
Large vein
At higher magnification, the components of the three tunics are evident. In the tunica intima, smooth muscle fibers are present in the connective tissue beneath the endothelium; the elastin stain clearly shows the internal elastic lamina. Large collagen bundles and circularly arranged smooth muscle comprise the tunica media. The tunica adventitia contains longitudinally oriented smooth muscle fibers and collagen. 400x

Tunica intima
At higher magnification, the components of the three tunics are evident. In the tunica intima, smooth muscle fibers are present in the connective tissue beneath the endothelium; the elastin stain clearly shows the internal elastic lamina. Large collagen bundles and circularly arranged smooth muscle comprise the tunica media. The tunica adventitia contains longitudinally oriented smooth muscle fibers and collagen. 400x

- Endothelium
At higher magnification, the components of the three tunics are evident. In the tunica intima, smooth muscle fibers are present in the connective tissue beneath the endothelium; the elastin stain clearly shows the internal elastic lamina. Large collagen bundles and circularly arranged smooth muscle comprise the tunica media. The tunica adventitia contains longitudinally oriented smooth muscle fibers and collagen. 400x

- Internal elastic lamina
At higher magnification, the components of the three tunics are evident. In the tunica intima, smooth muscle fibers are present in the connective tissue beneath the endothelium; the elastin stain clearly shows the internal elastic lamina. Large collagen bundles and circularly arranged smooth muscle comprise the tunica media. The tunica adventitia contains longitudinally oriented smooth muscle fibers and collagen. 400x

Tunica media
At higher magnification, the components of the three tunics are evident. In the tunica intima, smooth muscle fibers are present in the connective tissue beneath the endothelium; the elastin stain clearly shows the internal elastic lamina. Large collagen bundles and circularly arranged smooth muscle comprise the tunica media. The tunica adventitia contains longitudinally oriented smooth muscle fibers and collagen. 400x

Tunica adventitia
At higher magnification, the components of the three tunics are evident. In the tunica intima, smooth muscle fibers are present in the connective tissue beneath the endothelium; the elastin stain clearly shows the internal elastic lamina. Large collagen bundles and circularly arranged smooth muscle comprise the tunica media. The tunica adventitia contains longitudinally oriented smooth muscle fibers and collagen. 400x

- Elastic fibers
At higher magnification, the components of the three tunics are evident. In the tunica intima, smooth muscle fibers are present in the connective tissue beneath the endothelium; the elastin stain clearly shows the internal elastic lamina. Large collagen bundles and circularly arranged smooth muscle comprise the tunica media. The tunica adventitia contains longitudinally oriented smooth muscle fibers and collagen. 400x

Smooth muscle fibers
At higher magnification, the components of the three tunics are evident. In the tunica intima, smooth muscle fibers are present in the connective tissue beneath the endothelium; the elastin stain clearly shows the internal elastic lamina. Large collagen bundles and circularly arranged smooth muscle comprise the tunica media. The tunica adventitia contains longitudinally oriented smooth muscle fibers and collagen. 400x

Collagen
At higher magnification, the components of the three tunics are evident. In the tunica intima, smooth muscle fibers are present in the connective tissue beneath the endothelium; the elastin stain clearly shows the internal elastic lamina. Large collagen bundles and circularly arranged smooth muscle comprise the tunica media. The tunica adventitia contains longitudinally oriented smooth muscle fibers and collagen. 400x

Image source >
Image taken from a slide in the University of Mississippi collection.