the larger the ejection volume, the greater the amount of blood that must be contained in the arterial tree during each heartbeat and so the higher and lower the pressure during systole, which causes the arterial pressure to rise. blood increases. Conversely, the poorer the vascular tone, the greater the pressure for one stroke of blood to be ejected from the artery. For example, in a case demonstrated in the high midline curve, the blood pressure in the elderly is sometimes increased to 2 times normal because the arteries become stiffer due to the hardening of the arteries. and so will lead to hypotonicity.

Consequently, the ejection pressure is roughly determined by the ratio of ejection volume to the adaptive capacity of the arterial tree. Under conditions of the circulatory system, either factor can also affect Affects blood pressure:

Blood ejection pressure = (ejection volume)/(maintenance of arterial tone)