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Thermogenesis is the process of heat production in organisms.It occurs in all warm-blooded animals, and also in a few species of thermogenic plants such as the Eastern skunk cabbage, the Voodoo lily (Sauromatum venosum), and the giant water lilies of the genus Victoria.
Both processes consume energy, however high-intensity shivering uses glucose as a fuel source and low-intensity tends to use fats. This is a primary reason why animals store up food in the winter. [citation needed] Brown adipocytes are also capable of producing heat via a process called non-shivering thermogenesis. In this process ...
In addition to heat produced by shivering muscle, brown adipose tissue produces heat by non-shivering thermogenesis. The therapeutic targeting of brown fat for the treatment of human obesity is an active research field. [10] [11]
The UCP1, or thermogenin, gene likely arose in an ancestor of modern vertebrates, but did not initially allow for our vertebrate ancestor to use non-shivering thermogenesis for warmth. It wasn't until heat generation was adaptively selected for in placental mammal descendants of this common ancestor that UCP1 evolved its current function in ...
Norepinephrine increases thermogenesis in brown adipose tissue, and muscle contraction through shivering raises the metabolic rate. [ 85 ] If these measures are insufficient to make the blood temperature in the brain match the new set point in the hypothalamus, the brain orchestrates heat effector mechanisms via the autonomic nervous system or ...
The second is non-shivering, which occurs in brown adipose tissue. [19] Population studies have shown that the San tribe of Southern Africa and the Sandawe of Eastern Africa have reduced shivering thermogenesis in the cold, and poor cold-induced vasodilation in fingers and toes compared to that of Caucasians. [5]
Additionally, almost all eutherian mammals (with the only known exception being swine) have brown adipose tissue whose mitochondria are capable of non-shivering thermogenesis. [8] This process involves the direct dissipation of the mitochondrial gradient as heat via an uncoupling protein , thereby "uncoupling" the gradient from its usual ...
The metabolic rate is increased, initially by non-shivering thermogenesis, [37] followed by shivering thermogenesis if the earlier reactions are insufficient to correct the hypothermia.