1. CARDIOVASCULAR SYSTEM BLOOD VESSELS
General Organization
Arteries
Large (Elastic) Arteries
Muscular (Distributing) Arteries
Arterioles (Small) Arteries
Precapillary (Terminal) Arterioles
Capillaries
Veins
Venules
Medium Veins
Large Veins
Lymphatics

2. General Organization Blood Vascular System Portal System
Lymph Vascular System

3. Tissue Components Endothelium Elastic elements Muscular elements
Connective tissue elements

4. Arteries - General Structural Plan
Tunica Intima
Tunica Media
Tunica Adventitia
Arteriosclerosis

5. Tunica Intima Endothelium Basement membrane
Subendothelial connective tissue
Internal elastic lamina (IEL)

6. Tunica Media
Smooth muscle
Elastic fibers/lamina

7. Tunica Adventitia External elastic lamina (EEL) Connective tissue
Vasa vasorum
Sympathetic nerves

9. Arteriosclerosis - “Hardening of Art.”
Atherosclerosis
Monckeberg’s Medical Calcific Sclerosis
Arteriolosclerosis

12. Myointimal Cells Intimal smooth muscle cells
Potential of fibroblasts, macrophages & SM
Foam cells (lipophages)

14. BV CLASSIFICATIONS Arteries Capillaries Veins Large (Elastic)
Medium (Muscular)
Small (Arterioles)
Capillaries
Continuous
Sinusoids
Lymphatics
Veins
Small (Venules)
Medium
Large (Cava)

15. Large (Elastic) Arteries
Tunica intima
thicker subendothelial c.t.
poorly defined IEL
Tunica media - thickest, largely elastic
Tunica adventitia
EEL poorly defined
vasa vasorum

17. Muscular (Distributing) Arteries
Tunica intima - thin with prominent IEL
Tunica media - largely smooth muscle
Tunica adventitia
thick with prominent EEL
vasa vasorum, lymphatics, nerves

19. Arterioles (Small Arteries)
Tunica intima - absence of IEL
Tunica media - gradual reduction in layers
Tunica adventitia - no EEL

22. Precapillary (Terminal) Arterioles
Metarterioles
no IEL
1-2 smooth muscle cells
serve as AV shunts
true capillaries are branches
Precapillary Sphincters
guard openings of true capillaries

24. Capillaries - General Structural Plan
Endothelium
Basement Memb.
Pericytes
Other Cells

25. Endothelium Cells elongated along capillary axis
Attached by both occluding (tight) and communicating (gap) junctions
Oval or elongated nucleus (bulges into lumen)
Contractile - cytoplasmic filaments
Pinocytotic vesicles and vacuoles

27. Basement Membranes
Continuous in blood vascular system (prominent in brain as BBB)
Discontinuous in sinusoids and lymphatics
Collagen Type IV
Elastic fibers

28. Pericytes Enclosed in own basement membrane
Discontinuous and irregularly spaced
Particularly numerous in brain (BBB)
Nucleus bulges away from lumen

30. Other Cells Fixed macrophages Mast cells - secrete heparin
Rare nerve fibers

31. Capillary Function Barrier Exchange Forces Endocapillary layer
Endothelium
Basal lamina and pericytes
Adventitia
Exchange Forces
Hydrostatic
Osmotic
Concentration

32. Capillaries - Structural Types
True Capillaries
Continuous capillaries
Fenestrated capillaries with diaphragms
Fenestrated capillaries without diaphragms
Sinusoids
Lymphatic Capillaries

34. Venules (Small Veins) Tunica intima - endothelial tube Tunica media
Pericytes
Isolated smooth muscle cells
Tunica Adventitia - minimal

38. Medium Veins Tunica intima - thin, forms valves
Tunica media - scattered smooth muscle
Inner layer longitudinally arranged in large veins
Tunica adventitia - thick with longitudinal

41. Large Veins Tunica intima - slightly thicker than medium
Tunica media - sparse smooth muscle cells
Tunica adventitia - thick with longitudinal bundles of smooth muscle cells

44. Lymphatics Tunica intima & adventitia only
Discontinuous basement membrane
Very frequent valves
Anchoring filaments
Extensive vasa vasorum
Lymphangion
Interposed lymph node filters
Drain into veins

46. BV CLASSIFICATIONS Arteries Capillaries Veins Large Elastic lamina
Medium >10 SM layers
Small (Arterioles) <5 SM layers
Capillaries
Continuous (Fenestrated & Non-Fenestrated)
Sinusoids (Liver, spleen, lymph nodes, BM)
Lymphatics (Everywhere)
Veins
Small (Venules) Thin wall, large lumen
Medium Few layers of SM, “
Large (Cava) Long. SM in Adv.