Isotonic vs isosmotic

Question

what is the difference between an isotonic and an isosmotic solution?

Answer 1

ISOTONIC is when a solution has the same salt concentration as the blood and cells of the human body.

ISOSMOTIC is when two solutions have the same number of solutes.

Answer 2

Roughly speaking, I think isotonic is regarding to the salt concentration (Na, Cl, K and so on)  whereas iso-osmotic is the potential of the water to go through by osmosis is the same.

Answer 3

Isotonic is related to the ionic strength or the concentration of IONS in solution.  For example, a solution that is 154 mM NaCl is isotonic (for humans, at least).  Now, take a solution that has no ions, for example, sucrose.  Iso-osmotic relates to the osmotic pressure of that solution.  A solution of sucrose that is 320 mM is 320 milliosmolar, which is approximately iso-osmotic for humans.  Going back to the 154 mM NaCl, that will be 154 mM Na and 154 mM Cl or about 308 milliosmolar.  Very similar to the 320 milliosmolar for the sucrose.

Answer 4

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Answer 5

Yeah, essentially, tonicity is more an issue of salt concentration, whereas, strictly speaking, the term isosmotic refers to osmotic pressure gradients.