What three factors influence glomerular filtration?

Glomerular filtration is a crucial process in the kidneys where blood is filtered to form urine, and it is influenced by specific physical and biochemical factors. The correct choice highlights three primary determinants: pressure, negative charge, and size of the molecule.

Pressure plays a vital role in glomerular filtration; specifically, it refers to the hydrostatic pressure in the glomerular capillaries. This pressure drives the water and solutes from the blood into the Bowman’s capsule, overcoming the opposing forces that pull fluid back into the capillaries.

The negative charge aspect is significant because the glomerular filtration barrier comprises negatively charged structures, such as heparan sulfate in the glomerular basement membrane. Molecules with a negative charge are often repelled by these barriers, limiting their passage into the filtrate. In contrast, positively charged molecules can pass through more easily, which affects the selectivity of the filtration process.

Lastly, the size of the molecule is critical; large molecules, such as most proteins, are generally retained in the bloodstream and do not cross the filtration barrier, while smaller molecules can be filtered out. This size selectivity helps to ensure that essential proteins remain in circulation while waste products and excess substances are excreted.

Understanding