Arteries and Veins

Arteries and Veins

As we stated on the previous page, "What Is High Blood Pressure," arteries and veins are both part of the circulatory system and carry blood from the heart to the lungs and to all other parts of our bodies. Both are very important in maintaining our blood pressure.

Though they both carry blood through our bodies they are very different and are even made of different tissue and perform their own functions in specific ways.


Arteries. Arteries carry blood which is full of oxygen away from the heart.

Arteries have three layers of tissue - the outside and inside layers are made of a connective tissue which covers the muscular middle layer of smooth muscle, and elastic fibers. These tissues provide a smooth path for our blood to flow through.

Arteries contract and continue moving the blood along with a pumping action. Over time these cells can become damaged and can cause us problems. We will discuss some of these problems below.


Veins carry blood back to the heart from all of the outlying areas in the body after the oxygen has been delivered. Hence, it has very little oxygen in it and is usually filled with carbon dioxide. It is sometimes called "blue blood" but is actually very dark red.

Veins have thin walls and don't need to be as strong as arteries. They are very flexible and collapse when they don't have blood in them. Veins do not contract so therefore have valves which keep the blood moving forward and prevent it from going back and pooling in the extremities.

If the efficiency of the veins decrease some blood may stagnate in the vein, which then becomes swollen and twisted, causing aching and abnormal fatigue of the legs. This is a varicose vein.

The primary pump for moving blood in the veins and lymphatic system back to the heart is muscle contraction and other body movements. That is one reason why daily exercise is so important.

Doctors use veins as a portal in which to put fluids directly into the blood stream or from which to draw blood.

Isn't it interesting the way arteries and veins which are practically connected can be so different? 

How Do Arteries Work?

The American Heart Association has an excellent article on High Blood Pressure which talks about arteries and veins.

They explain that "healthy arteries are made of muscle and a semi-flexible tissue that stretches like elastic when the heart pumps blood through them. The more forcefully that blood pumps, the more the arteries stretch to allow blood to easily flow. Over time, if the force of the blood flow is often high, the tissue that makes up the walls of arteries gets stretched beyond its healthy limit. This creates problems in several ways."

  1. "Vascular Weaknesses.

            The overstretching creates weak places in the vessels, making them more prone to rupture.  Problems such as strokes and aneurysms are caused by ruptures in the blood vessels. 

       2.  "Vascular scarring.

           The overstretching can cause tiny tears in the blood vessels that leave scar tissue on the walls of the arteries and veins.  These tears and the scar tissue are like nets, and can catch debris such as cholesterol, plaque or blood cells traveling in the bloodstream."  (American Heart Association, "What is high blood pressure?)

What Are Cause of the Arteries Narrowing?

  • Stress. When we are under stress our bodies release a hormone called adrenaline. This is the hormone that makes it possible for people to rip the doors off of cars in order to pull someone from a burning car. So it is good. But it can also be bad.  
  • This stress causes certain blood vessels to constrict which raises our blood pressure. We know we are going to have elevated blood pressure if we just ripped off a car door - or if we just got chased by a bear - or if our boss just deflated us, or if any of a million things happened that caused us sudden stress.
  • Now, if we are under a lot of stress a lot of the time it means that our arteries and veins are constricted a lot of the time and that our heart is working way too hard a lot of the time.
  • Blood Clots. Blood clots form when blood coagulates and goes from a liquid state to a solid state. When a blood clot happens inside of arteries and veins or in the heart it is known as a thrombus, or an embolus when it travels to a different part of the body.
  • Blood clots can get trapped in the arteries because of vascular scarring and can block the arteries.
  • Even worst than being trapped, they can break off and block some other spot in the arteries which stops the flow of the blood carrying oxygen.
  • This is what causes strokes and often heart attacks as well.
  • Cholesterol. The blood vessels also become constricted when we have a cholesterol or plaque build up. Just as with blood clots, cutting off the supply of blood caused pressure to build up forcing the heart to work harder.
  • You can also have pieces of plaque break off and travel to other parts of the body blocking the vessel. And once again heart attacks and strokes can occur.
  • Age. As we age our arteries and veins can lose their elasticity which causes them to collapse blocking the flow of blood, and once again our heart has to work too hard to push the blood through, or allowing blockages by blood clots or cholesterol.
  • Tobacco. The death rate from heart disease is 300% higher in smokers than in non-smokers in North America. What more needs to be said?

