Thermal neutral zone
Encyclopedia
A thermal neutral zone (TNZ) is essentially an endotherm
's temperature tolerance range. Within the TNZ the basal rate
of heat production is in equilibrium with the rate of heat loss to the external environment. The endotherm does not have to use large amounts of energy to control its temperature within the thermal neutral zone
, the organism adjusts to the temperatures within the zone through different responses requiring little energy. It can show postural changes where it changes its body shape or moves and exposes different areas to the sun/shade, and through radiation, convection and conduction, heat exchange
occurs. Vasomotor responses allow control of the flow of blood between the periphery and the core to control heat loss from the surface of the body. Lastly, the organism can show insulation adjustments; a common example being “goosebumps” in humans where hair follicle
s are raised by pilomotor muscles, also shown in animals’ pelage and plumage. This allows heat to be trapped between hairs. Below the thermal neutral zone there is the zone of LCT (lower critical temperature) and above there is the zone of UCT (upper critical temperature). The organism reaches the LCT when the Ta (ambient temp.) decreases. When an organism reaches this stage the metabolic rate
increases significantly and thermogenesis increases the Tb (body temp.) If the Ta continues to decrease far below the LCT hypothermia occurs. When the Ta reaches too far out of the UCT the rate heat gain and heat production become higher than the rate of heat dissipation (heat loss through evaporative cooling), resulting in hyperthermia.
Warm-blooded
The term warm-blooded is a colloquial term to describe animal species which have a relatively higher blood temperature, and maintain thermal homeostasis primarily through internal metabolic processes...
's temperature tolerance range. Within the TNZ the basal rate
Basal rate
In biology, basal rate is the rate of continuous supply of some chemical or process. In the case of diabetes mellitus, it is a low rate of continuous insulin supply needed for such purposes as controlling cellular glucose and amino acid uptake....
of heat production is in equilibrium with the rate of heat loss to the external environment. The endotherm does not have to use large amounts of energy to control its temperature within the thermal neutral zone
Neutral zone
Neutral zone may refer to:In sports:* Neutral zone , the region between offensive and defensive sides prior to the snap of the ball on a scrimmage play* Neutral zone , zone between the blue lines in ice hockey...
, the organism adjusts to the temperatures within the zone through different responses requiring little energy. It can show postural changes where it changes its body shape or moves and exposes different areas to the sun/shade, and through radiation, convection and conduction, heat exchange
Heat exchange
Heat exchange may refer to:*Heat transfer, an area of engineering concerned with the transfer of thermal energy *Heat exchanger, a device built for heat transfer from one medium to another...
occurs. Vasomotor responses allow control of the flow of blood between the periphery and the core to control heat loss from the surface of the body. Lastly, the organism can show insulation adjustments; a common example being “goosebumps” in humans where hair follicle
Hair follicle
A hair follicle is a skin organ that produces hair. Hair production occurs in phases, including a growth phase , and cessation phase , and a rest phase . Stem cells are principally responsible for the production of hair....
s are raised by pilomotor muscles, also shown in animals’ pelage and plumage. This allows heat to be trapped between hairs. Below the thermal neutral zone there is the zone of LCT (lower critical temperature) and above there is the zone of UCT (upper critical temperature). The organism reaches the LCT when the Ta (ambient temp.) decreases. When an organism reaches this stage the metabolic rate
Metabolism
Metabolism is the set of chemical reactions that happen in the cells of living organisms to sustain life. These processes allow organisms to grow and reproduce, maintain their structures, and respond to their environments. Metabolism is usually divided into two categories...
increases significantly and thermogenesis increases the Tb (body temp.) If the Ta continues to decrease far below the LCT hypothermia occurs. When the Ta reaches too far out of the UCT the rate heat gain and heat production become higher than the rate of heat dissipation (heat loss through evaporative cooling), resulting in hyperthermia.