Question

What is the average concentration of chloride ions in cerebrospinal fluid per 100 ml is

Answer 1

The correct answer should be - 371 mg or 10.5 meq.

Cerebrospinal fluid is an autonomous fluid present only in the brain. Since the blood and the CSF have restrictions about the diffusion of substances in between them, the CSF tends to have its own concentration of ions and substances.

Although the sodium ions and the osmotic pressure in the CSF is same as that of the plasma, the chloride ion concentration in the CSF is 15% lesser than that in the plasma.

Studies show that the total chloride ion concentration in CSF is around 105 milliequivalents per litre of CSF. So for 100 ml of CSF, the chloride ion concentration should be around - 10.5 meq.

By converting meq to mg, we get the value for chloride ions as - 371 mg. The atomic weight of Chlorine has been taken as 35.4 and its valency is 1.