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Vascular System - Coggle Diagram
Vascular System
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Pulmonary Circulation - deoxygenated blood from the heart to the lungs and oxygenated blood back to the heart.
Systemic Circulation - Oxygenated blood from the heart to the body and deoxygenated blood from the body to the heart.
Blood Vessels
Arteries - carry blood away from the heart. Thick, strong, contain muscles, elastic fibres and fibrous tissue. Narrow Lumen. Strength and elasticity needed to with stand pulsing of blood. Helps maintain high blood pressure, preventing backflow.
Capillaries - supply cells with all of their requirements, take away waste products. Very thin - only one cell thick. Very narrow lumen, just enough for one red blood cell. No need for strong walls as most blood pressure has been lost. Thin walls and narrow lumen allow for diffusion. White blood cells can squeeze between walls.
Veins - return blood back to the heart at low pressure. Thin mainly fibrous tissue, contain far less muscle and elastic tissue than arteries. Wide lumen. Valves to prevent backflow. No need for strong walls as most of the blood pressure has been lost. Wide lumen offers less resistance to blood flow.
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Venous return mechanisms
Skeletal muscle pump – increased contraction of muscles press nearby veins (to squeeze blood back to the heart)
Respiratory pump – increased breathing rate will alter/change pressure in thoracic cavities/area to (assist blood flow back to the heart)
Suction pump of heart – more blood pumped out of the heart, so more blood then drawn/forced back
Pocket valves – (located in veins), stop backflow (by closing) and help shunt blood back to heart
Smooth muscle – located in the walls of the veins/involuntary muscle contraction (help to squeeze blood back to heart)
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