This high magnification
image shows a cross section through an arteriole
The nuclei of the endothelial cells (En) that
form the tunica intima are seen in cross section, indicating that they are
oriented with their long axes parallel to the long axis of the blood vessel.
The endothelial cell layer is covered with approximately three layers of smooth
muscle cells, whose nuclei (SM) are cut in longitudinal
section, indicating that they are oriented with their long axes perpendicular
to the long axis of the vessel.
