Question

Substance X is freely filtered at the glomerulus. 3 mmole X is filtered, 2 mmole X is reabsorbed, and 2 mmole X is secreted per minute. How much X is excreted per minute?

1) 1 mmole
2) 2 mmole
3) 3 mmole
4) 4 mmole
5) 5 mmole

Answer 1

Substance X is freely filtered at the glomerulus. Out of the 3 mmole X that is filtered, 2 mmole X is reabsorbed and 2 mmole X is secreted per minute. Therefore, the correct answer is 0 mmole X.

Step-by-step explanation:

Substance X is freely filtered at the glomerulus. Out of the 3 mmole X that is filtered, 2 mmole X is reabsorbed and 2 mmole X is secreted per minute. To find out how much X is excreted per minute, we need to subtract the amount reabsorbed and the amount secreted from the amount filtered:

1. Amount filtered: 3 mmole X
2. Amount reabsorbed: 2 mmole X
3. Amount secreted: 2 mmole X

Total X excreted = Amount filtered - Amount reabsorbed - Amount secreted = 3 mmole X - 2 mmole X - 2 mmole X = -1 mmole X

Since we can't have a negative value for the amount excreted, the correct answer is 0 mmole X. Therefore, none of the options provided (1 mmole, 2 mmole, 3 mmole, 4 mmole, 5 mmole) are correct.