Principles and Models of Biological Transport

Citation

Friedman, M. H. (2008). Principles and Models of Biological Transport (2nd ed.). Springer.

Chapter Summary

The second edition has eleven chapters. In the preface the author explains that the book, like its first edition, deals with the mass transport processes of living systems, with a focus on the normal behaviour of eukaryotic cells and the organisms they make up in their normal physiological environment. It therefore differs from a conventional transport text: it does not start from the engineering principles of mass transport and look for biological applications, but begins with the biological processes and then develops the models and analytical tools needed to describe them. Many processes must still be described phenomenologically, with methods such as nonequilibrium thermodynamics, and simple electrical analogues with few parameters can be more useful than detailed theory.

Chapter 1: Equilibrium Thermodynamics

The book opens with equilibrium thermodynamics, before any transport mechanism is named in a chapter title.

Chapter 2: Free Diffusion

Free diffusion is the first transport mechanism to get its own chapter, and it comes before the chapters on facilitated diffusion and active transport.

Chapter 3: The Cell

A chapter on the cell, placed between the general chapters on thermodynamics and diffusion and the chapters on transport across membranes.

Chapters 4–5: Facilitated Diffusion: Channels and Carriers; Active Transport

Chapter 4 treats facilitated diffusion through channels and carriers, and Chapter 5 active transport. These are the chapters in which the molecular mechanisms of transport across membranes are modelled.

Chapters 6–7: Nonequilibrium Thermodynamics; Models of Transport Across Cell Membranes

Chapter 6 develops nonequilibrium thermodynamics, one of the phenomenological methods named in the preface, and Chapter 7 builds models of transport across cell membranes.

Chapter 8: Regulation and Feedback

A chapter on regulation and feedback, coming after the models of membrane transport and before the chapters on specific systems.

Chapters 9–10: Excitable Cells; Epithelial Transport

Two chapters that put the mechanisms of the earlier chapters to work in specific biological systems: excitable cells and epithelia.

Chapter 11: Gas Transport

The final chapter turns from ions and solutes to the transport of gases.

Key Concepts

Chapters 1–3: Equilibrium Thermodynamics; Free Diffusion; The Cell

• Equilibrium thermodynamics: the starting framework for transport.
• Free diffusion: transport without mediation by membrane proteins.
• The cell: the biological setting for transport.

Chapters 4–8: Mechanisms, thermodynamics and models

• Channels and carriers: facilitated diffusion.
• Active transport: transport driven by an energy source.
• Nonequilibrium thermodynamics: a phenomenological framework for coupled transport.
• Regulation and feedback: control of transport processes.

Chapters 9–11: Systems

• Excitable cells: the subject of Chapter 9.
• Epithelial transport: movement across epithelia.
• Gas transport: the movement of gases in the body.

Critical Analysis

Strengths

• Biology drives the method. The author states that the biology determines the choice of analysis tools, so models are consistently presented in the context of real biological systems and analysis and biology are interwoven.
• A distinctive scope. The book concentrates on normal eukaryotic cells and organisms in their physiological environment, which sets it apart from transport texts organised around engineering principles.
• Practical modelling choices. The preface stresses phenomenological tools, including nonequilibrium thermodynamics, and simple electrical analogues, which suit processes that cannot be derived from first principles.
• Support for learners. The second edition adds figures, references and end-of-chapter problems, and, according to its listing, a companion website for classroom use.

Limitations

• Narrow by design. The focus on mass transport in normal physiology means that momentum and heat transport, which other biotransport books treat alongside it, are not the subject here.
• Thermodynamics first. The book opens with equilibrium thermodynamics, then free diffusion, so readers short of physical chemistry will meet demanding material early.
• Dated by publication. The edition appeared in 2008.

Where It Fits in the Course

This is the specialist treatment of molecular transport across membranes and tissues in the biotransport course. Ronald Fournier's Basic Transport Phenomena in Biomedical Engineering applies fluid flow, mass transfer and thermodynamics from chemical engineering to physiological systems, and Roselli and Diller's Biotransport: Principles and Applications treats momentum, heat and mass transport with one consistent method. Bird, Stewart, Lightfoot and Klingenberg's Introductory Transport Phenomena is a first course in transport in general, and Rubenstein, Yin and Frame's Biofluid Mechanics concentrates on flow in the circulation. Truskey, Yuan and Katz's Transport Phenomena in Biological Systems is a quantitative bridge between transport theory and physiology covering flow, diffusion, reaction and electrokinetics.

Because the book begins from biology instead of from engineering transport theory, it is not a replacement for a first course in transport phenomena. Read Friedman after one of the general transport texts, when the interest turns to how cells and epithelia move ions and molecules, and use it beside Truskey, Yuan and Katz for the membrane and cell-level material.

How to Use This Book

Per the listing, the book is meant for advanced undergraduates and graduate students in biomedical engineering, physiology or biophysics, and for engineers and quantitatively minded biologists who want to interpret transport experiments. A background in thermodynamics, calculus and differential equations is a sensible preparation, and the preface is worth reading first because it explains why the book is arranged as it is.

A practical plan:

• Core: Chapters 1 to 5 in order: thermodynamics, free diffusion, the cell, then channels, carriers and pumps.
• Next: Chapters 6 and 7, which supply the nonequilibrium and model-building framework.
• By interest: Chapter 8 on regulation and feedback, then whichever of Chapters 9 (excitable cells), 10 (epithelia) and 11 (gases) matches the course.

Do the end-of-chapter problems, since the stated purpose is to help readers interpret transport experiments and to predict behaviour from transport data. Read each mechanism chapter with the matching system chapter in mind, for example channels and carriers (Chapter 4) before excitable cells (Chapter 9), so that the models are seen in use.