Control of Total Systemic Vascular Capacity by the Carotid Sinus Baroreceptor Reflex
Artin A. Shoukas,Kiichi Sagawa +1 more
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The reflex controls the total systemic venous capacity to a degree that changes cardiac output potentially by 30–10% per 25-mm Hg change in ISP, which is consistent with quantitative understanding of carotid sinus baroreceptor reflex control of cardiac output.Abstract:
To attain a quantitative understanding of carotid sinus baroreceptor reflex control of cardiac output, we studied the reflex control of total systemic vascular capacity in vagotomized dogs. In experiments measuring blood volume shifts caused by the carotid sinus reflex (series 1), venous return was diverted into a reservoir while cardiac output and central venous pressure were maintained at constant levels. The pressure in the isolated carotid sinuses (ISP) was lowered or raised in 25-mm Hg steps between 75 and 200 mm Hg. This procedure mobilized blood into or out of the reservoir, indicating a decrease or an increase in total vascular capacity, respectively. The mean maximum volume shift, 3.6 ml/kg body weight, occurred in the same ISP region, 135 ± 12.5 mm Hg, where reflex control of total peripheral resistance was strongest. The total volume shift was approximately 7.5 ml/kg for ISP changes from 75 to 200 mm Hg. When mean arterial blood pressure was maintained constant during the ISP step changes, the ...read more
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References
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Reflexogenic Areas of the Cardiovascular System
TL;DR: Experiments done between 1877 and 1926 showed that a rise of blood pressure in the carotid-cephalic circulation induces bradycardia and a fall of the systemic arterial pressure, while a drop in the vehicle pressure provokes acceleration of the heart rate and a rise in the systemicarterial pressure.
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Servoanalysis of carotid sinus reflex effects on peripheral resistance.
Allen M. Scher,Allan C. Young +1 more
TL;DR: Heymans and Neil have summarized present knowledge of the reflex and identified the baroceptors of the carotid sinus and aortic arch which reflexly control the systemic blood pressure.
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The Participation of the Venomotor System in Pressor Reflexes
TL;DR: In dogs anesthetized with chloralose, innervated loops of intestine were isolated so as to permit periodic interruptions of blood flow to record pressure-volume diagrams from the venous bed, interpreting direct evidence of venoconstriction accompanying pressor responses of the cardiovascular system.
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Total Systemic Vascular Compliance Measured as Incremental Volume-Pressure Ratio
Artin A. Shoukas,Kiichi Sagawa +1 more
TL;DR: A method to measure the compliance, defined as ΔVΔP, of the total systemic vascular bed (Ct) without stopping systemic flow is developed and indicated no significant difference between measurements of bleeding and reinfusion, measurements with different initial venous pressures or blood volume, or measurements before and after vagotomy.