Blood vessels – Types, Layers, and more 

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Blood vessels act like channels through which the blood is distributed throughout the body.  

Blood vessels transport blood to all tissues in the body. They help deliver oxygen, nutrients, and other essentials for the organs and also help remove waste products from the body.  

What are blood vessels?

Imagine a pipe-like structure that supplies water from a tank to your tap. Similarly, blood vessels are channels that transport oxygen via blood throughout the body.  

Surprisingly our body contains 96,560 km length of blood vessels. Nature never fails to amaze us. Not many of us would have imagined our body contains blood vessels that are so long.  

These long channels fit in the body as they form a closed circuit that begins and ends in the heart.  

In simpler words, if our body is a racetrack, then the heart is like the starting point of a racetrack. The blood vessels are like race cars. They move around the entire track and finish at the finish line – at heart.

What are the types of blood vessels?

Our body comprises three types of blood vessels. They are:

Arteries, veins, and capillaries

  • Veins carry blood to the heart
  • Arteries carry blood away from the heart.
  • Capillaries are tiny blood vessels connecting the arteries and veins.  

A magnified look at the blood vessels


Veins are blood vessels that carry blood to the heart. The blood enters the smallest veins called venules, and from the venules, it flows gradually to the larger veins until it reaches the heart.  

The blood in the veins carries more oxygen as it is freshly oxygenated in the lungs. The wall of veins has three layers and fewer muscles or connective tissues making the veins thinner and enabling them to hold more blood.  

Approximately 70% of the total blood volume in our body is in the veins.

Venous valves are present in the heart and keep the blood flowing and prevent the backflow of blood.  


The arteries are major blood vessels that carry blood from the heart to other parts of the body. Pulmonary arteries transport blood that has minimal oxygen from the right ventricle to the lungs for oxygenation.  

Systemic arteries transport the oxygenated blood from the left ventricle to the tissues. Blood is pumped from the ventricles to the arteries and moves into smaller arteries until the blood reaches the microscopic artery known as arterioles.

These arterioles play a significant role in regulating the blood flow in and out of the tissue capillaries.  

Approximately 10% of the total blood volume in the body is found in the symmetrical arterial system.   


The capillaries are the smallest and the most present blood vessels, meaning they are more in number. This forms a connection between the blood vessels carrying blood away from the heart and the blood vessels carrying blood to the heart.  

The primary function of capillaries is to exchange nutrients and other materials between blood and tissues.  

How does the blood flow through the body?

  • The veins in the body carry blood to the right side of the heart.  
  • The pulmonary arteries will carry the blood to the lungs, where it gets oxygenised.  
  • The pulmonary veins will transport the blood, which is rich in oxygen, to the left side of the heart.
  • The main artery in the body, called the aorta, carries the blood from the left side of the heart to various body parts with the help of arteries.
  • Capillaries having thin walls allow the oxygen, nutrients, and other waste products to pass to and fro from the tissues to the blood.  
  • The veins circulate the blood back to the heart, and the cycle repeats.  

What is the purpose of blood vessels in the body?

The primary objective of the blood vessels in the body is to transport blood to the organs.  

The blood carries oxygen and other nutrients to the organs to function smoothly. These are also responsible for carrying carbon dioxide and waste from the tissues.  

Every blood vessel serves a different function. Their functions are as follows:


Arteries are strong, muscular blood vessels carrying precious oxygen-rich blood from the heart to various parts of the body.  

This blood vessel handles a large amount of pressure from the blood flow but does not carry more volume of blood. Approximately 10 or 15% of the total body is in the arteries.  


The arteries subdivide into smaller is known as arterioles. The arterioles are flexible, just like the arteries. They vary in size to maintain the body’s blood pressure.


The capillaries have thin walls and are small in size. The essential nutrients and oxygen from the blood will move into the tissues through the walls.  

Capillaries are where the oxygen and other nutrients are exchanged for waste carried away from the tissues.  


The veins in the body begin as tiny blood vessels called venules. These venules get larger as they move closer to the heart. Blood is passed to the venules through the capillaries.  


Veins carry a large volume of blood throughout the body. The walls of the veins are helping themselves to handle a high volume of blood and low pressure.  

The valves present in the veins keep the blood flowing in one direction. At any point in time, approximately 75% of the total blood volume is present in the veins.  

What are the layers of blood vessels?

Blood vessels possess three layers of tissues, namely:

  • Tunica intima
  • Media
  • Adventitia

Keeping the blood vessels healthy is essential to prevent the development of various health conditions or disorders.  

Various factors like genetics, heart disease, injury, infection, or medication can cause trouble. Some of the problems that can affect the blood vessels are as follows.  


An aneurysm is a bulge that occurs in a week or damaged part of an artery. This can occur anywhere in the body, and if they break open can be life-threatening. The rupture causes internal bleeding and requires immediate medical attention.  

Arterial diseases

Arterial diseases include coronary heart disease, peripheral artery disease, and carotid artery disease. These diseases smooth the flow of blood throughout the body.  


Atherosclerosis Is the builder of cholesterol or other substances in the arteries. This buildup is commonly known as plaque.

If there is plaque buildup in the arteries, it may eventually lead to a heart attack or stroke.  

