When glomerular filtration is working correctly, which of the following does not enter the nephron: glucose, red blood cells, or sodium?
When glomerular filtration is working correctly the red blood cells do not enter the nephron.
The factors determining the permeability and selectivity of the glomerulus are :
A) presence of negative charge of the basement membrane and the podocytic epithelium.
B) effectively small pore size of the glomerular wall.
As a result, small or positively charged molecules will pass through freely. For example small ions like sodium and potassium pass freely but RBC's , large proteins like albumin and haemoglobin have practically no permeability at all.