Which of the following favors filtration at the arteriolar end of the capillary bed?
High-Yield Explanation
Ans. is 'b' i.e. Increase in hydrostatic pressure of capillaries The rate of filtration at any point along a capillary depends on balance of Starling forces - (A) Hydrostatic pressure gradient: (B) Osmotic pressure gradient:(Hydrostatic press, of capillaries (Plasma colloid Osmotic pressure minus hydrostatic press, of minus interstitial fluid colloid osmoticinterstitium) pressure)Net filtration press. (NFP) = Hydrostatic press, gradient - Osmotic press, gradientIf NFP is positive then there is outward movement of fluid across the capillaries & if negative then inward movement of fluid occurs.* In normal conditionsAt the arteriolar end the hydrostatic pressure gradient is more than osmotic press, gradient so there is outward movement of fluid into the interstitial space &At the venular end the osmotic press, gradient exceeds hydrostatic press, gradient (filtration pressure) resulting into fluid movement into the capillary.Filtration rate = Kf x NFPKf - Capillary filtration coefficientNFP - Net filtration pressure Capillary filtration coefficient is proportionate to the permeability of the capillary wall & the area available for filtration.Fluid pressure and colloid osmotic pressure forces operate at the capillary membrane, tending to move fluid either outward or inward through the membrane pores.