Temperature Regulation in Vertebrates

Vertebrates moderate the stresses associated with varying temperatures through subdivisions of the nervous system that sense skin and deep body temperatures and compare these temperatures with a neuronally repre­ sented ref erence. Resultant output responses characteristical ly involve sys­ tems that subserve or compete with other physiological functions, thereby establishing a strong interdependence between regulations of body tempera­ ture and of cardiovascular, respiratory, energetic, ionic, and osmotic vari­ ables. The precisely adjusted effector outputs have been carefully docu­ mented (13, 42) and characterized by a number qf models (11) relating thermal input and output functions. When the participating brain struc­ tures are closely investigated, however, it is apparent that the precision of the total thermoregulatory system involves a complex overlay of neuronal networks evolved at different times