Unit3 nutritionalprocesscirculatory
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  • 1. Unit 3.C. The circulatory system
  • 2. Index Composition of the Circulatory System 2. Blood Circulation 3. The Working of the Heart 4. Some Illnesses of the Circulatory System 1.
  • 3. 1. Composition of the Circulatory System The human circulatory system consists of: 1.1 Blood vessels 1.2 Heart 1.3 Blood
  • 4. 1.1 Blood Vessels
  • 5. Caracteristics of Blood Vessels Arteries have thick walls,  no valves and  carry blood away from the heart  Capillaries   link arteries to veins. Their wall is only one cell thick and this allows substances to pass into and out of the blood. Veins • have thin walls, • valves, and • carry blood to the heart http://www.youtube.com/watch?v=CjNKbL_-cwA  Types of blood vessels
  • 6. 1.2 Parts of the Heart    It is a pump that pushes the blood into the arteries. Is made of cardiac muscle, a special kind of muscle that never tires. Is divided into two sides by a wall called the septum.
  • 7. It has got four chambers:  Atria: the two upper chambers (singular: atrium). They have thin walls. They pump blood to the ventricles.  Ventricles: the two lower chambers. They pump blood out of the heart.  right ventricle, with thin wall, pumps the blood to the lungs .  left ventricle, with thicker and stronger wall, pumps the blood to the body.
  • 8. Valves Tricuspid valve and bicuspid valve or mitral valve, between atria and ventricles. Semilunar valves (aortic valve and pulmonary valve) between ventricles and arteries. Valves prevent the backflow of blood. http://vimeo.com/5588613 ==> valves working
  • 9. THE HEART
  • 10. http://www.youtube.com/watch?v=jLTdgrhpDCg  Cardiac Cycle, systole and diastole
  • 11. 1.3 The Blood Every person has 4 to 5 litres of blood on average.  55% of the blood is plasma  45% consists of blood cells and platelets. (leukocytes)  They defend the body from infection  coagulation (erythrocytes)
  • 12. Composition of Blood http://www.youtube.com/watch?v=CRh_dAzXuoU  blood cells
  • 13. FUNCTIONS OF THE BLOOD  Transport of:     Nutrients Waste products Hormones Oxygen and carbon dioxide  Keeping the normal temperature of the body  Defence against disease
  • 14. 2. Blood circulation Blood circulation in human being is double and complete It has two circuits (general and pulmonary) The blood in the veins never mixes with the blood in the arteries
  • 15. 3. The working of the heart
  • 16. The movement of blood through the heart 1. Blood from the body enters the right atrium through the vena cava. The atria contract, the blood is pushed through the tricuspid valve, into the right ventricle. 2. When the right ventricle contracts, the blood is pumped through the semilunar valve into the pulmonary arteries. 3. Blood goes to the lungs. In the lungs, the blood collects up oxygen and gets rid of its carbon dioxide. 4. It then comes back to the heart in the pulmonary vein which enters the left atrium. When the atria contract, the blood is pushed through the bicuspid o mitral valve into the left ventricle. 5. The ventricles contract and this pushes the blood through the semilunar valve to the main artery of the body, aorta. 6. Blood is pushed out to all around the body.
  • 17. The stages of heartbeat (cardiac cycle)   Diastole: heart chambers relax. Systole: heart chambers contract.
  • 18. Heartbeat
  • 19. http://www.youtube.com/watch?v=jLTdgrhpDCg
  • 20. 4. Some illnesses of the circulatory system Arteriosclerosis Accumulation of substances (fats, calcium…) in the arteries, which causes them to narrow and restricts the blood flow. http://www.youtube.com/watch?v=qRK7-DCDKEA  atherosclerosis (a common form of arteriosclerosis in which fatty substances form a deposit of plaque on the inner lining ofarterial walls)
  • 21. Thrombosis Blood clots formed in a blood vessel. It is especially dangerous in the brain or in the heart http://www.youtube.com/watch?v=OxY4BphpGqo  Thrombosis
  • 22. Heart attack and angina Arteries which carry blood to the cardiac cells Angina: narrowing or partial obstruction of the coronary arteries. Heart attack: total obstruction of the coronary arteries