Water in organism

Water in organism is divided into:


 * Free water – used to dissolve substances.


 * Hydration water - bounded to hydrophilic colloids.
 * Molecules of free and hydration water are constantly exchanged and in balance.

A person can go without water for 6-8 days, then he loses more than 11% of water from muscle or fat tissue and die.
 * Oxidising water – is formed during the burning of fats, proteins,...

Water metabolism
Water metabolism in the body is very closely linked to Na⁺ metabolism. The ability of the organism to store water and divide it into the appropriate compartments is determined by the amount of particles dissolved in it, i.e. the so-called osmolality.
 * Children have the content of water in the body higher (70−80%), and the proportion of ICT and ECT is also different (newborn has the volume of ECT even higher than ICT).
 * Failure in water metabolism are failures in osmoregulation. Normal plasma osmolality ranges from 275 to 295 mmol/kg. When it rises above the value of 278 mmol/kg, the secretion of antidiuretic hormone (ADH) begins. A further gradual increase in ADH secretion occurs as plasma osmolality increases – the maximum is reached at a value of 298 mmol/l. A further pathological increase in osmolality no longer leads to a further increase in ADH secretion. Another stimulus for ADH secretion is a 10-20% drop in circulating volume or a 5% drop in blood pressure. Anxiety, pain, some drugs (opiates, barbiturates, also chlorpropamide, acetaminophen) can have a similar effect.

Related articles

 * Dehydration
 * Physical and chemical properties of water
 * Water metabolism disorders
 * Perspiratio insensibilis

Source

 * With the permission of the autor adaptated from https://uloz.to/!CM6zAi6z/biofot-doc