The Windkissel effect is seen in

The Windkissel effect is seen in large elastic vessels. The aoa, the pulmonary aery, and their major branches have a large amount of elastin in their walls. Hence, they have a high elastic recoil effect. This propey of elastic recoil is called windkessel effect (windkessel is a German for the elastic reservoir) This recoil of the vessels that have been stretched during systole helps to propel the blood forward during diastole thus maintaining a continuous flow throughout the cardiac cycle. Types Features Windkessel Aoa and large aeries Abundant elastic tissues in the inner and external elastic lamina Shows elastic recoil (Windkessel effect) when stretched Resistance Vessels Aerioles Have a less elastic tissue and lot of smooth muscle (maximum wall thickness to lumen ratio) Major site of resistanceto blood flow Exchange Vessels Capillaries Donot have smooth muscles, consist of single layer of endothelial cells surrounded by a basement membrane. Site exchange of nutrients,, water and gases. Types Continuous -brain, retina (have tight junctions) Fenestrated-glomeruli, choroid plexus Sinusoidal-liver,spleen Blood flow regulation is by contraction and relaxation of the aerioles and precapillary sphincter. Capacitance Vessels Venules and veins Thin-walled , easily distensible (maximum percentage of blood volume) Shunt Vessels AV anastomoses Have thick muscular walls with rich innervation Found in- finger tips, ear lobes Ref: Berne and Levy Physiology 7th edition Pgno: 351