Evaporation is a part of thermoregulation that maintains a constant body temperature in warm-blooded animals. The evaporation process is also known as the evaporation process and is triggered by decreased sympathetic nervous system tone in hot conditions. Increased evaporation is a predisposition also known as hyperhidrosis.
What is evaporation?
Evaporation maintains human body temperature despite high ambient temperatures. Evaporation occurs as part of thermoregulation. Thermoregulation is the term used to describe all the processes by which the body of a warm-blooded animal maintains a constant body temperature at the level that provides the ideal working temperature for bodily processes such as blood circulation, despite fluctuating ambient temperatures. This requires a permanent exchange of heat with the environment. This heat exchange takes place through various body mechanisms. In addition to evaporation, the body’s own mechanisms of heat exchange include convection, conduction and radiation. Conduction is the exchange of heat through direct contact. Convection is the exchange of heat through an exchange medium such as air. Radiation in medicine is heat radiation in the form of electromagnetic waves, and evaporation is heat loss through evaporation processes. Liquids are thickened in this process by removing water from them through a vacuum.
Function and task
Evaporation maintains human body temperature despite high ambient temperatures. Thus, heat loss through evaporation cools the body. When overheating occurs as a result of high ambient temperatures, the thermoregulatory center in the hypothalamus lowers the tone of the sympathetic nervous system. This lowering is the first step of thermoregulation and requires permanent temperature control by peripheral and visceral thermoreceptors. These are the free nerve endings of the sensitive neurons located in the skin and mucous membranes. They measure external and internal temperatures and transmit their signals centrally through neuronal convergences, which are summed in the first neuron and travel along the tractus spinothalamicus. Along this path, they reach the thalamus and are switched to the second neuron. The second neuron terminates with its projection fibers in the area of the hypothalamus. Thus, the hypothalamus, as the central regulatory center of body temperature, receives permanent information inputs. On the basis of the temperature data, it compares them and, if necessary, responds with regulatory processes to keep the body temperature constant. Heat thus causes the hypothalamus to lower the tone of the sympathetic nervous system. This lowering of tone triggers regulatory responses. One response to the tonal decrease is peripheral vasodilation. The second response mechanism is increased sweat secretion. Peripheral vasodilation corresponds to vasodilation in peripheral blood vessels. This results in improved blood flow to the extremities. The heat exchange surface is thus increased and greater heat loss can thus take place by convection. Sweat secretion takes place through the sympathetically cholinergically innervated sweat glands, also known as glandulae sudoriferae. They increase their secretion by increasing sympathetic tone. Evaporation of sweat produces the so-called evaporative cooling and the skin is cooled. This process corresponds to evaporation.
Diseases and ailments
Increased evaporation accompanies a variety of clinical pictures. Usually, these clinical pictures are tied to fever, which is lowered by the body through evaporation. However, evaporation itself can also take on pathological proportions. It then does not occur as a symptom of a primary disease, but is itself present as a primary disease. One of the best known diseases in this context is hyperhidrosis. This phenomenon corresponds to a genetic predisposition to pronounced sweating, which is usually locally limited to a certain area of the body. Especially the arms, armpits, feet or hands are often affected by hyperhidrosis. In principle, however, hyperhidrosis can also affect the entire body. In most cases, the underlying cause of such a phenomenon is an overfunction of the local sweat glands. What stimulates the sweat glands to overfunction often remains unclear.Stress and psychological problems can play just as big a role in the clinical picture as hyperthyroidism. Above all, stress and psychologically induced hyperfunctions are a vicious circle, as the sweating usually makes the affected person feel even more stress and thus has a negative effect on the psyche. Dyshidrosis is also a well-known condition that is related to evaporation in the broadest sense. In this condition, small and fluid-filled vesicles form, causing significant itching. Dyshidrosis often accompanies hyperhidrosis, although medical science is as yet uncertain about the connection. Since various medications also affect thermoregulation and evaporation, some hyperhidrosis and the dyshidrosis that occurs with it are drug-related and thus cannot be directly called a disease, but are rather a side effect. A change in the hypothalamus or sympathetic nervous system can also cause problems with evaporation. Such changes can be, for example, tumors in these brain regions. Similarly, diseases of the central nervous system are possible causes of changes in these brain regions. For example, if the tone of the sympathetic nervous system remains permanently at a low level due to dysregulation, excessive sweating may occur despite cold temperatures. The consequences of such a phenomenon are manifold and make it difficult for the body to maintain body temperature. Thus, the phenomenon can have a negative impact on all temperature-related body processes.
