ultrafiltration is only selective by molecular size, not usefulness so many substances still need to be reabsorbed into the blood whilst others remain in the fluid in the tubule
what are the processes that occur at the PCT membrane?
Sodium ions are actively transported out of the PCT cells into the tissue fluid, glucose and amino acids in the PCT lumen then enter the PCT cells in with sodium ions by facilitated diffusion (high to low sodium concentration), glucose and amino acids then can diffuse into blood capillaries by facilitated diffusion
what ratio does the sodium potassium pump pump ions?
