Physics in Biology and Medicine

352 Pages·2008·5.464 MB·English

by  Paul Davidovits

Third Edition
Physics in Biology and Medicine
Complementary Science Series
ACADEMIC PRESS
2008—To be published
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Third Edition
Physics in Biology
and Medicine
Paul Davidovits
AMSTERDAM•BOSTON•HEIDELBERG•LONDON
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SANFRANCISCO•SYDNEY•TOKYO
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ISBN-13:978-0-12-369411-9(pbk.:alk.paper)1.Biophysics.2.Medicalphysics.I.Title.
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Contents
Preface xiii
Abbreviations xvii
1 Static Forces 1
1.1 EquilibriumandStability................................ 2
1.2 EquilibriumConsiderationsfortheHumanBody........... 3
1.3 StabilityoftheHumanBodyundertheActionofan
ExternalForce.......................................... 4
1.4 SkeletalMuscles........................................ 7
1.5 Levers................................................. 9
1.6 TheElbow............................................. 11
1.7 TheHip................................................ 15
1.7.1 Limping........................................ 17
1.8 TheBack.............................................. 17
1.9 StandingTip-ToeonOneFoot........................... 19
1.10 DynamicAspectsofPosture............................. 19
Exercises .............................................. 21
2 Friction 23
2.1 StandingatanIncline................................... 25
2.2 FrictionattheHipJoint................................. 26
v
vi Contents
2.3 SpineFinofaCatfish................................... 27
Exercises .............................................. 29
3 Translational Motion 30
3.1 VerticalJump........................................... 32
3.2 EffectofGravityontheVerticalJump .................... 35
3.3 RunningHighJump..................................... 36
3.4 RangeofaProjectile.................................... 37
3.5 StandingBroadJump ................................... 37
3.6 RunningBroadJump(LongJump)....................... 39
3.7 MotionthroughAir..................................... 40
3.8 EnergyConsumedinPhysicalActivity.................... 42
Exercises .............................................. 43
4 Angular Motion 45
4.1 ForcesonaCurvedPath................................. 45
4.2 ARunneronaCurvedTrack............................. 47
4.3 Pendulum.............................................. 48
4.4 Walking ............................................... 50
4.5 PhysicalPendulum...................................... 51
4.6 SpeedofWalkingandRunning........................... 52
4.7 EnergyExpendedinRunning............................ 54
4.8 AlternatePerspectivesonWalkingAndRunning........... 56
4.9 CarryingLoads......................................... 58
Exercises .............................................. 59
5 Elasticity and Strength of Materials 61
5.1 LongitudinalStretchandCompression.................... 61
5.2 ASpring............................................... 62
5.3 BoneFracture: EnergyConsiderations.................... 64
5.4 ImpulsiveForces ....................................... 66
5.5 FractureDuetoaFall: ImpulsiveForceConsiderations..... 67
5.6 Airbags: InflatingCollisionProtectionDevices............ 68
5.7 WhiplashInjury........................................ 69
5.8 FallingfromGreatHeight............................... 70
5.9 OsteoarthritisandExercise .............................. 70
Exercises .............................................. 71
Contents vii
6 Insect Flight 73
6.1 HoveringFlight......................................... 73
6.2 InsectWingMuscles.................................... 75
6.3 PowerRequiredforHovering............................ 76
6.4 KineticEnergyofWingsinFlight........................ 78
6.5 ElasticityofWings...................................... 79
Exercises .............................................. 80
7 Fluids 82
7.1 ForceandPressureinaFluid............................. 82
7.2 Pascal’sPrinciple....................................... 83
7.3 HydrostaticSkeleton.................................... 84
7.4 Archimedes’Principle................................... 87
7.5 PowerRequiredtoRemainAfloat........................ 87
7.6 BuoyancyofFish....................................... 88
7.7 SurfaceTension ........................................ 89
7.8 SoilWater ............................................. 92
7.9 InsectLocomotiononWater............................. 93
7.10 ContractionofMuscles.................................. 95
7.11 Surfactants............................................. 97
Exercises .............................................. 99
