Physiological Mechanisms of Endotherms to Maintain Body Temperature:
Component of Body Responses if Core Body Responses if Core
Involved: Temperature is Too Body Temperature is
High: Too Low:
Sweat Glands in Skin Secrete more sweat. Secrete less sweat,
Lungs, Mouth & Nose Panting increases Animal does not pant.
evaporation from moist
surfaces.
Hairs on Skin Hairs lie flat. Hairs are raised to trap
a layer of insulating air.
Arterioles Leading to Vasodilation allows more Vasoconstriction
Capillaries in Skin blood into capillaries reduces blood flow
near the skin’s surface. through capillaries
near the skin’s surface.
Liver Cells Metabolic rate reduced – Metabolic rate is
less heat generated from increased – more heat
exergonic reactions. generated from
exergonic reactions.
Skeletal Muscles No spontaneous Spontaneous
contractions (shivering). contractions generate
heat through
respiration.
Behavioural Mechanisms to Maintain Body Temperature:
Behaviour if Too Hot: Behaviour if Too Cold:
Move into shade or burrow. Move into sunlight.
Orientate body to decrease SA exposed Orientate body to increase SA
to Sun. exposed to Sun.
Remain inactive and spread out the Move about to generate heat in
limbs to increase SA. muscles – curl up if extreme cold to
reduce SA.
Component of Body Responses if Core Body Responses if Core
Involved: Temperature is Too Body Temperature is
High: Too Low:
Sweat Glands in Skin Secrete more sweat. Secrete less sweat,
Lungs, Mouth & Nose Panting increases Animal does not pant.
evaporation from moist
surfaces.
Hairs on Skin Hairs lie flat. Hairs are raised to trap
a layer of insulating air.
Arterioles Leading to Vasodilation allows more Vasoconstriction
Capillaries in Skin blood into capillaries reduces blood flow
near the skin’s surface. through capillaries
near the skin’s surface.
Liver Cells Metabolic rate reduced – Metabolic rate is
less heat generated from increased – more heat
exergonic reactions. generated from
exergonic reactions.
Skeletal Muscles No spontaneous Spontaneous
contractions (shivering). contractions generate
heat through
respiration.
Behavioural Mechanisms to Maintain Body Temperature:
Behaviour if Too Hot: Behaviour if Too Cold:
Move into shade or burrow. Move into sunlight.
Orientate body to decrease SA exposed Orientate body to increase SA
to Sun. exposed to Sun.
Remain inactive and spread out the Move about to generate heat in
limbs to increase SA. muscles – curl up if extreme cold to
reduce SA.
