1 Terminology, the Standard Human, and Scaling ................ 1
1.1 Anatomical Terminology ................................. 1
1.2 Motion in the Human Machine ............................ 3
1.3 The Standard Human ..................................... 16
1.4 Scaling Relationships .................................. 22
1.4.1 Allometric Rules ................................ 22
1.4.2 Scaling in the Senses ........................... 25
1.5 Summary ................................................ 26
Problems .................................................... 26
2 Statics of the Body ......................................... 37
2.1 Review of Forces, Torques, and Equilibrium ............. 37
2.2 Statics: Motion in One Plane and Levers ................ 40
2.3 Statics in the Body .................................... 43
2.3.1 The Lower Arm ................................... 44
2.3.2 Hip Problems .................................... 49
2.3.3 Statics of Other Synovial Joints ................ 59
2.3.4 Lower Back Problems ............................. 66
2.3.5 Three-Force Rule ................................ 76
2.3.6 Multisegment Modeling ........................... 77
2.4 The Sense of Touch ..................................... 79
2.5 Diversion into the Units of Force and Pressure ......... 80
2.5.1 Force ........................................... 80
2.5.2 Pressure ........................................ 81
2.6 Summary ................................................ 82
Problems .................................................... 83
3 Motion ...................................................... 93
3.1 Kinematics and Musculature ............................. 93
3.2 Standing ............................................... 95
3.2.1 Stability ....................................... 95
3.2.2 Forces on the Feet ............................. 100
3.3 Walking ............................................... 102
3.3.1 Kinematics ..................................... 102
3.3.2 Muscular Action ................................ 104
3.3.3 Friction ....................................... 105
3.3.4 Energetics ..................................... 109
3.3.5 Review of Harmonic Motion, Pendulums,
and Moments of Inertia ......................... 113
3.3.6 Ballistic (or Pendulum) Model of Walking ....... 118
3.3.7 Inverted Pendulum Model ........................ 120
3.4 Running ............................................... 121
3.4.1 Kinematics ..................................... 122
3.4.2 Muscular Action ................................ 124
3.4.3 Energetics ..................................... 126
3.4.4 Bouncing Ball/Pogo Stick Model ................. 131
3.5 Jumping ............................................... 133
3.5.1 Vertical Jump .................................. 133
3.5.2 Pole Vault ..................................... 137
3.6 Throwing a Ball ....................................... 138
3.6.1 Throwing a Spinning Ball ....................... 148
3.6.2 Power Generated During a Throw ................. 150
3.7 Other Types of Motion ................................. 151
3.8 Collisions of the Human Body .......................... 153
3.8.1 Kinematics of a Collision ...................... 154
3.8.2 Consequences of Collisions ..................... 157
3.8.3 Hitting Balls .................................. 166
3.8.4 Running ........................................ 169
3.8.5 Jumping ........................................ 170
3.9 Sustained Acceleration ................................ 170
3.10 Physics of Sports .................................... 172
3.11 Summary .............................................. 172
Problems ................................................... 172
4 Mechanical Properties of the Body .......................... 193
4.1 Material Components of the Body ....................... 195
4.1.1 Bone ........................................... 197
4.1.2 Ligaments and Tendons .......................... 198
4.1.3 Cartilage ...................................... 199
4.2 Elastic Properties .................................... 201
4.2.1 Basic Stress-Strain Relationships .............. 201
4.2.2 Other Stress-Strain Relations .................. 203
4.2.3 Bone Shortening ................................ 205
4.2.4 Energy Storage in Elastic Media ................ 205
4.3 Time-Independent Deviations in Hookean Materials ...... 208
4.3.1 Non-Hookean Materials .......................... 217
4.4 Static Equilibrium of Deformable Bodies
(Advanced Topic) ...................................... 218
4.4.1 Bending of a Beam (or Bone) .................... 224
4.5 Time-Dependent Deviations from Elastic Behavior:
Viscoelasticity ....................................... 228
4.5.1 Perfect Spring ................................. 233
4.5.2 Perfect Dashpot ................................ 235
4.5.3 Simple Viscoelastic Models ..................... 236
4.6 Viscoelasticity in Bone ............................... 242
4.7 Bone Fractures ........................................ 244
4.7.1 Modes of Sudden Breaking of Bones .............. 245
4.7.2 Stress Fractures (Advanced Topic) .............. 252
4.8 Common Sports Injuries ................................ 256
4.9 Avoiding Fractures and Other Injuries:
Materials for Helmets ................................. 259
4.10 Summary .............................................. 261
Problems ................................................... 262
