To the interstitial space - and beyond!

摘要

In clinical practice, the elements of the circulation that receive most attention are the heart and blood vessels, despite the fact that 'the heart and vasculature exists for one fundamental purpose: the delivery of metabolic substrate to the cells of the organism' (Levick, 1991). Attitudes to this 'fundamental purpose' vary. The book cited here assigns nearly 20% of its text to these processes, although another similar basic textbook devotes a mere 5%, and generally the emphasis in medical teaching is on the arterial side of the circulation. One of the reasons for this blind spot may be that scientists, and clinical scientists in particular, tend to study features that are accessible, where equipment and methods are available, and where interest already lies. Thus despite the common definition of shock as 'where vital tissues are inadequately perfused', consideration of the processes that govern exchange from the capillary to the cell, and interest in the regulation of the medium in which this exchange occurs, are remarkably limited in clinical science. The lymphatic tree that flows from the tissues is a challenge to our knowledge. Its function may in many respects mirror the better known vasculature: it has mechanical, hydraulic and regulatory systems that are vital to tissue life, and indeed there may be some very analogous control of blood and lymph vessels.