Arteriole and venule
An arteriole consists of a tunica intima, a thin tunica media of one to two layers of smooth muscle cells and a tunica adventitia. The wall of the adjacent venule is thinner and less regular, consisting only of an endothelium, forming the tunica intima. A tunica media is absent and the thin tunica adventitia is indistinguishable from the surrounding connective tissue. 1000x
Arteriole
An arteriole consists of a tunica intima, a thin tunica media of one to two layers of smooth muscle cells and a tunica adventitia. The wall of the adjacent venule is thinner and less regular, consisting only of an endothelium, forming the tunica intima. A tunica media is absent and the thin tunica adventitia is indistinguishable from the surrounding connective tissue. 1000x
Venule
An arteriole consists of a tunica intima, a thin tunica media of one to two layers of smooth muscle cells and a tunica adventitia. The wall of the adjacent venule is thinner and less regular, consisting only of an endothelium, forming the tunica intima. A tunica media is absent and the thin tunica adventitia is indistinguishable from the surrounding connective tissue. 1000x
Tunica intima >
The thin tunica intima of the arteriole is clearly visible along with its highly reduced internal elastic lamina, which is particularly evident in the lower half of the vessel. In the venule, the basophilic cytoplasm of the endothelial cells is indicated.
Tunica media
An arteriole consists of a tunica intima, a thin tunica media of one to two layers of smooth muscle cells and a tunica adventitia. The wall of the adjacent venule is thinner and less regular, consisting only of an endothelium, forming the tunica intima. A tunica media is absent and the thin tunica adventitia is indistinguishable from the surrounding connective tissue. 1000x
Tunica adventitia
An arteriole consists of a tunica intima, a thin tunica media of one to two layers of smooth muscle cells and a tunica adventitia. The wall of the adjacent venule is thinner and less regular, consisting only of an endothelium, forming the tunica intima. A tunica media is absent and the thin tunica adventitia is indistinguishable from the surrounding connective tissue. 1000x
Capillaries
An arteriole consists of a tunica intima, a thin tunica media of one to two layers of smooth muscle cells and a tunica adventitia. The wall of the adjacent venule is thinner and less regular, consisting only of an endothelium, forming the tunica intima. A tunica media is absent and the thin tunica adventitia is indistinguishable from the surrounding connective tissue. 1000x