Difference between Arteries and Veins?
In: Biology
Some A-level revision for me here, so here we go:
TL;DR: The most basic difference is Arteries carry oxygenated blood Away from the heart towards the body tissue. VeINs transport deoxygenated blood INto the heart.
More detail: Arteries are large vessels which split into arterioles (smaller arteries) which split into smaller capillaries which transfer oxygen into cells and take out carbon dioxide.
The capillaries then join up into Venules (smaller veins) which join up to form Veins.
The main Artery is the Aorta and the main Vein is the Vena Cava. Imagine Veins and Arteries like Motorways (Highways if you’re from Freedom Land) and Venules/Arterioles like Dual Carriageways (No idea the American Equivalent of these) and Capillaries like residential roads. In essence, Veins and Arteries take lots of blood, super fast to where it needs to go. Arterioles, Venules, Capillaries all take it to more precise locations.
That’s function down, now comes structure. This stuff is a lot more dense so you can skip over it.
Your blood vessels are arranged as so:
The Lumen-the gap in the middle
Smooth Muscle-Muscular tissue that can contract and relax to control the diameter of the blood vessel
Elastic Tissue-this recoils to smooth out pressure surges and prevent blood vessels from bursting
Outer layer-tough to stop bursting
Arteries and Veins have the same overall diameter but the lumen of the Veins is wider so blood travels at lower pressure. The Lumen is wider because the aforementioned tissue above isn’t as thick in veins.
Arteries have a thick smooth muscle layer because they need to contract and relax to control the flow of blood into tissues. Relaxing the muscle means more blood enters tissues (if you’re exercising this will happens as your cells need more oxygen). Arteries also have thicker elastic tissue to cope with higher pressure due to the narrow lumen.
Veins on the other hand, don’t control blood flow into tissue and carry low pressure blood so have thin smooth muscle and elastic tissue. Veins also have valves to prevent blood flowing backwards due to the low pressure.
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