Lymphocyte Migrating Through an HEV
Thin section of the same HEV viewed under an electron microscope. A lymphocyte is seen squeezing between endothelial cells through an opening in the vessel's basement membrane. The narrowest "waist" of the lymphocyte is about one micron across. An endothelial cell nucleus (E) is seen at the bottom, the node's diffuse cortex is at the top.