▁nut ri ents , ▁h orm ones , ▁met abol ic ▁was tes , ▁O 2 ▁and ▁CO 2 ▁throughout ▁the ▁body ▁to ▁maintain ▁cell - level ▁met abol ism , ▁the ▁reg ulation ▁of ▁the ▁p H , ▁os m otic ▁pressure ▁and ▁temperature ▁of ▁the ▁whole ▁body , ▁and ▁the ▁protection ▁from ▁micro b ial ▁and ▁mechanical ▁har ms . ▁ ▁Blood ▁is ▁a ▁non - New ton ian ▁fluid , ▁best ▁studied ▁using ▁r he ology ▁rather ▁than ▁hyd rod ynam ics . ▁Blood ▁vessels ▁are ▁not ▁rig id ▁tub es , ▁so ▁classic ▁hyd rod ynam ics ▁and ▁flu ids ▁mechan ics ▁based ▁on ▁the ▁use ▁of ▁classical ▁vis com eters ▁are ▁not ▁capable ▁of ▁explaining ▁hem od ynam ics . ▁ ▁The ▁study ▁of ▁the ▁blood ▁flow ▁is ▁called ▁hem od ynam ics . ▁The ▁study ▁of ▁the ▁properties ▁of ▁the ▁blood ▁flow ▁is ▁called ▁hem or he ology . ▁ ▁Blood ▁ ▁Blood ▁is ▁a ▁complex ▁liquid . ▁Blood ▁is ▁composed ▁of ▁pl asma ▁and ▁formed ▁elements . ▁The ▁pl asma ▁contains ▁ 9 1 . 5 % ▁water , ▁ 7 % ▁prote ins ▁and ▁ 1 . 5 % ▁other ▁sol utes . ▁The ▁formed ▁elements ▁are ▁plate lets , ▁white ▁blood ▁cells ▁and ▁red ▁blood ▁cells , ▁the ▁presence ▁of ▁these ▁formed ▁elements ▁and ▁their ▁interaction ▁with ▁pl asma ▁mole cules ▁are ▁the ▁main ▁reasons ▁why ▁blood ▁diff ers ▁so ▁much ▁from ▁ideal ▁Newton ian ▁flu ids . ▁ ▁Vis cos ity ▁of ▁pl