2011 Respiratory Lecture
LungHumanCast is a macroscopic view of a plastic cast of the airways (yellow) the pulmonary arteries (red) and veins (blue) of a human lung
2011's lecture was presented by Professor Ewald Rudolf Weibel, Professor Emeritus of Anatomy Institute of Anatomy, University of Berne, Switzerland.
Professor Weibel presented his talk entitled 'What Makes a Good Lung? The Structural Basis of Pulmonary Gas Exchange.' on Wednesday 16 March 2011.
The lecture was chaired by Professor Peter Barnes and Professor Neil Pride presented the vote of thanks.
Biography
Weibel Ewald R. MD, DSc(hon), Dr.med.h.c. Professor Emeritus of Anatomy Institute of Anatomy, University of Berne, Switzerland.
Professor Ewald R. Weibel
Ewald R. Weibel, born in 1929, studied medicine at the University of Zurich, graduating as MD in 1955. He spent five postdoctoral years in the United States working in pathology at Yale University, in cardio-respiratory physiology at Columbia University, and in cell biology at The Rockefeller Institute. In 1963 he returned to Switzerland as Assistant Professor at the University of Zurich and became, in 1966, Professor and Chairman of the Institute of Anatomy at the University of Berne until his retirement in 1994, serving as Rector of the University of Berne in 1984-85. In his research he developed the concept and methods of morphometry in view of quantitative studies of structure-function relations in the lung and the entire respiratory system, the pathway for oxygen from lung to mitochondria and in humans as well as in mammals.
Among other honors he was awarded the Marcel-Benoist Prize, the Anders Retzius Gold Medal, the Medal of the American College of Chest Physicians, and the Purkinje Gold Medal. He received Honorary Doctorates from the Universities of Edinburgh and Geneva. He is Foreign Associate of the US National Academy of Sciences and member of the Academia Europaea, the Leopoldina, the American Academy of Arts and Sciences, and the Polish Academy of Sciences. He was President of the Swiss Academy of Medical Sciences, of the International Union of Physiological Sciences, of the Fleischner Society, and of the International Society for Stereology. He is author of Morphometry of the Human Lung (1963), the Pathway for Oxygen (1984), and Symmorphosis (2000).
Abstract
AcinusEntr is a scanning EM of a small bronchiole leading into the acinus the gas exchange region
The lung is organized into millions of microscopic gas exchange units where air in alveoli and blood in capillaries come into close contact over a very large internal surface area. How important is this for establishing favourable conditions for efficient gas exchange? Anecdotal evidence from pathology tells us that a loss of gas exchange surface, as occurs in emphysema, can lead to severe impairment of gas exchange and limitation of work capacity. But the real test must be based on quantitative experimental studies of structure–function relationships on the basis of models that combine physiology and morphometry to determine an ideal value of pulmonary diffusing capacity. This shows that the human lung is provided with some excess diffusing capacity by about 30%, but there are good reasons why this can be useful or even critical. The exceptional design features of the pulmonary gas exchanger pose a number of problems, such as how to ensure its mechanical stability, or how to ventilate and perfuse this very large surface, nearly the size of a tennis court, evenly and efficiently. To this end the airways and blood vessels form parallel branching trees. Their basic properties of fractal trees allow airway dimensions to be near optimal to minimize resistance. Very special conditions prevail, however, in the most peripheral parts of the airway tree, the acinus, where alveolar gas exchange may interfere with the need to allow oxygen to reach the most peripheral alveoli. This all taken together is what makes a good lung.
