Tonicity

Physiology Ch 3 Types of Solutions.notebook

October 22, 2013

Types of Solutions that Cells May Be Found In

1) Hypotonic ­ Low [solutes] in ECF
2) Isotonic ­ solution equilibrium
3) Hypertonic ­ High [solutes] in ECF

Oct 19­9:29 AM

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Physiology Ch 3 Types of Solutions.notebook

October 22, 2013

Hypotonic ­ Low [solutes] in ECF

In this situation, water wants to move from the ECF to the inside of the cell since there is a lower [H2O] inside than out.

Particles (solutes) want to move out of the cell to the ECF since there is a lower [solute] outside the cell.

Hypertonic ­ High [solutes] in ECF

In this situation, water wants to move from the cell to the ECF since there is a lower [H2O] inside than out.

Particles (solutes) want to move into the cell from the ECF since there is a lower [solute] inside the cell.

Oct 19­9:36 AM

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Physiology Ch 3 Types of Solutions.notebook

October 22, 2013

Isotonic ­ solution equilibrium
There is no net movement of water or solutes in any one direction since the concentrations of both are equal on both sides of the membrane. Solutes and water still move in and out but they do so equally.

Ringer's Lactate solution, aka 0.9% sodium chloride (or KCl, CaCl2, etc) is isotonic to human tissue fluid. This solution is infused into the blood stream for a number of reasons:
* Irrigation of wounds
* Low blood volume (maintain blood pressure if blood is not available)
* Low electrolyes (dehydration)
* Maintain a catheter (IV line) for subsequent infusion of drugs Oct 19­9:44 AM

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