A vein is a conduit or blood vessel whose function is to carry deoxygenated blood from the blood capillaries to the heart. An artery is each of the vessels through which oxygenated blood flows from the heart to the capillaries in the body.
The circulatory system is designed to fulfill multiple functions, the main one is to transport blood throughout our body with the help of veins and arteries. Despite working in the same process, they work differently and have unique characteristics.
Humans have a greater number of veins , located in positions that vary depending on the person, unlike arteries.
In the systemic or greater circulation, the arteries carry blood abundant in oxygen and scarce in carbon dioxide. While the veins conduct blood abundant in carbon dioxide and low in oxygen, directed towards the organs in charge of disposing it, such as the lungs, kidneys or liver.
Veins and arteries have three layers which are the internal or intimate, the middle or muscular, and the external or adventitia.
| Veins | Arteries | |
|---|---|---|
| Definition | Ducts that carry blood from capillaries to the heart. | Blood vessels that carry blood from the heart to the rest of the body. |
| Features | Carry deoxygenated blood through the body. | Transport oxygenated blood. |
| Internal valves | Gifts. | Absent. |
| Structure | Scarce muscular layer, its walls are thinner and more superficial. | Thicker, more resistant and flexible muscle layer. |
| Characteristics of blood | The blood they carry is dark in color because it has no oxygen. | The blood that circulates in them is of a lighter color because it is oxygenated. |
| Graphic representation | The color blue is used to avoid confusion with the arteries. | They are represented by the color red. |
| Examples |
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Index
What are veins?
Veins are the high-capacity blood vessels that carry deoxygenated blood from the body’s capillaries to the heart. This transported blood is reoxygenated when it passes through the lungs.
The veins generally have more irregular shapes and a larger size than that of the corresponding arteries, they contain approximately 70% of the total volume of blood. In contrast, they are thinner-walled so they collapse more quickly when pressed.
There are also veins, like the pulmonary veins, that contain oxygenated blood that is carried to the heart and then to the rest of the body thanks to the umbilical veins and the aorta artery.
In the pulmonary circulation or minor circulation, the arteries carry oxygen-deficient blood from the heart to the lungs, and the pulmonary veins carry oxygenated blood from the lungs to the heart.
Both the blood samples and the supply of medicines and nutrients are carried out through the veins.
Veins are generally associated with arteries of the same name.
What are arteries?
The arteries are the vessels that carry oxygenated blood from the heart to the capillaries in the body.
Arteries are thick-walled blood vessels than veins, making them firmer . They carry blood that has been previously oxygenated in the lungs from the heart to the tissues with increased pressure during systole.
The further away the arteries are from the heart, their layer loses its elastic fibers, and these go from being elastic arteries to being known as muscular or distribution arteries .
As the heart pumps blood discontinuously, after an artery is distended by the flow carried by ventricular systole, its elastic nature creates a contraction of its wall, this is known as diastolic pressure. This process allows the uninterrupted flow of blood to the tissues, which does not occur in ventricular diastole.
The primary functions of the arteries are to deliver oxygen and nutrients to all cells, remove both carbon dioxide and waste products, and maintain physiological pH.
The arteries, having the highest pressure in the circulatory system, are the ones that produce the pulse where cardiac activity is reflected.
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