If you were to look at histological slides of both arteries and veins, you will notice 3 layers of tissue called tunics. In both, the inner most tunic, the tunica intima, is made up of epithelial tissue and forms a tube that blood travels through. Surrounding this is the muscular tunica media, which controls the diameter of the blood vessel, and this is surrounded by a layer of connective tissue called the tunica externa. To control blood flow arteries have a thick tunica media. As a result, the diameters of arteries tend to be narrower than veins. Veins tend to have thinner walls since there is no pressure in veins. Furthermore, since there is no pressure, veins have valves that prevent back flow of blood. Your veins also have quite large diameters. This is because veins act as reservoir of blood. Therefore, the arteries and veins of the human body are the super highways in which large amounts of blood travel. Both vessels have three layers (tunics); an inner layer of epithelial tissue (the endothelium), a muscular layer and then fibrous connective tissue layer. Those layers are called, in order, the tunica intima, the tunica media, and the tunica externa. Major arteries and veins also have elastic tissue distributed through the three tunics as well.
These pictures were taken by me at various times. Most are sets of 3 where they show a both an artery and vein, then a closeup of an artery and finaly a closeup of a vein. Go through the pictures. Select one artery and one vein and draw them. Then Label the layers. This model is of what his histology slide should look like.
| Labeled Image | Unlabeled Images |
|---|---|
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1/11
Artery and Vein
2/11
Artery
3/11
Vein
4/11
Artery and Vein
5/11
Artery
6/11
Vein
7/11
artery and vein
8/11
Artery
9/11
Vein
10/11
In Muscle
11/11
In Connective Tissue
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