This image shows a longitudinal section through a small artery in
the connective tissue of the lip. From the lumen outwards can be seen:
1) erythrocytes and
nucleated white blood cells; 2) simple squamous epithelium with,
elongated flattened nuclei of endothelial
cells; 3) internal
elastic lamina; 4) 3-4 layers of smooth muscle cells, with nuclei
cut in cross section; 5) a relatively thick layer of connective
tissue containing the elongated, flattened nuclei of fibroblasts.
