Friday, July 1, 2011

Physiology is the link between the basic sciences and medicine

When Russ Hobbie and I need to cite a general physiology reference in the 4th edition of Intermediate Physics for Medicine and Biology, we often choose the Textbook of Medical Physiology. The book was originally written by Arthur Guyton, but in the most recent editions the lead author is John Hall. We cite the book in several places: 1) In Chapter 1, we reproduce one of Guyton’s figures of the human circulatory system (we reference the 8th edition of the Textbook of Medical Physiology, 1991), 2) We cite Guyton in Chapter 5 when discussing osmotic pressure and when analyzing countercurrent transport, 3) When discussing nerve synapses and neurotransmitters we cite the 10th edition (2000) on which Hall is also first author, 4) In our chapter on feedback loops (Chapter 10) we reproduce a figure showing how alveolar ventilation responds to exercise from the 9th edition (1995, Guyton sole author), and 5) In Chapter 11 on the method of least squares we base Homework Problem 15 on data from Guyton’s textbook regarding the secretion of cortisol by the adrenal gland.

When I was a graduate student at Vanderbilt University, I decided to sit in on the physiology and biochemistry classes that the medical students took. The physiology class was based on Guyton’s book (likely the 6th or 7th edition). I took the class seriously, but since I had little formal coursework in biology (only one introductory class as an undergraduate at the University of Kansas, plus a high school course), and because I didn’t get as much out of the lectures as I should have, my main accomplishment was reading the Textbook of Medical Physiology, cover to cover. Unfortunately, my copy of the book has been lost (probably loaned out to someone who forgot to return it). It is a pity, because I have fond memories of that book, and all the physiology I learned while reading it.

The 12th edition of the Textbook of Medical Physiology (2010) was published after the 4th edition of Intermediate Physics for Medicine and Biology went to press. Hall and Guyton’s preface states
“The first edition of the Textbook of Medical Physiology was written by Arthur C. Guyton almost 55 years ago. Unlike most major medical textbooks, which often have 20 or more authors, the first eight editions of the Textbook of Medical Physiology were written entirely by Dr. Guyton, with each new edition arriving on schedule for nearly 40 years. The Textbook of Medical Physiology, first published in 1956, quickly became the best-selling medical physiology textbook in the world. Dr. Guyton had a gift for communicating complex ideas in a clear and interesting manner that made studying physiology fun. He wrote the book to help students learn physiology, not to impress his professional colleagues.

I worked closely with Dr. Guyton for almost 30 years and had the privilege of writing parts of the 9th and 10th editions. After Dr. Guyton's tragic death in an automobile accident in 2003, I assumed responsibility for completing the 11th edition.

For the 12th edition of the Textbook of Medical Physiology, I have the same goal as for previous editions—to explain, in language easily understood by students, how the different cells, tissues, and organs of the human body work together to maintain life.

This task has been challenging and fun because our rapidly increasing knowledge of physiology continues to unravel new mysteries of body functions. Advances in molecular and cellular physiology have made it possible to explain many physiology principles in the terminology of molecular and physical sciences rather than in merely a series of separate and unexplained biological phenomena.

The Textbook of Medical Physiology, however, is not a reference book that attempts to provide a compendium of the most recent advances in physiology. This is a book that continues the tradition of being written for students. It focuses on the basic principles of physiology needed to begin a career in the health care professions, such as medicine, dentistry and nursing, as well as graduate studies in the biological and health sciences. It should also be useful to physicians and health care professionals who wish to review the basic principles needed for understanding the pathophysiology of human disease.

I have attempted to maintain the same unified organization of the text that has been useful to students in the past and to ensure that the book is comprehensive enough that students will continue to use it during their professional careers.

My hope is that this textbook conveys the majesty of the human body and its many functions and that it stimulates students to study physiology throughout their careers. Physiology is the link between the basic sciences and medicine. The great beauty of physiology is that it integrates the individual functions of all the body's different cells, tissues, and organs into a functional whole, the human body. Indeed, the human body is much more than the sum of its parts, and life relies upon this total function, not just on the function of individual body parts in isolation from the others…”
If you are a physicist studying from Intermediate Physics for Medicine and Biology with little background in biology and medicine, you will need to find a good general source of information about physiology. The Guyton and Hall Textbook of Medical Physiology is a good choice. Another book Russ and I cite a lot is Textbook of Physiology by Patton, Fuchs, Hille, Scher and Steiner. However, I cannot find an edition more recent than 1989, so it would not be a good choice for getting up-to-date information.

Arthur Guyton (1919-2003) was a famous physiologist, known for his research on the circulatory system. An obituary published in the Physiologist says
“Arthur Guyton’s research contributions, which include more than 600 papers and 40 books, are legendary and place him among the greatest figures in the history of cardiovascular physiology. His research covered virtually all areas of cardiovascular regulation and led to many seminal concepts that are now an integral part of our understanding of cardiovascular disorders such as hypertension, heart failure, and edema. It is difficult to discuss cardiovascular regulation without including his concepts of cardiac output and venous return, negative interstitial fluid pressure and regulation of tissue fluid volume and edema, regulation of tissue blood flow and whole body blood flow autoregulation, renal-pressure natriuresis, and long-term blood pressure regulation.

Perhaps his most important scientific contribution, however, was a unique quantitative approach to cardiovascular regulation through the application of principles of engineering and systems analysis. He had an extremely analytical mind and an uncanny ability to integrate bits and pieces of information, not only from his own research but also from others, into a quantitative conceptual framework. He built analog computers and pioneered the application of large-scale systems analyses to modeling the cardiovascular system before digital computers were available. With the advent of digital computers, his cardiovascular models expanded dramatically in the 1960’s and 70’s to include the kidneys and body fluids, hormones, autonomic nervous system, as well as cardiac and circulatory functions. He provided the first comprehensive systems analysis of blood pressure regulation and used this same quantitative approach in all areas of his research, leading to new insights that are now part of the everyday vocabulary of cardiovascular researchers.

Many of his concepts were revolutionary and were initially met with skepticism, and even ridicule, when they were first presented. When he first presented his mathematical model of cardiovascular function at the Council for High Blood Pressure Research meeting in 1968, the responses of some of the hypertension experts, recorded at the end of the article, reflected a tone of disbelief and even sarcasm. Guyton’s systems analysis had predicted a dominant role for the renal pressure natriuresis mechanism in long-term blood pressure regulation, a concept that seemed heretical to most investigators at that time. One of the leading figures in hypertension research commented “I realize that it is an impertinence to question a computer and systems analysis, but the answers they have given to Guyton seem authoritarian and revolutionary.” Guyton’s concepts were authoritarian and revolutionary, but after 35 years of experimental studies by investigators around the world, they have also proved to be very powerful in explaining diverse physiological and clinical observations. His far-reaching concepts will continue to be the foundation for generations of cardiovascular physiologists."
If you are interested in the interface between physics and physiology, you will find the Guyton and Hall Textbook of Medical Physiology to be a valuable resource.

2 comments:

  1. Have you visited Google Body?

    http://bodybrowser.googlelabs.com/

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