The heart

• 1. By Likhila abraham

2. Location The heart is located in the thoracic cavity Posterior to the sternum Superior to the diaphragm Between the lungs The tip of the heart is called the apex Image source See slide 28 3. FOUR CHAMBERS OF THE HEART Right Atrium Left Atrium Right Ventricle Left Ventricle 4. Arteries and Veins Superior Vena Cava Pulmonary Veins Inferior Vena Cava Aorta Left Pulmonary Artery Pulmonary Veins 5. Right Atrium Receives de-oxygenated blood from the superior vena cava and pumps it into the right ventricle. Right Atrium Right Ventricle (Heart) 6. Right Ventricle Receives de-oxygenated blood from the right atrium and pumps it into the pulmonary artery. Right Ventricle Pulmonary artery 7. Left Atrium Is larger than the right atrium, it receives oxygenated blood from the pulmonary veins, and pumps it into the left ventricle. Left Atrium Left Ventricle 8. Left Ventricle Is larger then the right ventricle, it receives oxygenated blood from the left atrium, and pumps it into the aorta. Left Ventricle Aorta 9. Aorta Is the largest artery in the human body, it receives oxygenated blood from the left ventricle of the heart and moves it to all parts of the body. Aorta 10. Pulmonary Veins Carry oxygenated blood from the lungs to the left atrium of the heart. Fact: They are the only veins that carry oxygenated blood. Pulmonary Veins Pulmonary Veins 11. Inferior Vena Cava Is the large vein that carries de-oxygenated blood from the lower half of the body into the heart. Inferior Vena Cava 12. Superior Vena Cava Is a large but short vein that carries de- oxygenated blood from the upper half of the body to the hearts right atrium. Superior Vena Cava 13. Valves of the heartThe valves are located within the chambers of the heart. The function of the valves: Controls the direction of blood flow Allows one way flow of blood - through chambers - from the heart to the body Image source See slide 28 Valves of heart 14. The four valves are known as: the tricuspid valve the pulmonic or pulmonary valve the mitral valve the aortic valve 15. The tricuspid valve: Is an atrioventricular valve, situated between the atria and the ventricle Controls the opening between the right atrium and the right ventricle 16. The mitral valve: Is an atrioventricular valve, situated between the atria and the ventricle Controls the blood between the left atrium and the left ventricle 17. The pulmonic or pulmonary valve: Is a semi lunar valve which controls the blood leaving the heart Situated between the right ventricle and the pulmonary valve Controls the flow of blood from the right ventricle Prevents blood flow back to the right ventricle, as it 18. Pulmonary circulation and the heart The inferior and superior vena cava carry oxygen depleted blood to the relaxed right atrium of the heart The right atrium contracts and blood travels through the tricuspid valve into the relaxed right ventricle The right ventricle contracts, the blood is pumped through the pulmonary valve into the pulmonary artery to the lungs Gas exchange occurs in the lungs Co2 is released and oxygen is absorbed The oxygen rich blood then travels via the pulmonary veins to the left atrium 19. Systemic circulation and the heart Oxygen rich blood travels from the lungs via the pulmonary veins to the left atrium The left atrium contracts, and blood flows through the mitral valve into the relaxed left ventricle The strong left ventricle contracts and pumps oxygen rich blood through the aortic valve into the aorta 20. Conduction system of heart 21. Cardiac conduction is: the rate the heart conducts electrical impulses The electrical pulses determine the order in which the chambers contract: the heart rate The path the impulses travel: Sinoatrial node (SA node) Atrioventricular node (AV node) Bundle branches Purkinge fibres 22. The Sinoatrial node (SA) : Is also known as the pace maker of the heart The Sinoatrial node is: Located in the upper wall of the right atrium Made up of nodal tissue - both muscle and nervous tissue Where the electrical impulse begins When the SA node contracts: Nerve impulses travel through the heart wall Both atria contract 23. The Atrioventricular (AV) node: Is located between the atria and ventricles of the heart Made up of nodal tissue The electrical impulse is carried from the SA node, and the AV node is stimulated. The AV node delays the path of the impulse, long enough for the atria to contract and empty 24. Atrioventricular bundle branches: are located between the atria and the ventricles. Fibres branch into two bundles -left and right side of the heart The electrical impulse travels from the AV node to the bundle branches after the atria have contracted and emptied. The AV bundle branches then carry the impulses down the centre of the heart to the left and right 25. The AV bundles start to divide further into: Purkinje fibres Purkinje fibres: Located at the end of the AV bundle branches, at the base of the heart The Purkinje fibres are responsible for the contraction of the ventricles 26. Thank you