Heat in humans.

- Hypothermia in humans. (Temp constant core body despite variations in the ambient temperature) - Core temperature: contents of the head, chest and abdominal cavities. Fairly constant at 37 ° C surface temperature: + contact parts outside (skin and muscle). Ranges varying ambient temperature - Most of the heat is produced in deep body regions. Skin and subcutaneous tissue (especially fat) are thermal insulators. - Leather highly vascularized continuous flow venous plexus which can vary from almost 0 to 30% of GC Total. - Cutaneous blood flow leads high core body heat to the skin, whereas its decrease the reduced, thereby regulating the transfer of heat to the outside. The heat transfer between the body and the environment takes place through the skin surface by following mechanisms (table): radiation, conduction, convection and evaporation. Radiation: is the transfer of heat by infrared electromagnetic waves between the skin and the objects that surround it. Profit / Loss of heat by radiation + · skin - cold objects in the environment. Typical heat loss by radiation. In very hot media (eg. Summer and sun exposure), more than the human body, the body heat gain by radiation. The naked human body in a room at normal temperature removes 60% of the total heat loss by radiation. The color of the skin and clothes with which we cover affects the reflectivity of waves. The light color reflects more radiation than the dark color, reducing heat transfer by radiation. Driving: the transfer from molecule to molecule heat between solids liquids and gases; but most of all solids and liquids. Dependent mechanism of conductivity of the substance and temperature differences between the contact points. This mechanism takes real importance to immerse the body in the water. Equivalent to 5% of the total heat loss by the body under normal conditions.