Masamitsu Oshima

Measurement of the transfer function of the carotid sinus pressure control system with its feedback loop physiologically closed

Tim TRANSFER characteristic of the carotid sinus pressure control system had been studied quantitatively by SCI-mR and YOUNG (1963) and LEVlSON et al. (1966). In their studies the carotid sinus was isolated from the circulation of the common carotid artery and supplied with blood from another artery. Therefore the reflex system which had been physiologically closed was opened and the transfer characteristic was studied with the intrasinual pressure artificially controlled. We obtained the transfer characteristic of the reflex system by a method where the physiological closed system was not opened and a disturbance of a pressure pulse was superimposed on the intrasinual pressure. The subsequent transient response of the aortic and intrasinual pressure was recorded and analysed to calculate the transfer function of the system.

FATIGUE IN AUTOMOBILE DRIVERS DUE TO LONG TIME DRIVING

Physiological and psychological responses due to 10 hours day driving and 24 hours driving were gathered from passenger car drivers in order to study drivers fatigue. These responses were classified into three groups. It was made clear that functions of the central nervous system were the most important for driving among other functions. Biological rhythm was closely concerned with the reserve power of driving performance.

A design of an artificial control system of the cardiac output

SummaryAn automatic control system of the cardiac output of a dog was designed by a method where a cardiac vagus and the heart were involved in the feedback system. The cardiac output was measured at the ascending aorta by a sine wave electromagnetic flowmeter. The output voltage of the flowmeter was compared with a controllable reference voltage. The error voltage was amplified or integrated, and converted to pulses of the frequencies which was proportional to the input of the AD convertor. A peripheral cut end of a vagus was stimulated by an electric stimulator triggered by those pulses. Vagal stimuli decrease the cardiac output by their negative chronotropic and inotropic action. The error approximated zero when the feedback loop gain was more than about 10 or an integral control was used. Complete stability could not be achieved with a zero error and an unstable oscillation of the smoothed cardiac output signal with a period of several seconds was observed. However, the instability was slight and did not disturb its application. Effects of disturbances such as change of venous return and peripheral resistance were sufficiently reduced.