In the materialistic view we regard living organisms as enormously complex collections of matter, capable of powering certain chemical reactions with free energy4 from external sources. These reactions include synthesizing the structural elements of the organism itself, as well as generating new autonomous organisms of the same pattern, i.e., reproduction. Self-replication is the key distinction between living organisms and inanimate matter.
Our mental model of a living organism is therefore a kind of machine. In this sense, living organisms are the most complicated machines we know of, and therefore in many ways not especially amenable to the methods of physics.
Author(s): Julian V. Noble
Year: 2003
Language: English
Pages: 146
1. Review of Newtonian Physics
2. Dimensional Analysis and Scaling
3. Musculoskeletal system and locomotion
4. Fluid Mechanics and Living Organisms
5. Bioenergetics
6. Some Ideas from Thermodynamics
7. Diffusive Processes and Brownian Motion
8. Properties of Water
9. Excitable Cells
10. Sound, hearing and the human voice
11. The Human Visual System
12. Effects of radiation on Living Organisms
13. Physics of Diagnostic Methods
A. Mathematical Review
DETAILED CONTENTS:
Preface i
Review of Newtonian Physics 1
Linear Momentum 1
Work and energy 1
Power 2
Extended bodies 2
Center of mass 2
Rotation 3
Moment of inertia 5
Applications 8
Firearms 8
Automobile collisions 9
Dimensional analysis
and scaling laws 13
Dimensional analysis 13
Surface waves in deep water 14
Allometric scaling 15
Strength to weight ratio 15
Structural strength 16
Terminal velocity 17
How high can you jump? 17
Basal metabolism 18
Lifetimes 19
Brain size 19
Musculoskeletal system 23
Skeletons of land verterbrates 23
Muscle 23
Mechanical (dis)advantage 24
Virtual work 24
Hill’s Law 25
Basics of locomotion 26
Walking 26
Scaling arguments 28
Timing 29
Walking power 30
Transition to running 32
Running power 33
Other considerations 34
Maximum speed 34
Animals that cannot run 34
Fluid mechanics and
living organisms 37
Euler’s equation 37
Conservation of fluid 38
The Navier-Stokes equation 39
Reynolds’ number 40
Steady Flow in pipes 40
Impedance 42
Pulsatile flow in arteries 42
Bioenergetics 45
Energy input to living organisms 45
Energy demand of organs 46
Heating and cooling 47
Appendix—Planck’s blackbody radiation law 49
Some ideas from thermodynamics 53
The First Law of Thermodynamics 53
Equation of state 54
Thermodynamic relations 54
Heat engines and Carnot efficiency 56
The Second Law of Thermodynamics 59
Statistical Mechanics 59
Boyle’s Law 59
Maxwell-Boltzmann distribution 60
Applications of Maxwell-Boltzmann
distributions 62
Liquid-vapor equilibrium 62
Reaction rates 62
Dissolved gases 63
The bends 64
Diffusive processes and Brownian motion 65
Random walk model of diffusion 65
The mean and variance of the position 66
Stochastic differential equation 67
Thermal “force” and osmotic pressure 69
Brownian motion and diffusion 70
Diffusion across a synapse 70
How a cell eats 70
The properties of water 73
Static properties 73
Solvent properties 73
Solubility of H2O in H2O 74
Viscosity 74
Specific heat 75
Heat of vaporization 76
Vapor pressure 77
Excitable cells 79
Electrocardiography 79
Neurons 82
Sensory cells 84
Membrane potentials 84
Energetics of muscle tissue 85
Sound, hearing and the human voice 87
Sound propagation in gases 87
Hearing and the ear 90
Response to sound 92
Frequency response of the ear 93
Spatial discrimination of sounds 93
The human voice 95
The human visual system 99
Simple lenses 99
Problems with lenses 101
Problems with vision 102
Light → nerve impulses 103
Vision and the brain 105
Effects of radiation on living organisms 107
Background 107
Effects of penetrating radiations 108
Passage of radiation through matter 110
Attenuation of radiation in matter 113
Radiation exposure and dosage units 114
Effects of radiation exposure 115
Appendix 118
Physics of diagnostic methods 119
Auscultation 119
Blood pressure 120
Ultrasound imaging 121
Magnetic resonance imaging 122
X-rays and computerized tomography 125
Radioactive tracers 12
Mathematical review 127
Review of Trigonometry 127
Areas and Volumes 128
Integration 128
Differentiation 129
The fundamental theorem of calculus 130
Functions of several variables 130
Ordinary differential equations 131
Vectors 134
Vector analysis 135
Basic ideas of probability theory 137
