Blood vessels Flashcards
why is blood carried at a high pressure through the arteries?
blood has just been pumped out of the ventricles of the heart
why is the lumen in the arteries small?
to maintain the high pressure
why is the wall of the arteries relatively thick and contain collagen?
it gives it strength to withstand the high pressure
why do the arteries have elastic walls that stretch and recoil?
recoil maintains high pressure when the heart relaxes
why do the arteries contain smooth muscle that contract to constrict the artery?
in arterioles - limit blood flow to certain organs/tissues. regulates temperature
why is the endothelium folded in the arteries?
so they can unfold when the artery stretches
why are the endothelium walls one cell thick in the capillaries?
creates a short diffusion pathway
why is blood carried at a low pressure through the veins?
blood has travelled all around the body and is returning to the heart
why is the lumen large in the veins?
blood is at a low pressure and allows blood to keep flowing
why do veins contain collagen?
the walls are smaller than in arteries so collagen gives it strength
why do veins have elastic walls that stretch and recoil?
the recoil keep the blood flowing in the same way
why is endothelium folded in veins?
they unfold when veins stretch
why do veins contain valves?
prevents backflow of blood
why do skeletal muscles contracting aid the veins job?
helps to keep blood moving (especially from the lower body)
what is another name for the inside layer?
the tunica intima
