Arteries and veins are the pipe like vessels which carry blood in the body.
These are two similar yet different types of blood vessels forming the parts of circulatory system.
In general, arteries carry away the blood pumped by heart during systole.
These arteries branch out further as arterioles.
These arterioles further branch out into capillaries.
These capillaries are so minute and pass in between cells to supply blood and nutrients to the deeper most part of the tissues.
These capillaries again collect waste from the cell and tissues surroundings into blood.
They then converge to form venules which are bit bigger in size.
These venules further converge to form veins.
These veins further form superior and inferior vena-cava which pour this impure blood into the organ heart.
Thus arteries carry pure blood from heart to tissues while veins return impure blood. But interestingly, a pulmonary vein brings pure oxygenated blood from lungs into the heart.
While a pulmonary artery carries impure blood (carbonated) from heart to the lungs. So these two are different from rest of the blood veins and arteries in function.
Besides there are also anatomical structural differences in between them. These differences are meant to keep them safe, perform their function efficiently and also to minimize work load on heart and energy requirement of the body to circulate the blood.
Difference Between Arteries and Veins
Arteries receive blood due to pressure from heart while veins do not have that pressure. So the differences are as
|Blood||They carry pure blood rich in nutrients||They carry impure blood rich in waste of the body.|
|Wall thickness||Arteries have thicker wall||The veins have thin walls|
|Body location||They are deep seated in the body.||They are peripherally loacted in the body. Hence we can see blood vessels in the back of hands, on face, legs etc.|
|Blood flow||Blood flows by pulsatile manner corresponding to heart beat.||No pulse, blood flows uniforms|
|Flow pressure||Blood flows due to pumping pressure of heart. So pressure is high.||Blood flows due to capillary action of the veins. Pressure is low comparatively|
|Oxygen level||Oxygen levels is quite high in arterial blood||Oxygen level is low comparatively|
|Carbon-dioxide level||CO2 level is low in arterial blood||CO2 level is high in venous blood,|
|Flow direction||From heart to the tissues||From tissue to the heart.|
|Color||They are dark reddish color||They have bluish red color.|
|Valves||There are no valves in the artery vessels.||There are valves in the veins allowing blood to flow in upward direction.|
|Diseases||Arteries are susceptible to diseases like angina pectoris, atherosclerosis||Less susceptible to diseases and includes diseases like varicose veins.|
Thickness: As seen in the differences above, arteries have hick walls as they have to bear the systolic pressure. Also they have more muscle mass in the walls to propagate the pulse further due to elasticity. This helps the blood move fast in the vessel to the tissues. Hence we can measure heart pulse from wrist artery. Further thick wall may minimize he chances of oxygen and nutrients to diffuse to the surroundings.
Body location: Their deep seated or location in the body may also be to prevent damage to them in case of injury to the body. As their damage can destroy the organ receiving the blood faster. But for veins there is another alternate called lymph vessels which also carry waste from tissues. So damage can to them can be less severe. Only condition is there should be no hemorrhage.
Pressure: Pressure in arteries is more than in veins.
Valves: Help in preventing the blood in backward flow as veins rely on capillary action. Since there is change in gravitational pressure when sitting and standing up, there chances of varying in flow pressure. So valves prevent back flow of blood in veins. This is not required in arteries.
Color: The arteries are dark reddish due to oxygenated blood. While for veins, bluish red is due to oxygenated blood.
Diseases: Arteries are thick and carry nutrition. So, nutrition born disease occurs due to accumulation of fat. While for veins it is rare but occurs due to obstruction or physical damage to them.
Thus arteries and veins have functional and structural differences to suit the needs of the body.