BIOB34H3 Chapter Notes - Chapter 10: Thermogenin, Vasomotor, Hyperthermia
Document Summary
The bmr of mammals, when compared to the smr of poikilotherms at the same temperature is still 4 to. Metabolic intensity was stepped up when homeothermy was evolved. The difference in metabolic rates shows even more when temperatures are reduced or elevated. Therefore mammals and birds need to acquire food at much higher rates. Pilomotor (mammals) and ptilomotor (birds) responses adjust hair and feather posture to modulate insulation. Vasomotor responses alter blood flow to skin and other superficial body areas to modulate insulation. Dilate at warm temperatures and constrict at cold temperatures. Postural responses alter amount of body surface in contact with ambient conditions. Below tnz: a higher weight specific mr means an increased rate of weight specific weight loss, and therefore a higher weight specific cost of thermoregulation. Metabolic heat production is increased via thermogenic processes: shivering. Unsynchronized, contraction and relaxing of random muscles. Antagonistic muscles contract and cause quivering: non-shivering thermogenesis.
