The migration of blood cells of the bone marrow through the sinusoidal wall

Abstract

Abstract Electron microscopic observations on the mechanically undisturbed guinea pig bone marrow show that the sinusoidal lining is continuous. There are neither intercellular nor intracellular apertures allowing free communication between the extravascular and intravascular compartments. A transient migration pore is only formed during the diapedetic transit of blood cells. Serial sections show that this aperture is transcellular. A functional continuity of the sinusoidal lining appears to be maintained during the diapedesis of blood cells, which is evident from the absence of a significant extravascular leakage of plasma during this process.