Heart 0.0 / 5 ? BiologyHeartASEdexcel Created by: LottieCCreated on: 31-03-14 15:42 Transport System Carry raw materials from specialised exchange organs to body cells & remove waste Too big to effictively carry out diffusion 1 of 9 How is the heart adapted? Left Ventricle is thicker because it needs to contract strongly to pump blood all around the body - right side only pumps blood to the lungs Ventricles have thicker walls than the atria - push blood out the heart Atrioventricular valves prevent backflow into atria when ventricles contact Semi-Lunar Valve prevent backflow inot heart after ventricls contract 2 of 9 Valves Valves only open one way - deependent on pressure High pressure behind valve = open High pressure in front of valve = closed 3 of 9 Arteries Carry oxygenated blood away from the heart at high pressure Narrow Lumen Thick walled - muscular, collagen & elsatic tissue to cope with high pressure Endothelium folded- artery can expand = cope with high pressure No valves 4 of 9 Veins Veins take deoxygenated blood to th heart at low pressure Wide Lumen Thin walls - little elastic or muscle tissue Valves - prevent backflow 5 of 9 Capillaries Very narrow lumen One cell thick wall - speeds up diffusion with substances Network of capillaries = capillary bed 6 of 9 Ventricular Diastole - Atrial Systole Ventricles are relaxd Atria contracts - decerasing volume in chamber & increasing pressure Pushes blood into ventricles Increase in ventricular pressure & volume as thy receive ejected blood from atria 7 of 9 Ventricular Systole - Atrial Diastole Atria relax Ventricles contact - increases presuure Atrioventricular valves shut - pressure difference Semilunar valves forced open & blood forced into artries 8 of 9 Diastole Venticles & Atria both relax High pressure in aorta & pulmonary artery closes SL vavle Blood returns to heart & atria fills again As ventricles relax - pressure dcreases = AV valves open Blood freely flows into ventricles 9 of 9
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