1. Cardiovascular System
The cardiovascular system (CVS) is composed of:
Heart
Blood vessels
Arteries
Capillaries
Veins

2. Heart
It is formed of three layers:
Endocardium
Myocrdium
Epicardium

3. Endocardium Composed of: Endothelium (simple squamous epithelium)
Subendothelial layer of fibroelastic connective tissue

4. Myocardium Forms the main bulk of the wall of the heart
Composed of cardiac muscle fibers, arranged in spirals around the orifices of the chambers

5. Epicardium Outermost layer
Also called the visceral layer of pericardium
Composed of simple squamous epithelium
The subepicardial layer of loose connective tissue contains the coronary vessels, nerves, ganglia and fat

6. Histologically blood vessels can be divided as:
Large (Conduction, Elastic) arteries
Medium size (Muscular) arteries
Arterioles
Capillaries
Venules & small veins
Medium veins
Large veins

7. General Structure of Blood Vessels
Formed of three concentric layers:
Tunica intima (interna)
Tunica media
Tunica adventitia (externa)

8. Tunica Intima Is the innermost layer Composed of:
Single layer of flattened endothelial cells (resting on the basal lamina) lining the lumen of the vessel
Subendothelial layer made up of loose connective tissue.
Beneath the subendothelial layer is an internal elastic lamina, composed of elastin (fenestrated sheet), separating the tunica intima from the tunica media

9. Tunica Media Intermediate layer Is the thickest layer
Composed of smooth muscles, some elastic fibers, and collagen Large muscular arteries have external elastic lamina, separating the tunica media from the tunica adventitia
Capillaries do not have a tunica media.

10. Tunica Adventitia Outermost layer
Composed of connective tissue containing type I collagen, fibroblasts and elastic fibers

11. The tunica media and adventitia of large vessels (especially veins) are nourished by the vasa vasorum, which are small arteries that enter the vessel wall and branch to supply both tunicae M VV A

12. Elastic Arteries
Intima characterized by the presence of subendothelial lamina of elastic fibers in addition to the internal elastic lamina
Media consists of many fenestrated elastic membranes (lamellae) alternating with few smooth muscle fibers.
They also have an external elastic lamina.
Tunica adventitia is thin and has vasa vasorum
Examples: aorta.

13. Muscular Arteries
Most of the rateries arising from aorta are muscular arteries
Internal elastic lamina is very prominent
Media is formed mainly of smooth muscle fibers
External elastic lmina is prominent in large muscular arteries

14. Capillaries Very small vessels
Consist of a single layer of endothelial cells surrounded by a basal lamina & occasional pericytes
Are responsible for the exchange of gas, metabolites and other substances between the blood and the tissues of the body

15. Veins Generally they have: Larger lumina Thinner walls
Fewer layers of smooth muscle fibers than their companion arteries
Prominent connective tissue components than their companion arteries
Valves in the lumen

16. Medium-sized Veins
Intima is thin, formed of endothelium, basal lamina and few elastic fibers
No internal elastic lamina
Media is thin containing few smooth muscle intervowen with collagen fibers and fibroblasts
Adventitia is the thickest layer, composed of longitudinally arranged collagen & elastic fibers and few smooth muscle cells
They have valves formed of thin fold of intima

17. Comparison of Artery & Vein

18. Neurovascular Bundle

19. Practical Slides
Practical Slides
Practical Slides

20. Elastic Artery

21. Medium-sized (Muscular ) Artery

22. Medium-sized Vein

23. Thank U & Good Luck