A system of exercise, such as weight lifting, in which muscle tension is kept constant as the body works against its own, or an external, weight. The term also describes fluids, such as intravenous fluids or drinks, with the same osmotic pressure (see osmosis) as the blood. (See also isometric.)
Having the same salinity as body fluids. You can make a quart of water isotonic by adding a slightly rounded measuring teaspoon of table salt to a quart of water.
A term applied to solutions which have the same power of di?usion as one another. An isotonic solution used in medicine is one which can be mixed with body ?uids without causing any disturbance. An isotonic saline solution for injection into the blood, so that it may possess the same osmotic pressure (see OSMOSIS) as the blood SERUM, is one of 0·9 per cent strength – that is, containing 9 grams of sodium chloride to 1 litre of water. This is also known as normal or physiological salt solution. An isotonic solution of bicarbonate of soda for injection into the blood is one of 1·35 per cent strength in water. An isotonic solution of glucose for injection into the blood is one of 5 per cent strength in water.
Solutions which are weaker, or stronger, than the ?uids of the body with which they are intended to be mixed are known as hypotonic and hypertonic, respectively.
adj. 1. describing solutions that have the same osmotic pressure. See osmosis. 2. describing muscles that have equal *tonicity.
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