The Circulating Blood in Relation to Wound-Shock

Abstract

THE system of vessels in which the blood is contained must be conceived of as a closed system. But the walls are distensible and elastic; they can therefore stretch and collapse to accommodate varying amounts of liquid. This is possible, however, only to a limited extent. Although the veins have thinner walls than the arteries, and appear to be less supported by surrounding structures than are the capillaries, it is remarkable that they oppose a greater resistance to a bursting pressure than do the arteries. Veins, moreover, have a muscular coat which is in a more or less contracted state during life. Hence the introduction of more fluid into the system must encounter a certain resistance and raise the internal pressure, unless the muscular coat actively relaxes to accommodate the fluid introduced.