Conduction is a type of heat transport and one of four mechanisms by which the body exchanges heat with the environment as part of thermoregulation. Underlying conduction are Brownian motions. They allow heat in the insulated body to move from higher-temperature to lower-temperature regions.
What is conduction?
Conduction is a type of heat transport. It allows the body to be in heat exchange with the environment as part of thermoregulation. According to the law of conservation of energy, energy is a quantity of conservation. Accordingly, the total energy of an isolated system does not change, but at most transforms into different forms of energy. The law of conservation of energy also applies to heat transport in the isolated system of the human body. Heat conduction in the human organism is also called conduction and corresponds to the heat flow in a solid that takes place in the context of temperature differences. According to the second law of thermodynamics, heat always flows in the direction of the lower temperature. Unlike convection, conduction does not require a flow of material for thermal transport. Heat transport therefore takes place in the context of conduction without material transport via tissue. Skin contact with a material also establishes thermal conduction. The amount of heat transported during conduction depends on thermal conductivities and temperature differences. Conduction is also known as heat diffusion and is one of four heat transport mechanisms in the human body.
Function and purpose
The four physical mechanisms for heat transport in the human body are radiation, convection, evaporation, and conduction. Evaporation is heat loss through sweating as part of thermoregulation. Radiation refers to the infrared portion of thermal radiation and is thus not bound to matter. Conduction refers to heat transport in a body at rest and convection is heat transport by means of a moving medium. Biology distinguishes between an internal and an external heat transport. The external heat transport is the permanent heat exchange that takes place with the environment through the skin. The internal heat transport means the transport of body heat starting from the place of heat origin to the body surface. Convection and conduction play a role in the internal heat flow. In conduction, heat transport takes place via the Brownian molecular motion of a substance. Brownian motion is known as the jerky irregular heat movements of particles in a viscous medium. The square of the distance covered increases on average in proportion to the absolute temperature and the time interval. It is inversely proportional to the particle radius and viscosity. This principle underlies all biological diffusion. In heat transfer by Brownian molecular motion, there is an equalization of the heat gradient as the particles move toward the lower temperature regions. In this process, the physical properties of the substance determined the magnitude of the resulting heat flux. In physiological tissues, the water balance is the conducting factor. The thermal conductivity is determined by the thermal conductivity coefficient. Like all other heat exchange mechanisms, conduction causes permanent heat loss and passive heating at the same time. The human organism depends on a constant body temperature for the ideal functioning of all metabolic processes. The constant maintenance of the temperature takes place both by constant heat production in the sense of the thermogenesis, and by the isolation opposite the environment and the ability for the body temperature lowering. Body heat results from energy conversion in two systems. Muscles and metabolism are involved. Muscles turn chemical energy into kinetic energy. Heat transport of these energies occurs primarily by forced convection through the blood.
Diseases and ailments
Impaired thermoregulation can cause numerous organ dysfunctions in the human body, making it a systemic disease. Since conduction is one of several causes of heat loss, it may be related to hypothermia. Hypothermia is hypothermia that occurs after exposure to cold. In this case, the production of heat in the body is less than the release of heat for a certain period of time.Hypothermia can be fatal in extreme cases. Local cold effects cause frostbite, which permanently damages the tissue. Hypothermia plays a role, for example, in connection with injured mountain athletes and is automatically considered in intensive care units if the patient’s medical history and a suitable clinical picture are available. Medicine distinguishes between different stages of hypothermia. Mild hypothermia is present at a body temperature between 32 and 35 degrees Celsius. Usually, muscle tremors, tachycardia, tachypnea and vasoconstriction or apathy and ataxia can be observed at these temperatures. In moderate hypothermia, the temperature has dropped to 28 degrees Celsius. In addition to clouding of consciousness, bradycardia, and dilated pupils, patients present with a decreased gag reflex, hyporeflexia, or cold-deprivation. Severe hypothermia is said to occur at temperatures below 28 degrees Celsius, as it can cause circulatory arrest, decreased brain activity, fixed pupils, and cardiac arrhythmias or respiratory arrest, in addition to unconsciousness. Hypothermia can occur after accidents in water, in mountains and caves or after staying in considerably cold environment. Various diseases, sedentary behaviors due to neurological defects, extreme physical exertion or shock can also trigger hypothermia. The same applies to excessive alcohol consumption and the associated blood vessel dilation in the skin. Patients suffering from the rare Shapiro syndrome also suffer from fundamental and recurrent defects in thermoregulation. As a thermoregulatory center, their hypothalamus is affected by dysfunction.
