Question

The blood vessels, the arteries and veins of the body have some significant morphological differences. What are some of the most important and why do they exist?

Answer 1

Artery	Veins	Effects ( reasons why they exist)
Thicker muscular layer ---> more elastic than veins	Thinner muscular layer---> less elastic than an artery	This due to artery need to handle higher pressure of blood than a vein.When blood ejected at high pressure from the heart goes to the artery. So in artery muscular layer is thicker to handle the high blood pressure exerted by the stroke volume, whereas in veins the blood pressure is minimal. This features also makes the arteries as reservoir vessels which can accommodate extra blood for use in an emergency.
Does not have valves	Does have valves	In artery, the forward flow of blood is maintained by the pressure exerted by heart, but in veins that pressure is minimal and unable to propagate blood towards the heart. In the vein, there is two mechanism for propagation of blood, on is valves which prevent backflow of blood, and second one pulsation of arteries, which helps propagation of blood towards the heart.
Walls are more rigid due to thick muscular layer	Thinner due thin muscular layer	This makes arteries less vulnerable to superficial injuries than veins