I think most of us know the heart pumps the blood and the blood vessels are the tubes that the blood travels in. We take the process for granted – the heart just does its thing. However, as blood pressure goes up the heart has to work harder to push against the greater pressure.
So what can cause blood pressure to rise? Constriction or narrowing of the blood vessels will directly impact the pressure exerted against the blood vessel wall. If you force water through a narrow opening, the stream that comes out is more forceful than the stream from a wider hose. Plaque buildup in blood vessels causes a narrowing of the vessels, called atherosclerosis, while hardening or thickening of the actual vessel wall, called arteriosclerosis, both can lead to high blood pressure (1).
The biggest problem is the snowball effect caused by the initial change in the system. Hypertension is called the “silent killer” because a person can go years without being aware there is a problem. Symptoms may not appear until the issue reaches a critical stage. As the elasticity of the heart muscle is lost the pumping action is impeded. A strong cardiac muscle means better pumping action.
The strength of the contraction helps the heart pump all the blood out of the ventricles. If blood is left in the ventricle the heart muscle stretches or dilates and that is bad. Think of a balloon filled with water. The stretched ventricular muscle is no longer at optimal stretch and cannot pump all the blood out. As the heart muscle stretches more and more blood gets left in the ventricle and less oxygen gets to the body. This is much like a rubber band that loses its elasticity and no longer has the tension needed to push against an object to hold it in place. The heart muscle loses its contractility and cannot squeeze tight enough to push the blood up and out. In order for the blood to flow freely throughout the body the cardiac muscle must be resilient, elastic, and strong.
There are 2 parts to our vesicular tubing – the arteries and the veins
. Between these 2 are the arterioles which are very thin. The vesicular smooth muscles of the arteries are thickest and very strong close to the heart in order to take the pressure of the blood being pumped out of the heart’s ventricles. Further away from the heart the smooth muscles of the arterial blood vessels are much thinner but they still have to be able to pump the blood into the arterioles which feed into the thinnest vessels called capillaries. All cells are in close proximity to capillaries in order for the blood to bring nutrients to the cells and to remove waste products produced by metabolism. The kidneys help filter out waste products.
The kidneys depend on normal blood pressure to allow the filtering process to work (2). There is also a kidney hormone (and others) that helps the body regulate blood pressure. Once one step in the process goes wrong, the process of hypertension, like a snowball rolling down hill, feeds on itself causing the issue to worsen every day (2). Edema is the fluid buildup brought on by the heart’s inability to pump properly. There may also be a vascular problem. The veins are not muscular like the arteries. They depend upon our movements to bring the blood back up – against gravity – to the heart.
The veins have 1 way valves that work as muscles are pushed against the vessel walls.Gravity wants to keep the blood in the ankles.However, when you move the muscle squeezes the vessel and blood is forced upward. It only moves up to the next valve. The valve closes at the bottom and keeps the blood from falling down again.
It sits there until the muscle squeezes it again forcing it up to the next valve and so on (3). This is why long airplane rides are dangerous. Too much time sitting and not moving the blood.
There are more details to the story but even this short explanation lets you know how important it is to keep your BP in control and the necessity of exercise to keep the blood moving.
- James D. Douketis, MD December 2012 https://www.merckmanuals.com/home/heart-and-blood-vessel-disorders/venous-disorders/overview-of-the-venous-system