This chapter reviews some of the important arterial pressure control mechanisms and helps develop an overall concept of long-term arterial pressure regulation. It discusses the basic mechanisms of hypertension. Arterial pressure is not controlled by a single mechanism but by several mechanisms, each of which plays its specific role. The chapter illustrates the degree of response of eight of the more important pressure control mechanisms following a sudden change in arterial pressure caused by some acute effect such as rapid hemorrhage. Each of the mechanisms immediately attempts to return the pressure back toward the normal level. The chapter focuses on the baroreceptor mechanism for acute pressure control and the renal-blood volume pressure control mechanism for long-term pressure control. The baroreceptor system functions as an important arterial pressure damping mechanism to prevent rapid changes in arterial pressure but not to prevent long-term changes. It is important that the baroreceptor system has the capability of resetting its control pressure level to high or low pressures because this allows the damping mechanism to function effectively at all pressure levels.

This paper addresses two different topics: a) the concept of whole body autoregulation; and b) the role of the kidneys for long-term blood pressure regulation. In the minds of most persons in the field of hypertension research, these are interdependent phenomena. However, this is quite untrue. One of the purposes of this paper will be to point out the independence of these two phenomena, to show that each one of them can function independently of the other—though, at times, they do function together.