This image image from a section of the esophagus shows a small artery (center
of the image) in cross section. The endothelial cell lining (tunica intima)
is highly folded and several endothelial cell nuclei
are seen in cross section, bulging into the lumen of the vessel. The wall
contains several layers of smooth muscle cells
(tunica media), the nuclei
of which can be seen cut in longitudinal section, wrapping around the tunica
intima. The tunica adventitia (outermost
layer) composed of collagen fibers is continuous with the surrounding connective
tissue.
