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A+ BIOLOGY-IX, , STD-9-BIOLOGY-FIRST BELL-CLASS-14, Chapter – 3, , Simple Nutrients into cells, Blood Circulatory system,  Circulatory system in higher organisms consists of the heart, blood vessels and the blood., , Heart, Structure,  Heart is an organ that is completely made up of muscles.,  The heart works continuously like a pump and makes blood reach all the parts of the body., Location of the heart,  The heart is situated slightly tilted towards left in between the two lungs behind the sternum in the, thoracic cavity.,  The size of one's heart is equal to the size of fist., Covering of the heart, Pericardium: A double membrane called pericardium covers the heart.,  Pericardial fluid: The fluid between the two layers of pericardium.,  Function of pericardial fluid: Helps to reduce friction between the membranes when the heart, beats., Protection of the heart,  Heart is placed inside the ribcage.,  The heart has a covering of double membrane called pericardium.,  The pericardial fluid between the membranes protects the heart from shocks., Longitudinal section of heart, , A+ BLOG-www.apluseducare.blogspot.com 9072708051, , Page 1

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A+ BIOLOGY-IX, Heart and related blood vessels,  Aorta and Pulmonary artery: Vessels that carry blood from the heart,  The venacavae and pulmonary veins: Vessels that bring blood to heart, Chambers of the heart,  Right atrium, left atrium,,  Right ventricle, left ventricle., The blood vessels which carry blood to the heart and the heart chambers where they end,  Superior vena cava - Reaches the right atrium.,  Inferior vena cava - Reaches the right atrium.,  Pulmonary vein - Reaches the left atrium, The blood vessels which carry blood from the heart and the heart chambers from where they begin,  Aorta - From the left ventricle,  Pulmonary artery - From the right ventricle, Valves - Position - Function, Valve, Position, Function, Bicuspid valve, Between left atrium and left ventricle  Allows blood to flow from the left, atrium to the left ventricle.,  Prevents the blood from flowing back, when the ventricle contracts., Tricuspid valve, Between the right atrium and the right  Allows blood to the right ventricle., ventricle.,  Prevents the back ward flow of blood, when the ventricle contracts., Pulmonary valve At the beginning of pulmonary artery  Allows blood to flow from the right, ventricle to the pulmonary artery.,  Prevents the backward flow of blood, from the pulmonary artery to the right, ventricle., Aortic valve, At the beginning of the aorta,  Allows blood to flow from the left, ventricle to the aorta.,  Prevents the backward flow of blood, from the aorta to the left ventricle, Prepared by:, , Riyas, HST NS, PPMHSS Kottukkara, Kondotty-Malappuram, 9747944422, , More Resources, Visit https://apluseducare.blogspot.com/, Telegram Group: https://t.me/joinchat/ELv60hbE_g9Hvimlp0s1BA, , A+ BLOG-www.apluseducare.blogspot.com 9072708051, , Page 2