The principle of adequate design and the cardiovascular system

The principle of adequate design (N. Rashevsky,Mathematical Biophysics, 3rd Ed., Vol. II, Dover Publications, Inc., New York, 1960) is applied to some parts of the cardiovascular system, extending the work of David Cohn (Bull. Math. Biophysics,16, 59–74, 1954;ibid.,17, 219–227, 1955). In addition to the diameterr _a of the aorta and the peripheral resistanceR, calculated by Cohn, other quantities are estimated as to their order of magnitude. It is shown that the specifications of the average metabolic rate lead, from considerations of design, to the possibility of evaluating the orders of magnitude of the average blood pressure, the systolic and diastolic pressures, stroke volume of the heart, duration of the cardiac period and the volume elasticity of the aorta. The calculated values are of the correct orders of magnitude. The purpose of the paper is to illustrate how the application of the principle of adequate design can lead to the evaluation of the above parameters from purely theoretical considerations, rather than from indirect measurements.