Question

Which one of the following does not filter out from blood to Bowman’s capsule in glomerular ultrafiltration?
A. Amino acids
B. Polypeptide
C. Glucose
D. Fatty acids

Answer 1

Glomerular filtration is the first step in urine formation. The removal of fluid from a person is the main function of kidneys, which is replaced by dialysis when kidneys do not function properly. The ultrafiltration does not filter very large molecules.

Complete step by step answer: The very first step for the formation of urine is glomerular filtration, which constitutes the basic physiologic function of the kidney where some components are removed like fluids, ions, glucose and waste products from the glomerular capillaries. The term “ultrafiltration” refers to the passage of protein-free fluid from the glomerular capillaries into Bowman’s space. The volume of filtrate developed by the pair of kidneys per minute is termed as glomerular filtrate rate (GFR). GFR is influenced by multiple factors, such as at tissue capillary beds. Glomerular filtration occurs when glomerular (blood) hydrostatic pressure exceeds the hydrostatic pressure of the glomerular capsule and the blood colloid osmotic pressure. The addition of all the influences including the osmotic and hydrostatic results in a net filtration pressure (NEP). The components mentioned above like amino acids, glucose, fatty acid along with water are absorbed and reabsorbed during the glomerular filtration except for the polypeptide because of its complex structure.
Hence, the correct answer is option B.

Note: The way to calculate the NFP is as follows:
NFP=Glomerular blood hydrostatic pressure (GBHP) – [capsular hydrostatic pressure (CHP) + blood colloid osmotic pressure (BCOP)] = 10mm Hg.
That is, NFP=GBHP – [CHP+BCOP] = 10mm Hg.
As the value of GBHP is 55, CHP is 15 and BCOP is 30 then this formula is used and the value is taken as 10mm Hg.
NFP=55-[15+30]=10mm Hg.