Pressure is the force applied per unit area. In hemodynamics we always think of pressure in terms of a pressure difference. The pressure difference along the axis, or pressure gradient, is the pressure that causes the flow of blood. The pressure difference between the inside and outside of a vessel or the heart, which is often called transmural pressure, causes the wall distension.
- 1.Munson BR, Young DF, Okiishi TH. Fundamentals of fluid mechanics. 1994, New York, Wiley.Google Scholar