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The difference between arteries and veins is that the arteries carry oxygenated blood, while veins carry the deoxygenated blood to the heart (except the pulmonary arteries and veins). Arteries and Veins form the pathways of the circulatory system and are involved in the circulation of blood throughout the body.
There are three different layers of arteries and veins, which are:
- The innermost layer or Tunica Intima.
- The middle layer or Tunica Media.
- The outermost layer or Tunica Adventitia.
Arteries carry the oxygen-rich blood from the heart to the different organs and their respective cells for the production of energy. And, the veins carry the deoxygenated blood from those cells back to the heart.
Read Also: Blood Pressure
| Table of Content |
Key Terms: Artery, Vein, Muscles, Blood, Heart, Circulatory System, Oxygen, Carbon Dioxide, Cells
What are Arteries?
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Arteries are blood-carrying vessels that carry oxygenated blood from the heart (with every heart contraction) to other parts of the body.
- The largest artery in the body is the Aorta, attached to the left ventricle of the heart.
- An Exception is a pulmonary artery carrying deoxygenated blood from the heart to the lungs for enriching them with oxygen.
Characteristics of Arteries:
- Placed deep in the muscle
- Arteries have extremely thick walls
- Arteries carry blood from the heart to the organs
- Carries oxygenated blood (excluding the pulmonary artery)
- It has a thick layer of muscle tissue inside
- No valves (excluding the pulmonary artery)
Heart Diagram
Types of Arteries
The types of Arteries and their functions are as mentioned below:
| Type of Artery | Function |
|---|---|
| Elastic Arteries | The thick middle layer of these arteries is able to stretch in response to each heart pulse due to its numerous collagen and elastin filaments. |
| Muscular Arteries | They are made up of smooth muscles and are able to easily expand and contract based on the amount of blood and connect elastic arteries and arterioles. |
| Arterioles | They are minute-sized blood vessels branching from arteries and have thin walls. Oxygen and nutrients pass into tissues carried by the blood through these thin walls. |
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What are Veins?
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Veins are the blood-carrying vessels which carry deoxygenated blood from the heart (with every heart dilation) from other parts of the body to the heart.
- The largest veins are two in number named the superior vena cava and the inferior vena cava directly pours blood into the right atrium of the heart.
- The only exception is the pulmonary veins and unlike other veins, they carry blood which has been oxygenated in the lungs back to the heart. They are four in number and enter the heart through the left atrium.
Characteristics of Veins.
- Situated closer to the surface of your body
- Thin walls
- Carries blood towards the heart
- Carries deoxygenated blood
- Thin layer of muscle tissue
- Comprises valves to keep blood flowing
Types of Veins
The types of veins and their functions are listed below:
| Type of Vein | Function |
|---|---|
| Deep Veins | As the name suggests they are located at greater depths within the body, unlike the veins which can be seen underneath the skin. |
| Superficial Veins | These veins which are visible just beneath the skin that is they are not located in deep places are known as superficial veins. |
| Venules | They are the thinnest veins present in the body and collect deoxygenated blood from the tissues and transport them to the large veins. |
| Pulmonary Veins | Pulmonary veins help transport oxygenated blood to the heart after taking it from the lungs. |
| Systemic Veins | Systemic Veins are found throughout the human body, transporting deoxygenated blood to the heart for the purpose of purification. |
Risks of Arteries and Veins
Health problems with the veins and arteries can lead to:
- Varicose veins: Veins can sometimes have issues acquiring blood back up to your heart. It can cause varicose veins, which occur when the veins are bulging out of the skin. It mostly happens on the legs. Varicose veins are typically not serious. This often causes soreness and pain and occurs in overweight individuals.
- Artery plaque. Over the time period, cholesterol and other similar things, collectively termed plaque, can gradually build up within the arteries. This is called atherosclerosis. Plaque buildup in your arteries can potentially weaken blood flow throughout the body. It can cause heart disease, gangrene, and stroke.
