The main constituents of glomerular filterate are

Analyze the question: It asks what the glomerular filtrate mainly contains. This is the fluid that is forced out of the blood in the glomerulus into the Bowman's capsule in the kidney.

Concept: Ultrafiltration

• Blood enters the glomerulus at high pressure through the wide afferent arteriole and leaves through the narrower efferent arteriole.
• This high pressure forces small molecules through the capillary walls into the Bowman's capsule.
• Small molecules pass through: water, glucose, amino acids, urea, mineral salts (such as Na⁺ and Cl⁻), and vitamins.
• Large molecules and cells stay in the blood: red blood cells, white blood cells, platelets, and plasma proteins.

Solution: Check each option.

• A. Blood and water: Wrong. Blood as a whole (with its cells) is not filtered.
• B. Blood and urea: Wrong, for the same reason.
• C. Glucose and water: Both are in the filtrate, but glucose is later fully reabsorbed. It is not a main waste constituent of the filtrate, so this is incomplete as a description of what is being filtered out.
• D. Salt and blood: Wrong, because blood is not present.
• E. Water and urea: Both are present in the filtrate. Water is the bulk of it, and urea is the main nitrogenous waste the kidney removes.

Option C is the closest competitor, since glucose really is in the filtrate. But the question is asking for the main constituents, and water and urea are the key components, with urea being the waste product the kidney is filtering out.

Tip: Remember that the glomerulus filters by size. Anything small (water, glucose, salts, urea, amino acids) passes through, while blood cells and proteins are too large. Whenever an option contains "blood", eliminate it right away, because the filtrate is blood minus its cells and proteins.