Veins are floppy tubes that transport blood toward the heart. The outer layer of veins is a thick sleeve of connective tissue called the tunica adventitia or tunica externa. The tunica media or...
Venules are the microscopic vessels that continue from the capillaries and merge to form veins. Veins carry blood back to the atria, leading to the heart...
Veins: Blood vessel that carries blood back into the heart Usually oxygen poor blood is carried within these blood vessels (except pulmonary vein) They all have Valves to help prevent the back flow...
well if you are mean the size arteries, veins, venules, areteries then capilaries
if you mean from the heart ateries, artoriols, capilaries, venules then veins
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