Do you know how our blood circulates throughout our bodies? Blood is transported through blood vessels, which are a component of the circulatory system. The heart uses a network of blood arteries to transport blood throughout the body. Blood veins transport blood to and from our billions of cells, providing nourishment and removing waste. The cardiovascular system is made up of blood, the heart, and blood arteries.
Based on their shape and function, blood vessels are classified into three types: arteries, veins, and capillaries. The study of blood vessels is known as angiology.
Arteries
Arteries are the blood veins that carry oxygenated blood from the heart to the other organs.
The arteries are basically used to transport the oxygenated blood, however the pulmonary and umbilical arteries are exceptions, since they used to carry deoxygenated blood.
The arteries are essential for controlling blood flow into the tissue capillaries. At any given moment, the arterial system contains around 10% of total blood volume.
Types of Arteries
1. Elastic arteries: Elastic arteries are large-sized conducting arteries. During systole, their walls extend to meet the rapid pressure of blood emerging from the left ventricle of the heart (contraction of the heart to pump out the blood).
Example: Aorta
2. Muscular arteries: Muscular arteries are made up of smooth muscles that may readily expand and contract depending on the amount of blood in the vessel and connect elastic arteries and arterioles.
3. Arterioles: Arterioles are small blood channels that branch from arteries and have thin walls. Through these thin walls, oxygen and nutrients enter into tissues delivered by the blood.
Structure of Arteries
Arteries are three-layered tube-like structures.
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Outer Layer: The outer layer is composed of connective tissues, collagen fibres, and elastic fibres. The blood vessels are supported by this layer.
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Middle layer: Smooth muscles, collagen fibres, and a greater amount of elastic fibres make up this layer. This layer is responsible for the strength and elasticity of the skin.
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Inner Endothelium: It is made up of exceptionally smooth epithelial cells that serve to reduce friction.
Veins
Veins are elastic vessels that transport blood from various sections of the body to the heart, i.e. they transport blood towards the heart.
Vein walls have less smooth muscles and connective tissues than artery walls. As a result, the walls of veins are thinner than those of arteries.
If we compare, the pressure inside the veins is lower than that of inside the arteries.
Except for the pulmonary vein, which transports oxygenated blood from the lungs to the heart, all veins transmit deoxygenated blood.
Veins have valves (in the tunica intima layer) to prevent blood from flowing backward.
Types of Veins
1. Deep veins: As the name implies, they are found at deeper depths within the body, as compared to veins visible beneath the skin.
2. Superficial veins: These are veins that are visible just under the skin and are not found in deep areas.
3. Venules: Venules are the smallest veins in the body, collecting deoxygenated blood from tissues and transporting it to larger veins.
Structure of veins
The walls of your veins are composed of three distinct layers:
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Tunica externa: This is the thickest and most outer layer of the vein wall. It is largely composed of connective tissue. The tunica externa also contains vasa vasorum, which are microscopic blood vessels that deliver blood to the walls of your veins.
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Tunica media: The tunica media is the layer in the middle. It is thin and has a lot of collagen in it. The collagen is one of the major components of connective tissue.
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Tunica intima: This is the deepest stratum. It consists of a single layer of endothelial cells and connective tissue. This layer has one-way valves on occasion, particularly in the veins of your arms and legs. Blood cannot flow backwards through these valves.
Arteries and veins difference
|
S.NO |
Arteries |
Veins |
|
1 |
Transports blood away from the heart. |
Transports blood to the heart. |
|
2 |
Except pulmonary arteries, all arteries transport the oxygenated blood. |
Except for the pulmonary vein, all veins transport deoxygenated blood. |
|
3 |
The walls are thick and elastic, and the lumen is small. |
They have thinner, less elastic walls and a large lumen. |
|
4 |
Tunica media is dense here. |
Tunica media is thin here. |
|
5 |
There is no need for valves to prevent blood backflow. Except for the aorta and the pulmonary artery, all arteries have aortic and pulmonary valves. |
Except for the pulmonary vein, all veins have valves to prevent the blood backflow. |
|
6 |
Tunica interna has a strong elastic membrane and longer endothelial cells. |
Tunica interna has a thin elastic membrane and shorter endothelial cells. |
|
7 |
The blood pressure is really high here. |
Here, the blood pressure is low. |
|
8 |
Because blood pressure is high here, arteries are deep-seated. This prevents it from being damaged and losing blood. |
Because the blood pressure is low here, the veins are superficial. Superficial veins help in bodily cooling. |
Conclusion
Blood is transported through blood vessels, which are a component of the circulatory system. The heart uses a network of blood arteries to transport blood throughout the body. The cardiovascular system is made up of blood, the heart, and blood arteries. Arteries are the blood veins that carry oxygenated blood from the heart to the other organs. They generally transport oxygenated blood, with the exception of the pulmonary and umbilical arteries, which carry deoxygenated blood. Veins are elastic vessels that transport blood from various sections of the body to the heart, i.e.they transport blood towards the heart. If we compare, the pressure inside the veins is lower than that of inside the arteries.