Introduction
Role of the skin in protecting against dehydration
One of the main functions of the epidermis is to create a barrier between the internal environment and the external environment, protecting us from dehydration.
Our body is mainly composed of water (55-65% in relation to age), that is about 42 kg in a 70 kg man in good physical shape.
For the survival of the individual, given the vital importance of body water, it is essential that the water content is kept constant. The skin is therefore very important, as it opposes an excessive dispersion of water in the environment.
Despite this, a fair amount of body water is eliminated daily through the skin. Such a phenomenon is called numb or perspiration perspiratio insensibilis, numb because we don't realize it.
The loss of body water through the skin increases dramatically in the event of a burn. In the damaged area, water loss is considerable and, if it is extensive enough, it compromises the vital functions of the organism.
Perspiratio Insensibilis
What it is and General characteristics
With the term "perspiratio insensibilis"the physiological loss of water through the skin or respiratory tract is commonly indicated.
Skin water loss should not be confused with sweat, since, while perspiratio is a passive step, sweating is an active glandular secretion, which requires a certain energy expenditure.
Respiratory losses, on the other hand, are linked to the abundant water vapor content of the exhaled air.
In basal conditions, water losses related to perspiratio insensibilis vary according to the surface and body mass, as well as according to the temperature of the external environment. Taking as a reference an individual weighing about 70 kg for a height of about 1.70 meters, the loss of water through insensitive perspiration it can vary from about 400 ml at a temperature of 22 ° C up to almost 700 ml with temperatures that increase up to 30 ° C.
Even if we do not realize it, the elimination of water is therefore substantial, one more reason to emphasize, once again, the "importance of" adequate fluid intake with the diet.
It must also be considered that this loss can increase, for example, during sporting activity. An organism engaged in physical effort eliminates more water, because the breathing rate increases and above all because the loss of water through the skin is much higher. L "evaporation of water" in fact removes heat from the body, participating in the thermoregulatory mechanisms, with the aim of maintaining internal homeothermy.
Continue reading with:
Corneocytes - Odland's Bodies and Natural Hydration FactorOr, go back to the first part:
The skin: Differentiation of keratinocytes
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