Differences between Arteries and Veins
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There are many differences between Arteries and Veins. Some include:
| Classification | Arteries | Veins |
|---|---|---|
| Nature of blood | Carries oxygenated blood, the only exception being the pulmonary arteries. | Carries deoxygenated blood, the only exception being the four pulmonary veins. |
| Types of Walls | Consists of highly muscular, thicker and rigid walls. | Veins do not have rigid walls and are collapsible in the presence of blood. |
| Pulse Detectability | The pulse is detectable. | Pulse, here, is not detectable. |
| Systematic Solution | Responsible for 30% of the systematic circulation of blood in the body. | Responsible for 65% of the systematic circulation of blood in the body. |
| Location within the Body | Located in greater depths within the body. | Considerably located closer to the skin, especially superficial veins. |
| Colour | Red | Blue |
| Direction of Blood Flow | Heart to organs and tissues. | Organs and tissues to the blood. |
| Blood Pressure | High-pressure blood flow. | Low-pressure blood flow. |
| Oxygen and Carbon dioxide levels | High oxygen level with very low carbon dioxide. | Very low oxygen level with a high amount of carbon dioxide saturation. |
| Tunica Media | Tunica media contains smooth and elastic muscle tissues. | Tunica Media contains a couple of elastic fibres and is less muscular. |
| Lumen size | The lumen is narrow in size. | The lumen is wide in size. |
| Valves | No valves are present. | Valves are present. |
| Disease Risk Level | Are at a greater risk of diseases. For example, angina pectoris and atherosclerosis. | Considerably less risky towards diseases but they are present. For example, varicose veins. |
| Volume of Blood | Low in arteries. | Higher comparable to arteries. |
Things to Remember
- The three different layers of arteries and veins are: Tunica intima forming the innermost layers, Tunica media forming the middle layer, and Tunica adventitia forming the outermost layer of both veins and arteries.
- Veins collapse when there is no pressure or blood is not flowing through parts of them.
- Arteries have always a tight cylindrical shape.
- The primary difference between arteries and veins is the former carries oxygenated blood while the latter carries deoxygenated blood.
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Previous Year's Questions
- Blood capillaries are made of...[NEET 1993]
- Blood group AB has...[NEET 1991]
- An adult human with average health has systolic and diastolic pressures as… [NEET 1998]
- Blood pressure in the mammalian aorta is maximum during...[NEET 2015]
- Blood pressure in the pulmonary artery is...[NEET 2016]
- Breakdown product of haemoglobin is...[NEET 1988]
- Bundle of His is a network of...[NEET 2003]
- Arteries are best defined as vessels which....[NEET 2018]
- Arteries carry oxygenated blood except...[NEET 1989]
- Cells formed in bone marrow include...[NEET 1992]
- Compared to blood our lymph has...[NEET 2009]
Read Also: Bones of the Wrist
Sample Questions
Ques: Name the largest vein in the human body. (1 mark)
Ans: Inferior vena cava forms the largest vein in the human body carrying deoxygenated blood connected on the other side to the lower part of the body.
Ques: What is the largest artery in the human body? What does it do? (1 mark)
Ans: Aorta forms the largest artery in the human body. It is responsible for carrying oxygenated blood from the heart to the other body parts by dividing further into arteries. It’s the main outlet from the heart carrying oxygen-rich blood.
Ques: Is arterial blood loss similar to that from the veins? (1 mark)
Ans: No, since the blood pressure in the arteries is multiple times greater than that of blood flowing through veins, there is a greater chance of a high quantity of blood loss. It means less chance of clotting.
Ques: What happens when blood loss is from the veins? (1 mark)
Ans: Blood loss from the veins is much less dangerous as the blood pressure in the veins is much lower, so as the blood comes out there is a greater chance of clotting. Consequently, it means a lesser chance of blood loss.
Ques: In the human body what structure connects arteries and veins? (1 mark)
Ans: Arteries and veins are connected through capillaries which are like minute blood vessels.
Ques: How do Arteries and Veins work together? (1 mark)
Ans. Arteries and veins work together to help the blood to flow throughout the body. They connect via a structure known as capillaries. Capillaries can be defined as small webs of thin tubes which help to connect to an artery on one side and a vein on another.
Ques: Why is arterial blood loss more severe than blood loss from veins? (2 marks)
Ans: The blood pressure of arteries is known to be much greater than veins. When an artery is cut, blood typically spurts out with very high pressure, usually also very rapid in form. However, when a vein is cut, the blood oozes very slowly and has more time to clot. This is why it is less severe than arterial blood loss.
Ques: What are the different layers of arteries and veins? (3 marks)
Ans: There are three different layers of arteries and veins, which are:
- The innermost layer or Tunica Intima.
- The middle layer or Tunica Media.
- The outermost layer or Tunica Adventitia.
Ques: What are the differences between veins and arteries? (5 marks)
Ans: Some artery and vein differences are:
| Classification | Arteries | Veins |
|---|---|---|
| Nature of blood | Arteries carry oxygenated blood, the only exception being the pulmonary arteries. | Veins carry deoxygenated blood, the only exception being the four pulmonary veins. |
| Lumen Size | Narrow in size. | Wide in Size. |
| Wal Type | Contains highly muscular, thicker and rigid walls. | Veins do not possess rigid walls and are collapsible in the presence of blood. |
| Systematic Solution | 30% of the systematic circulation of blood in the body. | 65% of the systematic circulation of blood in the body. |
| Oxygen and Carbon dioxide levels | High oxygen level with very low carbon dioxide. | Extremely low oxygen level with high carbon dioxide saturation. |
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