A Tandem Forearm Plethysmograph for Study of Acute Responses of the Peripheral Veins of Man: The Effect of Environmental and Local Temperature Change, and the Effect of Pooling Blood in the Extremities1

Abstract

The primary mechanism of action of the smooth muscle of the veins upon their contained blood is one of imparting pressure to the blood by a surrounding force. This mode of action is to be distinguished from that of the smooth muscle of the arterioles, which is one of maintenance of arterial pressure through resistance to the outflow of blood. The function of the arterioles as resistive elements in the circulation is evaluated by the relationship between the volume of the flow of blood through the arterioles per unit period of time and the change in pressure across the arterioles. The function of the veins as containers of the blood volume is best evaluated by the relationship between a change of the volume of the veins and the associated change of the pressure of the veins.It is the purpose of this paper to describe a new method for the simultaneous study of the functions of the arterioles and the veins of the extremities of man. In addition, the effects of several stimuli upon veins and arterioles of the forearm are also described. The stimuli employed were the reduction of the temperature of the room, the reduction of the temperature surrounding the forearm under study, and the congestion of the veins of the three extremities not being studied. METHODSA water plethysmograph made of lucite which had two chambers was used in all of the experiments (Figure 1). Each chamber was 8.5 cm. long and had separate sleeves which were thin, loose fitting rubber. The

Studies on Starling's Law of the Heart. I. The Circulatory Response to Acute Hypervolemia and Its Modification by Ganglionic Blockade

“…Pertinent to this possible explanation of the data obtained are those studies which have demonstrated that venous tone in man is not constant, but may be altered by a variety of stimuli (30)(31)(32)(33)(34). In particular, ganglionic blockade produces venodilatation in patients in congestive heart failure (35,36) and in normal subjects during muscular exercise (34).…”

The Cardiovascular Effects of Morphine THE PERIPHERAL CAPACITANCE AND RESISTANCE VESSELS IN HUMAN SUBJECTS

“…This was to insure that the subjects were comfortable but cool. We specifically did not want to induce venodilation or arteriolar dilation by having the subjects in a warm environment (23). A single strand mercury-inrubber strain gauge (24) was utilized for measurements of forearm venous tone and blood flow as described below.…”

Lack of tolerance in forearm blood vessels in man to glyceryl trinitrate.

“…Dilatation is likely to be limited by the degree of resting tone in the veins; when this is overcome, no further venodilatation is possible. In their study of the physiology of forearm veins Wood & Eckstein [11] state that under normal laboratory conditions these vesels have no resting tone. Lack of basal tone was also demonstrated in the studies of Greenfield & Patterson [12].…”