882 



Index 



Porifera, cholinergic systems in muscles 

 in, 611 

 oxygen supply of, 211 

 oxygen withdrawal by, 251 

 See also Sponges. 

 Porphyropsin, phylogenetic origin of, 412 

 Porpoise, respiration in, 260 

 Posture, nervous control of, 831, 832 

 Potassium, efiFect on visceral muscles, 606 

 in synaptic transmission, 795 

 ions, efifects on hearts, 562, 563 

 in sea water and body fluids, 78 

 in tissues and body fluids, 76 

 ratios of concentration, 82 

 nerve conduction and, 780 

 Potential, action, nerve, 777 

 end-plate, 588 

 ganglionic, 797 

 synaptic, 797 

 Praying mantis, brain in, 820 

 Precipitins, immune, 107 

 Pregnanediol, 747 

 Presbyopia, 395 



Pressure, blood, measurement and regula- 

 tion of, 534. See also Blood pressure. 

 hydrostatic, effects on various gel sys- 

 tems, 635 

 responses to, 509 

 osmotic. See Osmotic pressure. 

 oxygen. See Oxygen tension. 

 partial, of gases in dry air, 210 

 Prey, mechanisms for seizing, 146 

 Primates, cortical localization in, 838 

 Prochordates, proteinases in, 162 

 Progesterone, structure of, 743 

 Progestins, 746 

 Prolactin, 748 



Prohne, structural formula, 119 

 Proprioceptors, 503 

 Protanopia, 437 

 Proteases, classification of, 157 

 Protein(s), blood, pigments as, 334 

 degradation of, compared with purine 

 breakdown, 202 

 products, enzymes of, 201 

 types of, 187 

 digestion of, 157-168 

 electrophoretic separation of, 103 

 immunological specificity of, 105 

 in blood, 103, 104 



size of, 105 

 in hemoglobin, 297 

 metabolism of, distribution of excretory 



products, 190-200 

 oxygen consumption in utilization of, 



237 

 sedimentation of, 105 

 specificity, 103-111 

 Proteinases, characteristics of, 160-163 

 distribution of, 163 



Proteinases. See also Protease. 

 Prothrombin, vitamin K and, 133 

 Protocerebnun, 818 

 Protopterus annectens, lungs of, 219 

 Protozoa, adaptation to marine, fresh-water 

 and parasitic hfe, 38-46 

 anaerobiosis in, 273 

 avenues of water entrance in, 43 

 bioliuninescence in, 661 

 carbon and nitrogen requirements in, 



113 

 carbon requirements in, 114 

 chemoreception in, 448 

 conditional responses in, 843 

 contractile vacuoles of, 38 

 efficiency of, 46 

 function of, 40 

 mechanism of filling, 44 

 essential elements for, 94 

 exopeptidases in, 166 

 fat digestion in, 177 

 membrane permeability in, 39 

 nitrogen excretion in, 191, 192 

 osmotic adjustment in, 10 

 osmotic concentration of cytoplasm of, 



39 

 oxygen supply of, 211 

 pH of digestive organs, 152 

 pH of food vacuoles in, 155 

 photoreceptors in, 383 

 proteinases of, 160 

 site of digestion in, 150 

 thiamine requirements, 123 

 trichocysts in, 654 

 Pseudocoelom, 531 

 Pseudopodia, as feeding mechanism, 145 



types of, 630, 631 

 Psychic stimuli, efiFect on color change, 



684 

 Pterines, excretion of, 190 

 Pteroylglutamic acid, 128 

 Puffer fish, oxygen withdrawal by, 252, 

 253 

 respiration in, 261 

 Pugettia, oxygen consumption and body 



weight of, 228 

 Pupation in insects, 735 

 Purines, breakdown of, 190 



excretion of in various animals, 192-196 

 in diet, 130 



metabolism of, compared with protein 

 breakdown, 202 

 distribution of enzymes and products 



of, 203 

 evolutionary trends in, 205 

 products, excretion of, 189 

 Purkinje tissue, 546 

 Pyridoxal, 127 

 Pyridoxamine, 127 

 Pyridoxine, 127 



