d)arteries arteries ??? ??? ??? the two-way exchange of substances between blood and body cells occur only through capillaries ??? ??? ??? large molecules such as peptides and proteins move into and out of the bloodstream by way of fenestrated capillaries ??? ??? ??? the alteration of blood flow due to actionn of precapillary sphincters is vasomotion ??? ??? ??? the blood vessels that collect bloo