ANT202H5 Lecture Notes - Lecture 17: Vasodilation, Vasoconstriction, Coping With
Document Summary
Adaptation to climate and altitude nov 24th, 2016: physiological response to temperature stress. Vasoconstruction blood vessels narrow to reduce blood flow and heat loss. Vasodilation - blood vessels open to increase blood flow and heat loss. Hunting reaction alternating vasoconstriction and dilation in extremities exposed to cold. Radiation (60%) heat flow through electromagnetic radiation. Convection (15%) heat flow through our molecules. Conduction (3%) heat exchange through physical contact with other objects: * above three methods = gain heat. Evaporation (22%) heat loss through conversion of water to vapour. Only process where you lose heat without heat gain. Vasodilation increased transfer of internal heat to surface. More effective in dry vs humid conditions. Important for regulation of internal body temperature. Relationship between body size and shape with latitude. Increased mass allows for greater heat retention and reduced heat loss. Heat production: function of volume (i. e, body mass) Volume = same; surface area is increased.
