histology of blood vessels

Tunica intima is covered by flat layer cells which is endothelium

elastic artery

characteristic:
- very thick tunica media which contains elastic fibers
- tunica intima is covered by endothelium which is flat cells
- small blood vessels of vasa vasorum are present in tunica adventitia layer

muscular artery

characteristic:
- consist internal elastic lamina at tunica intima
- tunica intima is covered by flat cells of endothelium
- thick runica media which contains elastic fibers
- has small blood vessels of vasa vasorum inside tunica adventitia

vein

characteristics
- thin tunica media
- thick tunica adventitia which contains many smooth muscle fibers
- tunica intima is covered by layer of flat cells of endothelium

• AV bundle is located in the membranous IVS
• It is the only electrical bridge between atria and ventricles
• Splits into right and left bundle branches
• Bundle branches continue as Purkinje fibres
• Purkinje fibres cause rapid, coordinated ventricular contraction
• Purkinje fibres are NOT nerves

• Modified cardiac muscle cells
• Located in subendocardium
• Large, pale cells
• 1–2 centrally placed nuclei
• Sparse peripheral myofibrils
• Cytoplasm rich in glycogen & mitochondria
• Conduct impulses to ventricular myocardium