Peripheral centers of body temperature control – non-central thermoregulation
In addition to the thermoregulation center in the preoptic region of the hypothalamus, there are smaller centers in the spinal cord. These spinal centers register the temperature of a series of flowing blood and may have some effect on local heat production and heat transfer.
In case of violation of the integrity of the spinal cord, the patient does not produce sweat and lacks the ability to maintain normal body temperature at a very high external temperature. In animals, there may be a tremor in the muscles below the level of the intersection of the spinal cord if this part of the brain is cooled locally. However, such animals do not develop fever during infection and the ability to maintain body temperature within normal limits sharply decreases with changes in ambient temperature, which is not extreme for healthy animals.
These lower located thermoregulation centers can be compared with potential heart rate drivers, located below the sinoatrial (CA) node. Many areas of the heart, such as the atrioventricular (AV) node, the atrioventricular bundle, and even the ventricular wall, have the ability to function as pacemakers and cause heart contractions, although with a lower frequency than the CA node.
During normal operation of the CA node, potential pacemakers do not show their activity. Similarly, the activity of the spinal thermoregulatory centers is normally suppressed by the midbrain, and they begin to function independently only if the higher centers work or if there is damage localized below the midbrain. Under these conditions, spinal centers, like lower-placed cardiac pacemakers, work well enough to support life under normal conditions, but they can effectively respond to stress.
When the spine is cut in dogs and rabbits, thermoregulation may partially recover due to the spinal centers. The fact that such a recovery is not observed in sick people can be explained by the fact that patients in general are well cared for and not exposed to chronic or repeated cold effects.