Our program of research has been involved with the study of the different phases of circulatory dynamics and their control. Both normal and abnormal controls are being studied since many diseases such as hypertension, shock, edema, neurogenic and endocrine disorders, and renal diseases are manifestations of abnormal circulatory control. Emphasis is being placed on the development of an overall quantitative mathematical model of the body's circulatory system, which is in accord with both normal physiology and pathological states. The mathematical analysis requires a quantitative description of the different systems and subsystems involved in circulatory control as well as the interrelationships between them. Experimental data from our laboratory is used to update the data for the model. Research is being conducted in two phases. First, appropriate measurements of various quantitative relationships within the circulatory system are made in the different laboratories supported by the Program Project. Second, the data provided from animal experimentation is used to expand and redefine our mathematical analysis - particularly the current version of the large model of the overall control of the circulation. In turn, the mathematical analyses provide the basis for much of the new animal experimentation. BIBLIOGRAPHIC REFERENCES: Coleman, T.G., A.C. Guyton, A.W. Cowley, Jr., D.B. Young, J.W. Declue, and A. Cevese. Renal abnormalities that do and do not cause hypertension. Proc. 6th Int. Congress Nephrol., 1975. Young, D.B. Neural Control of Fluid volumes: I. Volume Receptors and Autonomic Control. In: Circulatory Physiology, Vol. II: Body Fluid Dynamics and Regulation. Ed. A.C. Guyton, A.E. Taylor, and H.J. Granger, 1975.