Differences Between Arteries And Veins

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Arteries and veins transport blood in two distinct circuits: the systemic circuit and the pulmonary circuit.  Systemic arteries provide blood rich in oxygen to the body’s tissue. The blood returned to the heart through systemic veins has less oxygen since much of the oxygen carried by the arteries has been delivered to the cells. In contrast, in the pulmonary circuit, arteries carry blood low in oxygen exclusively to the lungs for gas exchange. Pulmonary veins then return freshly oxygenated blood from the lungs to the heart to be pumped back out into systemic circulation.

What Are Arteries?

An artery is a blood vessel that carries blood away from the heart to other parts of the body. Almost all arteries carry blood with a lot of oxygen in it. The only arteries that do not carry oxygen-rich blood are the pulmonary artery and (in a fetus) the umbilical artery.

Because arteries are moving blood being pumped out by the heart, the walls of arteries are thicker and more elastic than those of veins. This is because the blood in the arteries is passing through with a higher pressure than in veins. The thick, elastic walls of arteries accommodate that pressure.

Arteries are usually found deeper in the body, but provide a detectable pulse. They also do not have valves and rely on blood pressure to keep blood flowing in the right direction. In order to control blood flow through vessels, the smooth muscle surrounding the arteries can constrict which causes vasoconstriction or they can relax which causes vasodilation.

Types of Arteries

There are three types of arteries

  • Elastic arteries
  • Muscular arteries
  • Arterioles

Examples of major artery vessels include:

  • Aorta
  • Carotid artery
  • Subclavian artery
  • Bronchial artery
  • Celiac trunk
  • Superior/inferior mesenteric artery
  • Femoral artery

What You Need To Know About Arteries

  1. Arteries transport blood rich with oxygen away from the heart to the other tissues of the body.
  2. Pressure of blood flowing through the arteries is high.
  3. Pulmonary arteries transport deoxygenated blood from the heart’s right ventricle to the lungs.
  4. Arteries have thick elastic muscular walls to withstand the pressure of blood flowing throw them.
  5. Arteries are narrower when compared to veins, they approximately 4mm in diameter.
  6. Arteries are usually positioned deeper within the body.
  7. Arteries do not have Semilunar valves and rely on blood pressure to keep blood flowing in the right direction.
  8. Pulsation is detectable in the arteries with every heartbeat.
  9. Types of arteries are pulmonary and system arteries.
  10. Artery is made up of rigid walls.
  11. Arteries carry about 30% of the systemic circulation of blood in human.
  12. Carbon dioxide (CO2) level in arterial blood is very low.
  13. Arteries empty up at the time of death.
  14. Some of the diseases that affect arteries include: Atherosclerosis, Angina Pectoris, Artherogenesis-myocardial ischemia.
  15. In arteries, Tunica interna has more elongated endothelial cells. Elastic membranes are well developed.
  16. Tunica media is composed of elastic and smooth muscle tissues.
  17. Arteries have a narrow lumen.
  18. Walls of artery are elastic.
  19. The largest artery is referred to as aorta whereas smallest artery is referred to as Arterioles.
  20. If arterial wall is injured, the blood comes out like a ‘’fountain’’ in a large area all around the artery.

What Are Veins?

Veins are blood vessels that carry blood towards the heart. Most veins carry deoxygenated blood from the tissue back to the heart with exception of the pulmonary and umbilical veins. Veins are usually close to the surface of the skin but do not give off a pulse. Most veins consist of one-way valves that prevent blood from flowing in the reverse direction.

Veins are also referred to as capacitance vessels because they contain 60% of the body’s blood volume. In systemic circulation, oxygenated blood is pumped by the left ventricle through the arteries to the muscles and organs of the body, where its nutrients and gases are exchanged at capillaries. The blood then enters venules, then veins filled with cellular waste and carbon dioxide. The deoxygenated blood is taken by veins to the right atrium of the heart, which transfers the blood to the right ventricle, where it is then pumped through the pulmonary arteries to the lungs. In pulmonary circulation, the veins return oxygenated blood from the lungs to the left atrium which empties into the left ventricle, completing the cycle of blood circulation.

