Control of body temperature

Thermoregulation

It is the control of body temperature. It involves both coordination systems - nervous & endocrine

All mammals generate heat and have ways to retain it within their bodies. They also have physiological methods to balance heat gain, retention of body heat and heat loss so that they maintain a constant body temperature. This means they are not dependent on absorbing heat from their surroundings and can be actvie throughout the day and seasons. Other animals rely on external sources of heat and so are often inactive when it is cold.

• heat generated by mammals is released during respiration
• much of the heat is produced by liver cells that have a huge requirement for energy
  • the heat they produce is absorbed by the blood flowing through the liver and distributed around the rest of the body
• the hypothalamus in the brain is the central control for the body temp; it's the body thermostat
  • this region of the brain receives a constant input of sensory information about the temperature of the blood and temperature of the surroundings
  • it has thermoreceptor cells that continually monitor temperature of blood flowing through it
  • the temperature it monitors is the core temperature - the temperature inside the body that remains very close to the set point (37 degrees C in humans)
  • this temperature flactuates but is kept within narrow limits by the hypothalamus

The hypothalamus receives information about temperature from other sources aswell like the skin which contains receptors that monitor changes in skin temperature.

The skin receptors give an 'early warning' about possible change in core temperature since the skin temperature is the first to change if there's a change in surrounding temperature. The hypothalamus upon detection by skin receptors then send impulses that activate the following physiological responses;

• Vasoconstriction - muscles…