Circulatory System Histology Heart Blood vessels Lymphatics BY Dr Navneet Kumar Professor Anatomy KGMU LKO Dr Navneet Kumar Professor Anatomy K G M U Lko Blood vessels • Deliver nutrients ,removes metabolic products and exchange of substances • General structure 1.Tunica intima 2.Tunica media 3.Tunica adventitia Dr Navneet Kumar Professor Anatomy K G M U Lko Blood Vessels Types (histological)- • Arteries-Large artery (Elastic artery ) -Medium sized artery (Muscular artery) -Small artery & Arterioles - Muscular arterioles - Terminal arterioles -Capillaries-Fenestrated -Continuous -Discontinuous • Veins - Large vein - Medium sized vein - Venules Dr Navneet Kumar Professor Anatomy K G M U Lko Large artery • Layers (1) Tunica intima • - Endothelium -Sub endothelial tissue- Myointimal cells -Internal elastic lamina- poorly defined (2)Tunica media -Thickest layer - many laminae of elastic fibres -Few smooth muscle cell & collagen fibre outer most- external elastic lamina (3)Tunica adventitia • -Fibro elastic tissue • -Vasa vasorum +nt Dr Navneet Kumar Professor Anatomy K G M U Lko Dr Navneet Kumar Professor Anatomy K G M U Lko Large artery • Examples • Aorta, Carotid artery subclavian artery Dr Navneet Kumar Professor Anatomy K G M U Lko Dr Navneet Kumar Professor Anatomy K G M U Lko Dr Navneet Kumar Professor Anatomy K G M U Lko Dr Navneet Kumar Professor Anatomy K G M U Lko Dr Navneet Kumar Professor Anatomy K G M U Lko Dr Navneet Kumar Professor Anatomy K G M U Lko Dr Navneet Kumar Professor Anatomy K G M U Lko Dr Navneet Kumar Professor Anatomy K G M U Lko Dr Navneet Kumar Professor Anatomy K G M U Lko Dr Navneet Kumar Professor Anatomy K G M U Lko Muscular artery • Layers • Tunica intima - Endothelium -Sub endothelial tissue very less - internal elastic lamina- very well defined and wavy • Tunica media -Thick layer - many circular laminae of smooth muscle fibres - few elastic fibres & collagen fibre • Tunica adventitia -As thick as tunica media - external elastic lamina -Fibro elastic tissue (longitudinal) -Vasa vasorum +nt Dr Navneet Kumar Professor Anatomy K G M U Lko Dr Navneet Kumar Professor Anatomy K G M U Lko Dr Navneet Kumar Professor Anatomy K G M U Lko Dr Navneet Kumar Professor Anatomy K G M U Lko Dr Navneet Kumar Professor Anatomy K G M U Lko Dr Navneet Kumar Professor Anatomy K G M U Lko Dr Navneet Kumar Professor Anatomy K G M U Lko Dr Navneet Kumar Professor Anatomy K G M U Lko Muscular artery Dr Navneet Kumar Professor Anatomy K G M U Lko Dr Navneet Kumar Professor Anatomy K G M U Lko Small artery & Arterioles • Small artery-Terminal part of muscular arteries • 5-6 layer of smooth muscle • Diameter of wall/lumen ratio is 1:2 • Lumen more than 0.1 mm • Arterioles- 2-4layer of smooth muscle cells layers • Internal elastic lamina absent • Lumen less than 0.1 mm • -Muscular arterioles- 100micron to 50 micron • -Terminal arterioles-50 to 10micron • Meta arteriols Dr Navneet Kumar Professor Anatomy K G M U Lko Dr Navneet Kumar Professor Anatomy K G M U Lko capillary Dr Navneet Kumar Professor Anatomy K G M U Lko Large vein (1) Tunica intima- - Endothelium -Sub Endothelial Tissue (2) Tunica media- Very thin, or absent Collagen fibres (3) Tunica adventitia- Thickest ,longitudinal Smooth muscles, lots of collagen fibre Dr Navneet Kumar Professor Anatomy K G M U Lko Dr Navneet Kumar Professor Anatomy K G M U Lko Dr Navneet Kumar Professor Anatomy K G M U Lko Dr Navneet Kumar Professor Anatomy K G M U Lko Medium sized vein (1) Tunica intima- - Endothelium -Sub endothelial tissue (2) Tunica media- collagen fibres and muscle cells circular layers (3)Tunica adventitia- fibro elastic and connective tissue Dr Navneet Kumar Professor Anatomy K G M U Lko Dr Navneet Kumar Professor Anatomy K G M U Lko Dr Navneet Kumar Professor Anatomy K G M U Lko Dr Navneet Kumar Professor Anatomy K G M U Lko Venule (1)Tunica intima- - only Endothelium (2) Tunica media- few circular layers muscle cells (3)Tunica adventitia- fibro elastic and connective tissue Dr Navneet Kumar Professor Anatomy K G M U Lko Dr Navneet Kumar Professor Anatomy K G M U Lko Dr Navneet Kumar Professor Anatomy K G M U Lko .