5 Muscles .................................................... 271
5.1 Skeletal Muscles in the Body .......................... 271
5.1.1 Types of Muscle Activity ....................... 275
5.2 The Structure of Muscles .............................. 276
5.3 Passive Muscles ....................................... 281
5.4 Activating Muscles: Macroscopic View .................. 281
5.4.1 Mechanical Model of the Active State
of Muscles ..................................... 284
5.5 The Effect of Exercise ................................ 290
5.5.1 Muscle Fatigue ................................. 291
5.6 Coordination of Muscles ............................... 292
5.7 Active/Tetanized Muscles: Microscopic View ............ 292
5.7.1 Total Muscle Tension ........................... 294
5.7.2 Everyday Proof of the Limited Range
of Useful Muscle Length ........................ 296
5.8 Hill Force-Velocity Curve ............................. 298
5.9 The Sliding Filament Model: Nanoscopic View ........... 305
5.10 Summary ............................................... 310
Problems ................................................... 310
6 Metabolism: Energy, Heat, Work, and Power
of the Body ................................................ 319
6.1 Conservation of Energy and Heat Flow .................. 319
6.2 Energy Content of Body Fuel ........................... 322
6.2.1 Metabolizable Energy and Energy Storage ........ 325
6.3 Energy Storage Molecules .............................. 329
6.3.1 How ATP is Produced and Used as an
Energy Source .................................. 329
6.3.2 How ATP is Actually Used by the Body ........... 331
6.4 Metabolic Rates ....................................... 338
6.4.1 Basal Metabolic Rate ........................... 338
6.4.2 Metabolic Rates during Common Activities ....... 344
6.4.3 Weight Gain and Loss ........................... 358
6.5 Loss of Body Heat ..................................... 361
6.5.1 Modes of Heat Loss ............................. 361
6.6 Body Temperature ...................................... 377
6.7 Summary ............................................... 384
Problems ................................................... 384
7 Fluid Pressure, Fluid Flow in the Body, and Motion
in Fluids .................................................. 405
7.1 Characteristic Pressures in the Body .................. 405
7.1.1 Definition and Units ........................... 405
7.1.2 Measuring Pressure ............................. 407
7.2 Basic Physics of Pressure and Flow of Fluids .......... 408
7.2.1 Law of Laplace ................................. 409
7.2.2 Fluids in Motion ............................... 411
7.2.3 Equation of Continuity ......................... 413
7.2.4 Bernoulli's Equation ........................... 413
7.2.5 Interactions among the Flow Parameters ......... 415
7.2.6 Viscous Flow and Poiseuille's Law .............. 415
7.3 Diffusion (Advanced Topic) ............................ 426
7.4 Pressure and Flow in the Body ......................... 428
7.5 Motion of Humans in Fluids ............................ 431
7.5.1 Swimming ....................................... 431
7.5.2 Human Flight ................................... 434
7.6 Summary ............................................... 436
Problems ................................................... 436
8 Cardiovascular System ...................................... 443
8.1 Overview of the Circulatory System and Cardiac Cycle .. 443
8.1.1 Circulation .................................... 443
8.1.2 Cardiac Cycle .................................. 446
8.1.3 Valves ......................................... 452
8.2 Physics of the Circulation System ..................... 454
8.2.1 Properties of Blood ............................ 454
8.2.2 Blood Pressure and Flow in Vessels ............. 455
8.2.3 Capillaries and Osmotic Pressure ............... 470
8.2.4 Blood Flow Rates and Speeds .................... 473
8.2.5 Consequences of Clogged Arteries ............... 482
8.2.6 Work Done by the Heart
and the Metabolic Needs of the Heart ........... 485
8.3 Strokes and Aneurysms ................................. 487
8.3.1 Arterial Bifurcations and Saccular Aneurysms ... 491
8.3.2 Stenosis and Ischemic Strokes .................. 494
8.3.3 Equation of Motion of Arteries and Aneurysms
during Pulsatile Flow (Advanced Topic) ......... 495
8.4 Modeling the Circulatory System and the Heart ......... 497
8.4.1 Model of the Heart ............................. 498
8.4.2 Model of the Overall Flow in the
Circulatory System ............................. 501
8.4.3 The Arterial Pulse ............................. 504
8.4.4 Windkessel Model ............................... 507
8.4.5 Modeling the Malfunctioning Heart .............. 509
8.5 Summary ............................................... 511
Problems ................................................... 511
9 Lungs and Breathing ........................................ 525
9.1 Structure of the Lungs ................................ 526
9.2 The Physics of the Alveoli ............................ 531
9.3 Physics of Breathing .................................. 534
9.4 Volume of the Lungs ................................... 537
9.5 Breathing Under Usual and Unusual Conditions .......... 539
9.5.1 Flow of Air During Breathing ................... 539
9.5.2 Mechanical Model of Breathing and
Model Parameters ............................... 541
