Histology for Pathology Circulatory System. Theresa Kristopaitis , MD Associate Professor Director of Mechanisms of Human Disease Kelli A. Hutchens, MD, FCAP Assistant Professor Assistant Director of Mechanisms of Human Disease Loyola Stritch School of Medicine. OBJECTIVES.
Theresa Kristopaitis, MD
Director of Mechanisms of Human Disease
Kelli A. Hutchens, MD, FCAP
Assistant Director of Mechanisms of Human Disease
Loyola Stritch School of Medicine
1. Given a histologic section of a large or medium sized artery, identify the
a) tunica intima
b) tunica media
c) tunica adventitia
2. Identify the following structures in a histologic section of an artery
b) Internal elastic lamina
c) External elastic lamina
3. Distinguish the characteristics which separate large, medium and small arteries and arterioles.
4. In a tissue section, distinguish a medium sized artery from a medium sized vein
5. In a tissue section identify capillaries, describe their structure and function
6. Compare and contrast general structural features of the arterial vs venous system
7. Describe the structure and function of a lymphatic vessel
a = tunica intima - endothelial lining plus thin layer of underlying connective tissue called the subendothelium.
b = tunica media - alternating layers of elastic membranes (elastic lamina) and smooth muscle.
c = tunica adventitia - fairly dense connective tissue carrying small blood vessels,
the vasa vasorum
Endothelium: Composed of single layer of squamous cells, provides a permeable barrier, angiogenesis, release of single molecules.
Also called muscular artery because the wall is dominated by smooth muscle.
Similar to large artery but internal and external elastic lamina are well defined and lack prominent vasovasorum.
Small Arteries: Generally have same structure as medium artery but have a smaller diameter and no external elastic lamina. The tunica media also has fewer layers of smooth muscle cells.
Arterioles: The smallest arteries, lead blood flow into capillary beds. Only two layers of smooth muscle cells. Internal elastic lamina, external elastic lamina, and subendothelial layers usually absent.
A capillary lying in the endomysium between skeletal muscle fibers. This one shows very dark endothelial nuclei and has 3 pink red blood cells* lined up in a row inside
Medium-sized vein with a much less compact muscle layer than in arteries.
a - tunica media
b – tunica adventitia, which is at least as wide as the media, and often even wider.
Smooth muscle bundles
Quite similar to a large vein but smaller lumen, tunica adventitia contains fewer bundles of longitudinal smooth muscle and vasa vasorum is not prominent.
Smooth muscle bundles
Thinned walled vessels with large lumens and valves. There are some fat cells and lymphocytes in the surrounding connective tissue.