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General Physiology
Oxygen Test 2
oxygen regulation | steady rate of O2 consumption reagardless of environmental levels -often requires increased breathing rate |
oxygen conformity | rate of O2 consumption falls with depleting environmental levels |
regulation abilities | evolved according to habitat in which a species lives -fish in low O2 tend to have broader range of O2 regulation |
O2 deprivation | can tissues to become hypoxic or anoxic (low or absence of O2) |
O2 deprivation due to | low concentration of O2 in environment -altitude, hypoxic water behaviors that prevent respiration (diving) |
O2 deprivation acute responses | -Switch to anaerobic catabolism -Metabolic depression – regulated reduction in the ATP needs of whole organism or specific tissue --By rate-limiting enzymes or reduced mitochondria |
acclimation compensation | tendency for a trait to return to original function even though a new environmental pressure persists -Change in blood characteristics due to hypoxic conditions Lower O2 levels Increase oxygen transporters |
adaptation to hypoxia Animal anaerobes | Some animals survive whole-body anoxia for long periods; remain behaviorally alert |
animal anaerobes biochemical specializations | All tissues make ATP by anaerobic fermentation → lactic acid -During anoxia Lactic acid ethanol and CO2 -Allows excretion of waste product -Prevents acidification |
Locomotion | Small- bodied species tend to require greater weight-specific MRs to move at any particular speed |
fish swims | -MR increases as a J-shaped power function with speed -Drag created by water increases as swim speed increases |
walking/running | Typically linear relationship between speed and MR -Regardless of taxa |
flying | U shape relationship between speed and MR |
factors of minimal cost of locomotion | body size- Large-bodied organism cover greater distance with lower weight-specific cost |
Type of locomotion influences cost | Cost of swimming is lower in fish -Likely due to morphological streaming Cost of swimming is typically higher at the surface than underwater because: -Swimming not primary mode -Swimming at surface is more costly due to hydrodynamics |
minimal cost of transport | relative to body size depends primarily on the type of locomotion rather than phylogeny and locomotor mechanism (how they move) -Interspecific comparisons statistically show animals fall on same allometric line |
Maximal rate of oxygen consumption | Relevance: -Determines the peak rate at which an individual can synthesize ATP during aerobic respiration -Provides a standard by which to determine strenuousness of an aerobic activity |
Aerobic scope | difference between VO2 max and resting rate |
Aerobic expansibility | ratio of VO2max over resting rate |
Factors affecting VO2max | Peak VO2max in poikilotherms is approximately the same as BMR of a similar sized homeotherm -Homeotherms can make aTP faster →longer sustained exercise |
factors affecting VO2 max | body size- Within a phyletic group, small species tend to have higher VO2max per gram genetics & experience increase with endurance training -gene expression (more mito, more enzymes) -increase ability to pump blood |
symmorphosis | Variation in VO2max among individuals/species may be due to -Suggests that all physiological processes have approximately equal limitations; have adapted together |
example of symmorphosis | Pronghorns, fastest sustained runners -large lungs, high rates of blood circulation, high abundance of mitochondria |
acute responses -diving | brain lacks ability to sufficiently make ATP anaerobically Short dives use stored O2 Long dives divide O2 forcing tissues to catabolize anaerobically coma Some species can survive anoxia in all tissues pond turtles |