HISTOLOGY • Introduction • Cardiovascular System – Blood vessel – Heart • Lymphatic vascular System – Lymphatic vessel Introduction • Circulatory system – Cardiovascular system • to carry the blood in both directions between heart and the tissue – Lymphatic vascular system • to collect the lymph – The excess extra cellular tissue fluid • To deliver it back to cardiovascular system Circulation Aorta Medium Arteries Small Arteries (arterioles) Heart Tissue Capillaries Large Veins Medium Veins Small Veins (Venues) Blood Vessel • 3 tunics or layers – The tunica intima • The most internal layer – a single layer of flattened, squamous endothelial cells – the subendotelial loose connective tisue – the internal elastic tunic Blood Vessel • 3 tunics or layers – The tunica media • concentric smooth muscle layer, elastic fibers, type III collagen fibers and proteoglycan • external elastic lamina – more delicate than the internal elastic lamina – separates the tunica media from overlying tunica adventisia Blood Vessel • 3 tunics or layers – Tunica Adventisia • covers the outside surface of blood vessel • type I collagen fibers • vasa vasorum – the small arteries that enter the vessel walls » to give the nutrient for the wall of blood vessel Blood Vessel • Artery – efferent vessels • transport blood away from the heart to the capillary bed – classified into 3 types • Large artery (elastic artery/ conducting arteries) • Medium artery (muscular artery / distributing artery) • Small artery (arterioles) and met arterioles Circulation Large Arteries/Aorta Medium Arteries Small Arteries (arterioles) Heart Tissue Capillaries Large Veins Medium Veins Small Veins (Venues) Blood Vessel • Large artery (elastic artery/ conducting arteries) – aorta – inominate artery – carotic communis artery – subclavian artery – iliac artery Blood Vessel • Large artery (elastic artery/ conducting arteries) 1. The tunica intima • contains an endothelium • supported by the narrow layer of underlying connective tissue – The internal elastic lamina • Thin laminae of elastic fiber 2. The tunica media • consists of many fenestrated lamellae of elastin fibers • a few amount of smooth muscle • The external elastic laminae Blood Vessel • Large artery (elastic artery / conducting arteries) 3. Tunica adventisia • relatively thin, composed of loose fibroelastic connective tissue • Vasa Vasorum – the small blood vessel located in the vessel wall of large or medium artery » functions in supplying the nutrient and oxygen to that tissue Elastic artery Tuesday, April 27, 2010 AAJ/Histological Aspect of Cardiovascular System Muscular artery Tuesday, April 27, 2010 AAJ/Histological Aspect of Cardiovascular System Blood Vessel • The function of large artery – to drainage the blood to the medium artery – to keep the systolic pressure in the constan condition – to avoid the fluctuation of blood flow Large Artery Circulation Large Arteries/Aorta Medium Arteries Small Arteries (arterioles) Heart Tissue Capillaries Large Veins Medium Veins Small Veins (Venues) Blood Vessel • Medium artery – – – – – – – brachialis artery ulnar artery femoral artery poplitea artery coronary artery umbilical artery arteries located in the brain Blood Vessel • Medium artery – The tunica intima • thinner than in the elastic arteries – The internal elastic laminae • • – Prominent displays an undulating surface The tunica media • composed predominantly of smooth muscle cells Muscular artery Blood Vessel • Medium artery – The external elastic lamina • identifiable in histological sections as several layers of thin elastic sheets – The tunica adventisia • • • elastic fibers collagen fibers a ground substance – composed mostly of dermatan sulfate and heparan sulfate. Blood Vessel • The function of medium artery – is to distribute the blood to the target organ or tissue Medium artery (Muscular Artery) Muscular Artery The differences between Large and Medium Artery Circulation Aorta Medium Arteries Small Arteries (arterioles) Heart Tissue Capillaries Large Veins Medium Veins Small Veins (Venues) Blood Vessel • Small Artery – one component of microvascular sistem • arteriole, metarteriole, capillary and venule – vasoconstriction of arteriole will increase the peripheral resistency • resulting in the increasing of systemic blood pressure Blood Vessel • Metarteriole – An artery that supply blood to capillary beds – The smooth muscle layer is not continuous but spaced apart • It is thought that this arrangement permits these smooth muscle cells to function as a sphincter upon contraction – controlling blood flow into the capillary bed 36 Blood Vessel • Small Artery – Arteriole – The endothelium of tunica intima • supported by a thin subendothelium layer – consisting of type III collagen and a few elastic fibers embedded in ground substance Blood Vessel • Small Artery/Arteriole – An internal elastic lamina • • – The tunica media • – present in small arteriole absent in terminal arterioles a single smooth muscle cell layer The tunica adventisia • • Scant represented by fibroelastic connective tissue Tuesday, April 27, 2010 AAJ/Histological Aspect of Cardiovascular System Blood Vessel • Nerve supply to vessel – Sympathetic and parasympathetic • Sympathetic adrenalin vasoconstriction • parasympathetic acetylcholine vasodilatation Circulation Aorta Medium Arteries Small Arteries (arterioles) Heart Tissue Capillaries Large Veins Medium Veins Small Veins (Venues) Blood Vessel • Capillary – The smallest blood vessels arising from the terminal ends of the arterioles – capillary bed (network) between the arterioles and venules Blood Vessel • Capillary – 7-12 micrometer – formed by a single layer of squamous endothelial cells • known as endothel – lined by basal membrane – Pericytes • The cells located along the outside of the capillaries and small venules • cells are flatenned in shape and contain tropomyosin isomyosin and protein kinase – all related to contraction that regulate the blood flow Blood Vessel • Capillary – There are 3 types of capillary • Continuous capillaries – have no interruptions (pore or fenestrated) in their wall – present in the muscle, nervous and connective tissues • Fenestrated capillaries – have pore or fenestrae in their wall – present in the pancreas, intestines, endocrine and kidney Blood Vessel • Capillary – There are 3 type of capillary • Sinusoidal capilaries – known as sinusoids – have irregular shape which conform to the shape of the structure in which they are located – found in the hemopoeitic tissue such as bone marrow and spleen, liver, cortex of adrenal and adenohipophysis Pericytes Tuesday, April 27, 2010 AAJ/Histological Aspect of Cardiovascular System Circulation Aorta Medium Arteries Small Arteries (arterioles) Heart Tissue Capillaries Large Veins Medium Veins Small Veins (Venues) Blood Vessel • Veins – afferent vessel • collect and transport the blood back to the heart – 3 types • Small vein – The shape of small venule is irregular – Tunica intima of venule is lined by a single flattened cells known as endothelial cells Tuesday, April 27, 2010 AAJ/Histological Aspect of Cardiovascular System Circulation Aorta Medium Arteries Small Arteries (arterioles) Heart Tissue Capillaries Large Veins Medium Veins Small Veins (Venues) Blood Vessel • Veins – 3 types • Medium veins – similar to medium artery » but has no external elastic lamina – many medium veins have valves » composed of two leaflets a thin fold of the intima jutting out from the wall into the lumen » function to prevent the back flow of blood • Large veins – The tunica intima of large vein is similar to medium vein except the large veins have a thick subendothelial connective tissue layer Blood Vessel • Arteriovenous anastomoses – Terminal of most arteries end in capillary beds • which deliver their blood to venules for the return back to the venous side of the cardiovascular system – In many part of our body, however the artery simply joins with a venous channel forming an arteriovenous anastomoses (AVA) • useful in thermoregulation • found abundant in the skin • innervated with adrenergc and cholinergic nerves.
