the disk in the fundus of the eye marking the point at which the optic nerve enters; it is accompanied by blood vessels, is oval, light in color and the blind spot of the retina.
ARTERIOLES. In arterioles, the tunica intima consists of a continuous endothelium and a very thin subendothelial layer. In addition, a thin, fenestrated internal elastic lamina is present in larger arterioles but absent in terminal arterioles. Generally, the tunica media consists of 2 layers of smooth muscle cells.
3 Artery tunics. Tunica interna (intima) - innermost-composed of simple squamous epithelium called endothelium-epithelial tissue lines the inside of hollow organs.Tunica media-middle layer. This layer is much thicker in arteries than in veins. Smooth muscle Tunica externa (adventitia) - outermost layer-fibrous connective tissue. Artery tunics. Tunica interna (intima) - innermost-composed of simple squamous epithelium called endothelium-epithelial tissue lines the inside of hollow organs.