8 The Motion of Fluids 101
8.1 Bernoulli’sEquation.................................... 101
8.2 ViscosityandPoiseuille’sLaw........................... 103
8.3 TurbulentFlow......................................... 104
8.4 CirculationoftheBlood................................. 105
8.5 BloodPressure......................................... 107
8.6 ControlofBloodFlow.................................. 109
8.7 EnergeticsofBloodFlow................................ 110
8.8 TurbulenceintheBlood................................. 110
8.9 ArteriosclerosisandBloodFlow.......................... 111
8.10 PowerProducedbytheHeart............................ 112
8.11 MeasurementofBloodPressure.......................... 113
Exercises .............................................. 114
viii Contents
9 Heat and Kinetic Theory 116
9.1 HeatandHotness....................................... 116
9.2 KineticTheoryofMatter................................ 116
9.3 Definitions............................................. 119
9.3.1 UnitofHeat..................................... 119
9.3.2 SpecificHeat.................................... 119
9.3.3 LatentHeats..................................... 120
9.4 TransferofHeat........................................ 120
9.4.1 Conduction ..................................... 120
9.4.2 Convection...................................... 121
9.4.3 Radiation....................................... 122
9.4.4 Diffusion....................................... 123
9.5 TransportofMoleculesbyDiffusion...................... 126
9.6 DiffusionthroughMembranes............................ 128
9.7 TheRespiratorySystem................................. 129
9.8 SurfactantsandBreathing................................ 132
9.9 DiffusionandContactLenses............................ 133
Exercises .............................................. 133
10 Thermodynamics 135
10.1 FirstLawofThermodynamics ........................... 135
10.2 SecondLawofThermodynamics......................... 137
10.3 DifferencebetweenHeatandOtherFormsof
Energy................................................. 138
10.4 ThermodynamicsofLivingSystems...................... 140
10.5 InformationandtheSecondLaw......................... 143
Exercises .............................................. 144
11 Heat and Life 145
11.1 EnergyRequirementsofPeople.......................... 146
11.2 EnergyfromFood...................................... 147
11.3 RegulationofBodyTemperature......................... 149
11.4 ControlofSkinTemperature............................. 151
11.5 Convection............................................. 151
11.6 Radiation.............................................. 153
11.7 RadiativeHeatingbytheSun ............................ 153
Contents ix
11.8 Evaporation............................................ 155
11.9 ResistancetoCold...................................... 156
11.10 HeatandSoil........................................... 158
Exercises .............................................. 159
12 Waves and Sound 162
12.1 PropertiesofSound..................................... 162
12.2 SomePropertiesofWaves............................... 165
12.2.1 ReflectionandRefraction.......................... 165
12.2.2 Interference..................................... 166
12.2.3 Diffraction...................................... 168
12.3 HearingandtheEar..................................... 168
12.3.1 PerformanceoftheEar............................ 171
12.3.2 FrequencyandPitch.............................. 172
12.3.3 IntensityandLoudness............................ 173
12.4 BatsandEchoes........................................ 175
12.5 SoundsProducedbyAnimals............................ 176
12.6 AcousticTraps......................................... 176
12.7 ClinicalUsesofSound.................................. 177
12.8 UltrasonicWaves....................................... 177
Exercises .............................................. 178
13 Electricity 180
13.1 TheNervousSystem.................................... 180
13.1.1 TheNeuron..................................... 181
13.1.2 ElectricalPotentialsintheAxon.................... 183
13.1.3 ActionPotential.................................. 184
13.1.4 AxonasanElectricCable.......................... 186
13.1.5 PropagationoftheActionPotential.................. 188
13.1.6 AnAnalysisoftheAxonCircuit.................... 190
13.1.7 SynapticTransmission ............................ 193
13.1.8 ActionPotentialsinMuscles ....................... 194
13.1.9 SurfacePotentials................................ 194
13.2 ElectricityinPlants..................................... 196
13.3 ElectricityintheBone................................... 196