d49b36f6_BiologyMad_A_Level_Biology__Response_to_low_temperature
[Effector] Smooth muscles in peripheral arterioles in the skin. [Response to high temperature] Muscles relax causing vasodilation. More heat is carried from the core to the surface, where it is lost by convection and radiation. Skin turns red. [Response to low temperature] 
Muscles contract causing vasoconstriction. Less heat is carried from the core to the surface of the body, maintaining core temperature. Extremities can turn blue and feel cold and can even be damaged (frostbite).
BiologyMad A-Level Biology
Response to low temperature