Blood clots

A blood clot is a blood clump that accumulates inside the veins or arteries. The blood clot can lead to various health conditions and even be life-threatening.

High blood pressure  

High blood pressure or hypertension can occur when too much force or pressure is exerted on the arteries’ walls.  

Having high blood pressure is risky and adversely affects the health of a person.  

Raynaud’s disease

This health condition causes arteries to supply blood to the skin and get very narrow due to cold temperatures.  

Varicose vein

Varicose veins are enlarged or twisted veins that usually occur in the legs or feet. Any vein close to the skin is at a higher risk of getting varicose.   

Usually, this occurs due to pressure exerted in the veins of the lower body while standing or walking.


Vasculitis is inflammation of blood vessels. The walls of the blood vessels get inflamed and thick, preventing the smooth flow of blood through the body.

What are the causes of vascular diseases?

Some of the causes of diseases are not known. However, some of the factors that can cause diseases are as follows.

  • Excess cholesterol  
  • High blood pressure  
  • Smoking  
  • Genetic factors  
  • Medications  
  • Injury  
  • Infections  
  • Blood clots and  
  • Diabetes

What does the body exhibit when it has vascular diseases?

Symptoms of blood vessel disorder where is based on the health condition. Some vascular diseases will not cause any symptoms until they become severe problems.  

Some of the symptoms are as follows

  • The skin colour changes to a slightly bluish tone.  
  • Difficulty in performing activities
  • Tiredness and fatigue  
  • Pain in various parts of the body like the chest, arms, or legs
  • Breathlessness

It is crucial to address these symptoms immediately under proper medical supervision.  

How is the problem with a blood vessel diagnosed? 

A doctor or a healthcare provider will use various tests the diagnosis health conditions relating to a blood vessel. Some of them include ultrasound, electrocardiography, echocardiography, CT scan, MRI, exercise stress test and cardiac catheterisation.

How do health care providers treat blood vessel disorders?

Treatment for blood vessel disorders includes the following.

Making lifestyle changes  

There are chances of reducing the risk of developing disorders by quitting smoking, limiting alcohol consumption and maintaining a healthy body weight.  

Also, restricting food that can cause harm to the body is essential to maintaining good overall health.


Surgery is an option for certain blood vessel condition that is not responsive to medication.  

During surgery, a doctor will make an incision in the skin to access the blood vessels and treat the condition.  


When the disorders are set in and exhibit symptoms, health care providers can prescribe some medication to manage the BP and reduce the risk of developing blood clots of a person.

Such medications can also lower cholesterol levels in the body.  

Non-surgical procedure

A doctor can also recommend nonsurgical procedures for a few blood vessel disorders.  

These procedures use thin, flexible tubes inserted into the body and blood to treat blood clots and other smaller blood vessel problems.  

When there is a need for medical intervention?

Medical attention is mandatory if a person exhibits any of the following symptoms that can be a symptom of a health complication.  

  • Confusion  
  • Difficulty in speech  
  • Numbness  
  • Vision loss  
  • Fatigue  
  • Fast heartbeat
  • Pain in the chest  
  • Breathlessness and  
  • Swelling

Regular health checkups can help a person identify various health conditions quickly before it develops into more complex condition.  

How to prevent blood vessel disorders?

Keeping the blood vessels healthy is the only way to prevent blood vessel disorders. The blood vessels can be in good health if

  • A person consumes a balanced meal low in sodium
  • Performs regular exercise
  • Maintains optimal blood pressure
  • Quit smoking
  • Limited alcohol consumption

Making these subtle lifestyle changes can make a big difference in improving the overall health of a person.  

To sum up

Blood vessels carry blood throughout the body and deliver them to the vital organs and tissues. They are also responsible for delivering oxygen and removing waste products from the body.  

Blood vessels include arteries, veins and capillaries. Blood vessels that are healthy can prevent further health complications.  

If a person exhibits symptoms of unhealthy blood vessels, it is essential to consult a doctor for personalised advice.  


What is special about blood vessels?

The primary function of blood vessels is to deliver blood and other nutrients to the tissues and organs. These are also responsible for removing waste from the body.  

Explain the blood flow functioning of the blood vessel?

The pulmonary arteries are responsible for carrying the blood to the lungs, where the blood gets oxygenated.  
The pulmonary veins move the oxygenated blood to the left side of the heart.  
The aorta carries the blood from the left side of the heart to the rest of the body with the help of arteries.  

What increases the risk of blood vessel damage?

Vascular diseases can affect the blood vessels. Factors like plaque buildup, diabetes and high cholesterol damage the blood vessels. In some cases, genetic conditions can cause damage.  

What are some blood vessel diseases?

Some of the blood vessel diseases are as follows  
1·Abdominal aortic aneurysm
3·Carotid artery disease  
4·Peripheral vascular disease
5·Varicose veins


The Information including but not limited to text, graphics, images and other material contained on this blog are intended for education and awareness only. No material on this blog is intended to be a substitute for professional medical help including diagnosis or treatment. It is always advisable to consult medical professional before relying on the content. Neither the Author nor Star Health and Allied Insurance Co. Ltd accepts any responsibility for any potential risk to any visitor/reader.

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