Forces Across Membranes

Question 1

Why can there NOT be a difference between ICF and ECF osmolarity

Answer 1

Because water will always move down any osmotic gradient

It is always water that moves, not ions. Ions are non-penetrating particles and cannot cross membranes without some form of help – channel proteins, mediated carriers etc and only then move under specific conditions e.g. action potential of nerves.

Question 2

Where is the cell membrane located between the ISF, ICF or plasma

Answer 2

Between the ISF and ICF (ECF and ICF)

So the ICF is essentially in the cell