9.5.3 Inspiration/Expiration Cycle ................... 541
9.5.4 Breathing with a Diseased Lung ................. 543
9.5.5 Breathing at Higher Elevations ................. 546
9.6 Work Needed to Breathe ................................ 547
9.7 Summary ............................................... 548
Problems ................................................... 548
10 Sound, Speech, and Hearing ................................. 555
10.1 The Physics of Sound Waves ............................ 555
10.1.1 The Speed and Properties of Sound Waves ........ 557
10.1.2 Intensity of Sound Waves ....................... 558
10.1.3 What Happens when Sound Travels
from One Medium to Another? .................... 565
10.1.4 Resonant Cavities .............................. 567
10.2 Speech Production ..................................... 571
10.2.1 Types of Sounds ................................ 571
10.2.2 Systems in Speech Production ................... 575
10.2.3 Parameters of the Human Voice .................. 589
10.2.4 The Energetics of Speaking ..................... 591
10.3 Hearing ............................................... 591
10.3.1 Auditory Sensitivity ........................... 593
10.3.2 Connections to Hearing Perception .............. 611
10.4 Other Vibrations in the Body .......................... 616
10.4.1 Cardiac and Other Sources of Sounds ............ 616
10.5 Summary ............................................... 619
Problems ................................................... 619
11 Light, Eyes, and Vision .................................... 629
11.1 Structure of the Eye .................................. 629
11.2 Focusing and Imaging with Lenses ...................... 636
11.2.1 Image Formation ................................ 636
11.2.2 Scientific Basis for Imaging ................... 638
11.2.3 Combinations of Lenses or Refractive Surfaces .. 643
11.3 Imaging and Detection by the Eye ...................... 650
11.3.1 Transmission of Light in the Eye ............... 650
11.3.2 The Eye as a Compound Lens ..................... 653
11.3.3 Accommodation .................................. 658
11.3.4 Field of View and Binocular Vision ............. 660
11.3.5 Adjustments of Light Levels .................... 660
11.3.6 Limitations to Visual Acuity ................... 663
11.3.7 Imperfect Human Vision ......................... 673
11.3.8 Correction of Vision by Eyeglasses,
Contact Lenses, and Other Means ................ 677
11.4 Types of Vision Impairment ............................ 686
11.5 Connections to Visual Perception ...................... 688
11.6 Vision in Other Animals ............................... 695
11.7 Summary ............................................... 698
Problems ................................................... 699
12 Electrical and Magnetic Properties ......................... 713
12.1 Review of Electrical Properties ....................... 714
12.2 Electrical Properties of Body Tissues ................. 718
12.2.1 Electrical Conduction through Blood
and Tissues .................................... 718
12.3 Nerve Conduction ...................................... 720
12.3.1 Cell Membranes and Ion Distributions ........... 722
12.3.2 Types of Cell Membrane Excitations ............. 730
12.3.3 Model of Electrical Conduction along an Axon ... 731
12.4 Ion Channels, Hair Cells, Balance, Taste, and Smell ... 743
12.5 Electrical Properties of the Heart .................... 746
12.6 Electrical Signals in the Brain ....................... 755
12.7 Effects of Electric Shock ............................. 756
12.8 Magnetic Properties ................................... 757
12.8.1 Magnetic Field from an Axon .................... 757
12.8.2 Magnetic Sense ................................. 758
12.9 Electromagnetic Waves ................................. 759
12.10 Summary .............................................. 759
Problems ................................................... 760
13 Feedback and Control ....................................... 767
13.1 Basics of Feedback and Control ........................ 768
13.1.1 Control Theory (Advanced Topic) ................ 770
13.2 Regulation of the Body ............................... 771
13.2.1 Regulation of Temperature ...................... 771
13.2.2 Control of Blood Pressure ...................... 777
13.2.3 Regulation During Exercise ..................... 778
13.3 Summary ............................................... 779
Problems ................................................... 779
Appendix A Symbols and Units .................................. 781
Appendix B Locator of Major Anatomical and
Anthropometric Information ......................... 787
Appendix C Differential Equations ............................. 789
C.l Simple First- and Second-Order
Differential Equations ........................ 789
C.2 Exponential Decay and Drag .................... 791
C.3 Harmonic Oscillator ........................... 793
C.4 Partial Differential Equations ................ 795
Appendix D Similar Model Systems .............................. 799
D.l Distributed vs. Lumped Models:
Electrical Analogs of Blood
Flow (Advanced Topic) ......................... 802
Appendix E Biophysics of the Human Body ..................... 805
Solutions ..................................................... 807
References .................................................... 815
Index ......................................................... 845
|
