▁the ▁wall ▁layer . ▁ ▁The ▁blood ▁resistance ▁law ▁appears ▁as ▁R ▁adapted ▁to ▁blood ▁flow ▁profile ▁: ▁▁▁ ▁where ▁▁ ▁R ▁= ▁resistance ▁to ▁blood ▁flow ▁ ▁c ▁= ▁constant ▁coefficient ▁of ▁flow ▁ ▁L ▁= ▁length ▁of ▁the ▁vessel ▁▁ η ( δ ) ▁= ▁vis cos ity ▁of ▁blood ▁in ▁the ▁wall ▁pl asma ▁release - cell ▁layer ing ▁ ▁r ▁= ▁radius ▁of ▁the ▁blood ▁vessel ▁▁ δ ▁= ▁distance ▁in ▁the ▁pl asma ▁release - cell ▁layer ▁ ▁Blood ▁resistance ▁var ies ▁depending ▁on ▁blood ▁vis cos ity ▁and ▁its ▁plug ged ▁flow ▁( or ▁she ath ▁flow ▁since ▁they ▁are ▁complement ary ▁across ▁the ▁vessel ▁section ) ▁size ▁as ▁well , ▁and ▁on ▁the ▁size ▁of ▁the ▁vessels . ▁Assuming ▁steady , ▁l amin ar ▁flow ▁in ▁the ▁vessel , ▁the ▁blood ▁vessels ▁behavior ▁is ▁similar ▁to ▁that ▁of ▁a ▁pipe . ▁For ▁instance ▁if ▁p 1 ▁and ▁p 2 ▁are ▁press ures ▁are ▁at ▁the ▁ends ▁of ▁the ▁t ube , ▁the ▁pressure ▁drop / gradient ▁is : ▁ ▁The ▁larger ▁ar ter ies , ▁including ▁all ▁large ▁enough ▁to ▁see ▁without ▁magn ification , ▁are ▁condu its ▁with ▁low ▁v asc ular ▁resistance ▁( ass uming ▁no ▁advanced ▁a ther os cler otic ▁changes ) ▁with ▁high ▁flow ▁rates ▁that ▁generate ▁only ▁small ▁dro ps ▁in ▁pressure . ▁The ▁smaller ▁ar ter ies ▁and ▁ar ter i oles ▁have ▁higher ▁resistance , ▁and ▁confer ▁the ▁main ▁blood ▁pressure ▁drop ▁across ▁major ▁ar ter ies ▁to