The following are labeled in the diagram:

1. Artery:
   1. Connective tissue with the text “helps vessels especially arteries, expand under pressure and connects them to surrounding tissue.”
   2. Smooth muscle with the text, “regulates the diameter of arteries; only a thin layer present in veins.”
   3. Arteriole with the text, “very small arteries that deliver blood to capillaries.”
   4. Endothelium
2. Capillary: An enlarged image of capillary is shown and endothelium is labeled.
3. Vein:
   1. Venule with the text, “very small vessels that form when capillaries unite; venules unite and form veins.”
   2. Connective tissue
   3. Smooth muscle
   4. Endothelium with the text, “lines the walls of all blood vessels.”