The document summarizes the key components of arteries, capillaries, and venules. It describes how the intima of small arteries appears as a "dotted line" of endothelial cell nuclei due to post-mortem contraction wrinkling the endothelium. It notes that the media is the thickest and most conspicuous layer, containing clearly visible smooth muscle cell nuclei. The adventitia does not form a distinct layer and instead merges with surrounding connective tissue. Letters in the image denote specific structures, with E labeling the endothelium, F the internal elastic lamina, and G, H, I, and J labeling arterioles and venules.

1. A R T E R I E S , C A P I L L A R I E S A N D V A N U L E S
D R A M I T H A G
D E P T O F O R A L A N D M A X I L LO FA C I A L PAT H O LO G Y

7. capillary

9. ARTERY ARTERIOLE VENULES

10. The intima of the small artery is visible only as a
"dotted line" of nuclei of endothelial cells, exactly
at the edge of the arterial lumen. These nuclei
look round rather than flat because post-mortem
contraction of smooth muscle in the media has
caused longitudinal wrinkles in the endothelium.
The internal elastic lamina is inconspicuous.
The media is the thickest, most conspicuous layer,
in which nuclei of individual smooth muscle
fibers are clearly visible.
The adventitia is not a distinct layer but merges
with surrounding connective tissue.

12. E is the endothelium - in preparation, contraction of the muscle causes the endothelial nuclei to round up and
bulge into the lumen.
Don't let this confuse you - it is still simple squamous epithelium.
F is the internal elastic lamina.
The subendothelial connective tissue is not visible.
Both G and I are arterioles and
H and J are venules.