Question

Which of the equations below describes the calculation of glomerular filtration pressure (BC = Bowman's capsule and GC = glomerular capillary)?

1) (PGC + πBC) - (PBC + πGC)
2) (PBC + πBC) - (PGC + πGC)
3) (PGC + πGC) - (PBC + πBC)
4) (PGC + PBC) - (πGC + πBC)
5) (PBC + πGC) - (PGC + πBC)

Answer 1

The correct equation for calculating glomerular filtration pressure is (PGC + πBC) - (PBC + πGC); it accounts for the hydrostatic and osmotic pressures in the glomerular capillary and Bowman's capsule.

Step-by-step explanation:

The equation describing the calculation of glomerular filtration pressure (GFP) in the context of the pressures in Bowman's capsule (BC) and the glomerular capillary (GC) is option 1: (PGC + πBC) - (PBC + πGC). This equation takes into account the glomerular blood hydrostatic pressure (GBHP), which is equivalent to PGC, the capillary hydrostatic pressure (CHP), which is equivalent to PBC, and the blood colloid osmotic pressure (BCOP), which is equivalent to πGC. Based on the reference information given, net filtration pressure (NFP) is calculated as GBHP - (CHP + BCOP), typically resulting in a value of 10 mm Hg, which is the underlying pressure driving filtration across the membrane.