Effect of peripheral resistance on arterial pressure

[coolia]

Hi, I know that arterial pressure increases as peripheral resistance increases. This is because blood begins to back up from the point of increased resistance and a greater volume causes greater pressure in the arteries. Also, the more stiff or rigid the artery the greater the pressure change will be. However, how come in many circuits by increasing resistance the voltage (analog of pressure) does not change but rather the current (analog of flow rate) changes. I know voltage does not change because it is a function of the battery. However why and how does current change?, why the difference between the two systems? Thank you.

I didn't know whether to put this in the physics or biology forum.

 

[Moonbear]

In the cardiovascular system, there is an increased pressure leading up to the site of occlusion, but through the narrowed section of arteries, there is also an increased flow rate. Blood vessels, however, are not rigid, except in areas of occlusion. So, as pressure increases, so does the vessel volume, and eventually, the ventricle of the heart (left ventricle if the problem is in most of the body, right ventricle if the increased resistance is due to pulmonary obstruction). This begins to gradually work backward through the entire cardiovascular system. When the organs reach a point where they can no longer expand to accommodate the pressure increases, in the case of blood vessels, they may rupture (i.e., ruptured aneurysms), or in the case of the heart, it simply ceases to have the strength to continue beating. In either case, you die when it reaches that point (without immediate medical intervention).

 

[oswaler]

I would approach this question from a physiological perspective. In the human body, the cardiovascular system is responsible for maintaining blood flow and blood pressure. The heart pumps blood through the arteries, which then branches off into smaller arterioles and eventually capillaries. The resistance in the arterioles is a key factor in regulating arterial pressure.

When peripheral resistance increases, it creates more resistance for the blood flow to overcome. This results in an increase in pressure within the arteries. This can be compared to squeezing a hose - the more you squeeze, the harder the water has to push through and the higher the pressure will be at the end of the hose.

The reason why increasing resistance does not always result in a change in voltage, or pressure, is because the body has mechanisms in place to regulate blood flow and maintain a constant pressure. For example, the heart can increase its pumping strength and rate to compensate for increased resistance and maintain the same pressure. Additionally, the body can also dilate or constrict blood vessels to adjust the resistance and maintain a constant pressure.

In terms of the difference between voltage and current in the cardiovascular system, it is important to remember that blood flow is not a simple electrical circuit. The body is a complex system with many factors at play, including hormonal and neural control. Therefore, while there may be some similarities to electrical circuits, it is not a direct comparison.

In conclusion, the effect of peripheral resistance on arterial pressure is a complex interplay between the heart, blood vessels, and regulatory mechanisms. While resistance does play a role in determining pressure, the body has mechanisms in place to maintain a constant pressure despite changes in resistance.