Question

Given the equation for glomerular filtration {GFR = Kf [(Pg – Pb) – (Πg - Πb)]} explain how each factor in the equation impacts glomerular filtration

Answer 1

Ans:- GFR = FILTRATION CONSTANT X filtration pressure.

GFR = Kf [(Pg – Pb) – (Πg - Πb)]}

​​​​​​Where Kf= filtration constant

Filtration coefficient (Kf) a measure of a membrane's permeability to water; specifically, the volume of fluid filtered in unit time through a unit area of membrane per unit pressure difference, and it defined as the glomerular filtration rate (GFR) for both kidney per millimeter of mercury (mmHg) of filtration pressure. Therefore, the glomerular filtration rate is equal to the filtration pressure multiply the filtration coefficient.] The normal filtration coefficient for a healthy adult human is 12.5 ml per minute per mmHg of filtration pressure.

filtration pressure = Net force supporting filtration - net force opposing filtration.

= (Glomerular hydrostatic press+ capsular osmotic press). - ( capsular hydrostatic pressure + glomerular osmotic pressure)

GFR = Kf [(Pg – Pb) – (Πg - Πb)]}

Here :- Pg --- glomerular hydrostatic pressure= 60mmHg

Pb--- capsular hydrostatic press = 18 mmHg

πg --- glomerular osmotic pressure = 32mmHg

πb --- capsular osmotic press = OmmHg (since no protein is filtered out)

The process by which glomerular filtration occurs is called renal ultrafiltration. The force of hydrostatic pressure in the glomerulus (the force of pressure exerted from the pressure of the blood vessel itself) is the driving force that pushes filtrate out of the capillaries and into the slits in the nephron.

Osmotic pressure (the pulling force exerted by the albumins) works against the greater force of hydrostatic pressure, and the difference between the two determines the effective pressure of the glomerulus that determines the force by which molecules are filtered. These factors will influence the glomeruluar filtration rate, along with a few other factors.