The glomerular filtrate contains all except –
**Core Concept**
Glomerular filtration is the process by which the glomeruli in the kidneys filter the blood to produce the glomerular filtrate, which then passes through the renal tubules for further modification before being excreted as urine. The glomerular filtrate contains water, ions, glucose, amino acids, and other small molecules that have passed through the glomerular capillary membrane.
**Why the Correct Answer is Right**
The glomerular filtrate contains a variety of substances that have been filtered from the blood, including water, ions (such as sodium and chloride), glucose, amino acids, and other small molecules. However, the glomerular filtrate does not contain proteins, blood cells, and other larger molecules that are too large to pass through the glomerular capillary membrane. This is due to the selective permeability of the glomerular basement membrane, which allows smaller molecules to pass through while restricting larger ones.
**Why Each Wrong Option is Incorrect**
**Option A:** Incorrect because the glomerular filtrate contains glucose, which is a small molecule that has passed through the glomerular capillary membrane.
**Option B:** Incorrect because the glomerular filtrate contains ions, such as sodium and chloride, which are essential for maintaining proper fluid balance and pH levels.
**Option C:** Incorrect because the glomerular filtrate contains amino acids, which are small molecules that have been filtered from the blood.
**Clinical Pearl / High-Yield Fact**
One important clinical correlation to remember is that the glomerular filtration rate (GFR) can be used to assess kidney function. A decreased GFR can indicate kidney damage or disease, which can lead to complications such as fluid overload, electrolyte imbalances, and acid-base disturbances.
**Correct Answer: D.**