Introductory Biomechanics: From Cells to Organisms

Citation

Ethier, C. R., & Simmons, C. A. (2007). Introductory Biomechanics: From Cells to Organisms. Cambridge University Press.

Chapter Summary

The book has ten chapters and one appendix in roughly 500 pages. According to the preface, every chapter starts with a review of the relevant biology and then identifies and describes the essential mechanical aspects of the problem. Chapter 2 is by far the longest, at about 100 pages.

Chapter 1: Introduction

Defines bioengineering as the application of engineering principles to biological systems and biomechanics as the study of how physical forces interact with living systems. It argues that biomechanics matters for growth, development, tissue remodelling and some diseases, using the example that bone cells add or remove bone in response to mechanical stress and strain.

Chapter 2: Cellular biomechanics

The longest chapter. It is limited to eukaryotic cells and begins by reviewing cellular architecture, including the membranes and the organelles, before going on to the mechanics of the cell. Later chapters refer back to its section on the extracellular matrix.

Chapter 3: Hemodynamics

Treats blood flow and the forces that produce it, mostly viewing blood as a passive carrier of physiologically important substances. It begins with blood rheology, defined as how materials deform or flow in response to applied force, and with the concept of stress.

Chapter 4: The circulatory system

Looks at the heart and blood vessels from an engineering viewpoint, as a branching network of tubes served by two pulsatile pumps in series. It starts with the anatomy of the vasculature and the division into pulmonary and systemic circulations, and emphasises how the components operate and work together to deliver blood.

Chapter 5: The interstitium

A short chapter (about ten pages) on the space around the capillaries, made up of cells embedded in the extracellular matrix. It examines interstitial fluid flow and why flow resistance depends on matrix composition, cell density and packing.

Chapter 6: Ocular biomechanics

Describes the eye as a pressurised, thick-walled shell with fluid production and drainage, and shows the role of mechanics in accommodation and in disorders such as glaucoma, macular degeneration, myopia and presbyopia. It starts with ocular anatomy.

Chapter 7: The respiratory system

Begins with gross anatomy, the branching conducting airways and the acinus where gas exchange occurs, and then turns to the mechanics of breathing.

Chapter 8: Muscles and movement

Introduces the three muscle types and then concentrates on skeletal muscle, classified by how muscle produces ATP (aerobic and anaerobic). It provides the muscle and bone mechanics on which the locomotion analysis of Chapter 10 relies.

Chapter 9: Skeletal biomechanics

Covers the skeletal connective tissues (bone, cartilage, ligaments and tendons), beginning with the functions, structure and biomechanical behaviour of bone.

Chapter 10: Terrestrial locomotion

Analyses walking and running descriptively and quantitatively, and also treats jumping, for which a standing jump is divided into push-off and airborne phases and analysed through the motion of the centre of gravity.

Appendix: The electrocardiogram

A short appendix (about nine pages) on the ECG, introduced as a reference signal for pulsatile flow, pressure and arterial pulsation in the vascular tree, with an account of the electrical activity of cardiac muscle cells.

Key Concepts

Cells and fluids (Chapters 1–5)

• Mechanobiology: the idea that cells and tissues respond to mechanical stress and strain.
• Blood rheology: how blood deforms and flows under stress.
• Circulation as a network and pumps: arteries, veins and the pulsatile heart treated as a branching tube system with pumps.
• Interstitial flow resistance: how tissue structure governs fluid movement in the interstitium.

Organ systems (Chapters 6–7)

• Ocular pressure and accommodation: the mechanical function of the eye and how it relates to disease.
• Mechanics of breathing: airway branching and the mechanics of the lungs.

Movement (Chapters 8–10)

• Skeletal muscle energetics: aerobic and anaerobic ATP production.
• Bone as a mechanical tissue: structure and load-bearing behaviour.
• Locomotion analysis: jumping, walking and running described through the motion of the centre of gravity.

Critical Analysis

Strengths

• Biology is taught from scratch. The preface states that no prior knowledge of biology, anatomy or physiology is assumed, and every chapter begins with the relevant background. This lets readers from mechanical or chemical engineering and the physical sciences begin straight away.
• A single viewpoint across scales. The chapters run from single cells through blood, vessels, tissue and organs to whole-body locomotion, so one consistent mechanical treatment links them. The authors describe the approach as reducing a biological system to its essential elements, applying the laws of mechanics and tying the result back to biological function.
• Clarity noted by a reviewer. James E. Moore Jr. of Texas A&M, quoted on the publisher's page, describes the presentation as clear and straightforward, based on a long-standing course taught to non-bioengineers, and the illustrations as of excellent quality.
• Written for a course. The authors developed the book from an introductory biomechanics course at the University of Toronto because they could not find a text pitched at engineers; the publisher also mentions a large selection of problems and hundreds of references.

Limitations

• Selective by design. The preface says the book is not an extensive treatise on any branch but an introduction to a wide selection of topics. Several chapters follow a single organ system, and the chapter on the interstitium is only about ten pages.
• Mechanical prerequisites. The preface expects introductory dynamics, statics, fluid mechanics, thermodynamics and solid mechanics. Readers without these will need a separate preparation.
• Scope choices within chapters. Chapter 2 treats only eukaryotic cells and Chapter 8 concentrates on skeletal muscle only, so smooth and cardiac muscle are not developed. The book dates from 2007, so developments since then are not covered.

Where It Fits in the Course

Ethier and Simmons suit a first biomechanics course for engineering students. Özkaya and colleagues' Fundamentals of Biomechanics starts statics, dynamics and deformable-body mechanics from first principles for readers without an engineering background, and Knudson's Fundamentals of Biomechanics is an introduction to human movement with algebra-level calculation; either can precede this book for students who need to build the mechanics first. Peterson and Bronzino's edited volume covers more specialised topics, such as impact injury and inner-ear mechanics, in separately authored chapters and works better as a reference after a course like this one.

For readers who want rigorous continuum mechanics, Humphrey and O'Rourke's An Introduction to Biomechanics derives the governing equations of solids and fluids in full, and Fung's Biomechanics: Mechanical Properties of Living Tissues is the classic monograph on the constitutive behaviour of biological materials. Ethier and Simmons sit between a human-movement introduction and those continuum-mechanics treatments: a textbook that spans cells to organisms, with the mechanics applied to named physiological problems.

How to Use This Book

Read the preface first for the assumed background, then the Introduction (Chapter 1). A sensible core is Chapters 3 and 4 (blood and the circulation), Chapters 8 and 9 (muscle and the skeleton) and Chapter 10 (locomotion), which build on each other. Chapter 2 is large and can be used selectively: read the cell architecture review and then the mechanics sections that match the course. Chapters 5, 6 and 7 can be chosen to suit a course's emphasis, and the ECG appendix is a short companion to Chapters 3 and 4.

In each chapter, read the physiology introduction carefully before starting the analysis, as the authors intend the biology to frame the mechanics. Work the end-of-chapter problems, which the publisher describes as a large selection, and use the references for further reading. If the mechanics prerequisites are shaky, review statics, solid mechanics and fluid mechanics alongside the first chapters.