CONTENTS IX 



(e) The heart and aortic arches of modern reptiles 112 



(f ) The mammalian double circulation 1 1 8 



(g) Structural and physiological changes in the 



mammalian heart and circulation at birth 119 



9. Cellular Respiration 125 



(a) The cytochrome system 126 



(b) Energy relationships 128 



(c) The supply of ATP 130 



(d) Lactic acid and exercise 132 



10. Conclusions 136 



Further Reading 140 



Index 143 



