What Are Isotonic Solutions?

An isotonic solution refers to a solution having an amount equivalent to that of plasma. Such as 0.9% NaCl solution and 5% glucose solution. A solution that is less than the amount of plasma penetration is called a hypotonic solution, and cells can edema or even rupture in a hypotonic solution. A solution that is higher than the amount of plasma penetration is called a hypertonic solution, and cells can dehydrate and shrink in a hypertonic solution.

Isotonic solution

Isotonic solution refers to the amount of penetration equivalent to that of plasma

Experimental observation, normal plasma

Isotonic solutions are equal in tension and isotonic solutions are equal in osmotic pressure.

Isotonicity: A solution equal to the osmotic pressure of plasma, which belongs to the concept of physical chemistry.

Isotonicity: A solution with an osmotic pressure equal to the tension of the red blood cell membrane, a biological concept.

If the molecule cannot penetrate the cell membrane, isotonic and isotonic are equal.

5% glucose sodium chloride is an isotonic solution.

Hypotonicity or hyperosmosis or isotonicity is based on the concentration of solution and plasma,

A solution equal to the osmotic pressure of plasma is called an isotonic solution. Such as 5% glucose solution or 0.9% sodium chloride solution.

A solution with a lower osmotic pressure than plasma is called a hypotonic solution. Such as distilled water.

A solution with a higher osmotic pressure than plasma is called a hypertonic solution. Such as 10% glucose solution or 50% glucose solution.

The so-called isotonic fluid means that the fluid used has the same tension as the red blood cells. The so-called isotonic fluid is similar to plasma osmotic pressure. From a physiological point of view, red blood cells in the isotonic fluid neither swell or shrink, maintaining their original shape. From the perspective of physical and chemical concepts, try to imagine that a certain solution is separated from plasma with a semi-permeable membrane. If the osmotic pressure of the solutions on both sides of the semi-permeable membrane is equal, this solution is an isotonic solution.

Under normal circumstances, the osmotic pressure of extracellular fluid and intracellular fluid is similar. The balance of osmotic pressure inside and outside the cell is dependent on the movement of water between inside and outside the cell. When the extracellular fluid has a higher osmotic pressure than the intracellular fluid, water flows from the inside of the cell to the outside, and vice versa. Whether it is an electrolyte or a non-electrolyte solution, after entering the body, the drug particles cannot enter or rarely enter the red blood cells, causing the relative decrease in the osmotic pressure of the red blood cells. The water flows out and causes the cells to shrink. ; If the drug particles enter the red blood cells too much, the intracellular osmotic pressure will increase, and some of the water will be sucked into the red blood cells, causing them to swell. This solution is hypotonic. When the volume changes, it can be called isotonic fluid.

Clinically, people are accustomed to express the form of water and salt disorders as changes in osmotic pressure. For example, when the loss of water is greater than the loss of salt, which causes the blood sodium concentration to be higher than 150mmol / L, the plasma osmotic pressure is> 310mOsm / L, which is called hypertonic dehydration. Osmotic pressure <290 mmol / L. It is called hypotonic dehydration; when the blood sodium concentration is between 135 ~ 150mmol / L, it is called isotonic dehydration.