Types Of Veins

There are four types of veins, they include;

  • Deep veins
  • Superficial veins
  • Pulmonary veins
  • Systemic veins

Examples of major veins

  • Vena cava
  • Jugular vein
  • Subclavian vein
  • Bronchial vein
  • Azygos vein
  • Renal vein
  • Femoral vein

What You Need To Know About Veins

  1. Veins transport blood that has been depleted of oxygen from the tissue of the body back to the heart.
  2. Pressure of blood flowing through the vein is low.
  3. Pulmonary veins transport oxygenated blood from the lungs to the heart’s left atrium.
  4. Veins have thin non-elastic less muscular walls.
  5. Veins are relatively wider when compared to arteries, they approximately 5mm in diameter.
  6.  Veins are usually positioned closer beneath the surface of the skin.
  7. Veins have Semilunar valves that ensure blood flows in the right direction.
  8. Pulse is not detectable in the vein.
  9. Types of veins are pulmonary veins, systemic veins, superficial veins and deep veins.
  10. Veins are made up of collapsible walls.
  11. Veins carry about 65% of the systemic circulation of blood in human.
  12. Carbon dioxide (CO2) level in veins is very high.  
  13. Veins get filled up at the time of death.
  14. Some of the diseases that affect veins include: Deep vein thrombosis, varicose veins.
  15. Tunica interna in veins has less flat endothelial cells. Elastic membranes are not very well developed.
  16. Tunica media is composed of few elastic fibres and is less muscular.
  17. Veins have a wider lumen.
  18. Walls of veins are less elastic.
  19. The largest vein is referred to as Vena cava whereas the smallest vein is referred to as Venules.
  20. If vein wall is injured, blood comes out, collects in a pool in a small area around vein.

Also Read: Difference Between Open And Closed Circulatory System

Difference Between Arteries And Veins In Tabular Form

BASIS OF COMPARISON ARTERIES VEINS
Description Arteries transport blood rich with oxygen away from the heart to the other tissues of the body.   Veins transport blood that has been depleted of oxygen from the tissue of the body back to the heart.  
Pressure Of Blood Pressure of blood flowing through the arteries is high.   Pressure of blood flowing through the vein is low.  
Pulmonary Artery/Veins Pulmonary arteries transport deoxygenated blood from the heart’s right ventricle to the lungs.   Pulmonary veins transport oxygenated blood from the lungs to the heart’s left atrium.  
Muscular Walls Arteries have thick elastic muscular walls to withstand the pressure of blood flowing throw them.   Veins have thin non-elastic less muscular walls.  
Width Arteries are narrower when compared to veins, they approximately 4mm in diameter.   Veins are relatively wider when compared to arteries, they approximately 5mm in diameter.  
Location Arteries are usually positioned deeper within the body.   Veins are usually positioned closer beneath the surface of the skin.  
Similunar Arteries do not have Semilunar valves and rely on blood pressure to keep blood flowing in the right direction.   Veins have Semilunar valves that ensure blood flows in the right direction.  
Pulse Detection Pulsation is detectable in the arteries with every heartbeat.   Pulse is not detectable in the vein.  
Types Types of arteries are pulmonary and system arteries.   Types of veins are pulmonary veins, systemic veins, superficial veins and deep veins.  
Nature Of Walls Artery is made up of rigid walls.   Veins are made up of collapsible walls.  
Percentage Of Systemic Circulation Arteries carry about 30% of the systemic circulation of blood in human.   Veins carry about 65% of the systemic circulation of blood in human.  
Carbon Dioxide Level Carbon dioxide (CO2) level in arterial blood is very low.   Carbon dioxide (CO2) level in veins is very high.   
At The Time Of Death Arteries empty up at the time of death.   Veins get filled up at the time of death.  
Diseases Some of the diseases that affect arteries include: Atherosclerosis, Angina Pectoris, Artherogenesis-myocardial ischemia.   Some of the diseases that affect veins include: Deep vein thrombosis, varicose veins.  
Tunica Interna In arteries, Tunica interna has more elongated endothelial cells. Elastic membranes are well developed.   Tunica interna in veins has less flat endothelial cells. Elastic membranes are not very well developed.  
Tunica Media Tunica media is composed of elastic and smooth muscle tissues.   Tunica media is composed of few elastic fibres and is less muscular.  
Lumen Arteries have a narrow lumen.   Veins have a wider lumen.  
Elasticity Of Walls Walls of artery are elastic.   Walls of veins are less elastic.  
Largest & Smallest  Vein And Artery   The largest artery is referred to as aorta whereas smallest artery is referred to as Arterioles.   The largest vein is referred to as Vena cava whereas the smallest vein is referred to as Venules.  
Injury If arterial wall is injured, the blood comes out like a ‘’fountain’’ in a large area all around the artery.   If vein wall is injured, blood comes out, collects in a pool in a small area around vein.  

Similarities Between Arteries And Veins

  • Both vein and artery carries blood in one direction (uni-directional).
  • Both are made up of layers of cells.
  • Arteries and vein show vasoconstriction and vasodilation to adjust the blood pressure according to the action of hormones and neurotransmitters.
  • They both show anastomosis.
  • Arteries and veins are made up of three layers of cells referred to as Tunica externa (external layer), tunica media (middle layer) and tunica interna (internal layer).
  • Both transport blood.