ANT202H5 Lecture Notes - Lecture 9: Vasodilation, Vasoconstriction, Hemoglobin
Document Summary
Adaptation to climate & altitude: physiological response to temperature stress, climate & morphological variation, hypoxia & high altitude adaptation. Physiological response to temperature stress: vasoconstriction: blood vessels narrow to reduce blood flow & heat loss, vasodilation: blood vessels open to increase blood flow & heat loss. "hunting" reaction: alternating vasocontraction & dilation in extremities exposed to cold. Only process that results in heat loss without heat gain. Coping with heat stress: vasodilation - increased transfer to internal heat to surface. Climate & morphological variation: body size & proportions. Important for regulation of internal body temperature: relationship between body size & shape with latitude. Mammals & birds: bergmann & allen"s rules. Bergmann"s rule: heat loss is a function of surface area, heat production is function of volume (i. e. body mass) Increased mass allows for greater heat retention & reduced heat loss. Linear body loses heat faster than compact body. Body size tends to be greater in populations living in cold climates.