What If Our Heart Works Too Hard?

When our hearts work too hard because of problems in the arteries and veins it can cause heart failure in the form of:

  • Heart attack
  • Heart disease
  • Congestive heart failure
  • Aortic dissection and
  • Atherosclerosis (fatty buildups in the arteries that cause them to harden)
  • Stroke
  • Kidney Failure.  It can also cause kidney failure. This sounds odd, but The American Heart Association explains it this way:"High blood pressure causes artery damage, and the kidneys are packed with arteries. Kidneys are supplied with dense blood vessels, and high volumes of blood flow through them. Over time, uncontrolled high blood pressure can cause arteries around the kidneys to narrow, weaken or harden.
  • "These damaged arteries are not able to deliver enough blood to the kidney tissue.  Damaged kidney arteries do not filter blood well.
  • "Kidneys have small, finger-like nephrons that filter your blood. Each nephron receives its blood supply through tiny hair-like capillaries, which are the smallest of all blood vessels. When the arteries become damaged, the nephrons do not receive the essential oxygen and nutrients.
  • "Also, the kidneys lose their ability to filter blood and regulate the fluid, hormones, acids and salts in the body. Damaged kidneys fail to regulate blood pressure.
  • "Healthy kidneys produce a hormone to help the body regulate its own blood pressure.
  • Kidney damage and uncontrolled high blood pressure each contribute to a negative spiral. As more arteries become blocked and stop functioning, the kidneys eventually fail. This process can happen over several years, but it can be prevented."
  • Vison Loss.  High blood pressure can also cause Vision loss. The American Heart Association describes this also:High Blood Pressure can strain the vessels in the eyes and the optic nerve. High blood pressure can place a strain on the blood vessels in the eyes. It can cause the blood vessels to either narrow or bleed when they are subjected to too much blood pressure force.
  • "Also, the optic nerve may swell, reducing the ability to see well.  Untreated High Blood Pressure can cause permanent vision problems.
  • "Using an opthalmoscope, a healthcare professional can look at the network of tiny capillaries on the retina to evaluate the condition of the blood vessels in the eyes.
  • Managing blood pressure is the only way to treat hypertensive retinopathy. High blood pressure damage is cumulative, so the longer it goes untreated, the higher the likelihood of permanent damage."
  • Stroke.  High Blood Pressure can cause a stroke, which may lead to brain damage causing vision loss. High blood pressure can lead to stroke, which, in turn, can impair the optic nerve or damage the area of the brain responsible for processing images.
  • High blood pressure can also cause other problems as well which include:
  • Fluid loss.
  • Fluid in the lungs.
  • Angina.


Besides answering, what the difference in arteries and veins is, what causes the arteries to narrow, and what if our hearts work too hard, we also need to look at symptoms for a few minutes.

High Blood Pressure Symptoms.

There are usually no symptoms! The list above does not list symptoms, but rather the results of high blood pressure. Remember that high blood pressure is a symptomless disease. Often we do not know that we have it until we experience a heart attack, stroke, or other heart failure.

The only time we have symptoms is when our blood pressure has reached a critically high level - known as a hypertensive crisis. If our blood pressure gets this high we may possibly have a nose bleed, a headache, severe anxiety, or shortness of breath. If we have these symptoms we are in trouble. These are extremely critical symptoms.

How High Is Too High?

If we are having any of these symptoms or just feeling "wierd" we need to take our blood pressure immediately. If it is 180 systolic or higher and/or 110 diastolic or higher, (180/110) we need to immediately call 911 and get to the hospital. Don't wait a minute. Our life is in danger.

Even if for some reason we don't have a heart attack, our arteries and veins can suffer so much inflammation that they may leak, making it impossible for blood to be pumped to all of our critical body systems. This can result in major organ damage.

High Blood pressure is no joking matter. Take it seriously.

Is There Anything We Can Do?

Yes. Don't dispair. There are things we can do.

Read our page on Food for High Blood Pressure and

our page on High Blood Pressure Herbs.

And coming soon we will have a page on Exercise and High Blood Pressure.

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