Which of the following are components of glomerular filtrate?

Step 1: Analyze the question The question asks what makes up the glomerular filtrate, which is the fluid that passes from the blood in the glomerulus into the Bowman's capsule of the nephron.

Step 2: The concept: ultrafiltration Blood enters the glomerulus at high pressure. This is because the afferent arteriole (entering) is wider than the efferent arteriole (leaving). The pressure forces small molecules through the capillary walls and into the Bowman's capsule.

• Small molecules pass through: water, glucose, amino acids, mineral salts (e.g. Na⁺, Cl⁻), urea, and other nitrogenous wastes.
• Large molecules and cells are held back: red blood cells, white blood cells, platelets, and plasma proteins (such as albumin and globulins) are too big to pass.

So the glomerular filtrate is basically blood plasma without the plasma proteins, with no cells.

Step 3: Check each option

• A. Wrong. Mineral salts do pass into the filtrate, so they are not excluded.
• B. Wrong. The filtrate contains much more than water and salt. It also has glucose, amino acids, and urea.
• C. Correct. It contains everything in the blood except the plasma proteins and the blood cells.
• D. Wrong. Blood cells cannot pass through the filtration membrane. Their presence in urine would indicate kidney damage.

Step 4: Answer The correct option is C.

Exam tip: Remember "Filtration is by size." Anything small (water, glucose, amino acids, salts, urea) goes through. Anything big (cells and proteins) stays in the blood. Later, in the proximal convoluted tubule, useful substances like glucose and amino acids are reabsorbed. This is why healthy urine has no glucose and no protein.