1. THE CIRCULATORY SYSTEM THE HEART, BLOOD VESSELS, AND BLOOD

2. THE CLOSED CIRCULATORY SYSTEM Humans have a closed circulatory system, typical of all vertebrates, in which blood is confined to vessels and is distinct from the interstitial fluid. The heart pumps blood into large vessels that branch into smaller ones leading into the organs. Materials are exchanged by diffusion between the blood and the interstitial fluid bathing the cells.

3.  The circulatory system carries blood and dissolved substances to and from different places in the body.  The Heart has the job of pumping these things around the body.  The Heart pumps blood and substances around the body in tubes called blood vessels.  The Heart and blood vessels together make up the Circulatory System. WHAT IS THE CIRCULATORY SYSTEM?

4. THE CARDIOVASCULAR SYSTEM Three Major Elements – 1.Heart 2.Blood Vessels 3.Blood

5. 1. THE HEART The Heart highly interconnected cells cardiac muscle tissue four chambers Right atrium Right ventricle Left atrium Left ventricle

7. lungs head & arms liver digestive system kidneys legs pulmonary artery aorta pulmonary vein main vein LeftRight How does this system work? Circulatory System

8. Lungs Body cells Our circulatory system is a double circulatory system. This means it has two parts. the right side of the system deals with deoxygenated blood. the left side of the system deals with oxygenated blood.

9. THE HEART These are arteries. They carry blood away from the heart. This is a vein. It brings blood from the body, except the lungs. Coronary arteries, the hearts own blood supply The heart has four chambers 2 atria 2 ventricles now lets look inside the heart

10. The Heart Left Ventricle Left Atrium Right Atrium Right Ventricle valve Vein from Lungs Artery to Head and BodyArtery to Lungs Vein from Head and Body valve

11. HOW DOES THE HEART WORK? blood from the body blood from the lungs The heart beat begins when the heart muscles relax and blood flows into the atria. STEP ONE

12. The atria then contract and the valves open to allow blood into the ventricles. STEP TWO HOW DOES THE HEART WORK?

13. The valves close to stop blood flowing backwards. The ventricles contract forcing the blood to leave the heart. At the same time, the atria are relaxing and once again filling with blood. The cycle then repeats itself. STEP THREE HOW DOES THE HEART WORK?

14. BLOOD FROM THE HEART GETS AROUND THE BODY THROUGH BLOOD VESSELS There are 3 types of blood vessels a. ARTERY b. CAPILLARY c. VEIN

15. 2. BLOOD VESSELS Arteries  arterioles move away from the heart Elastic Fibers Circular Smooth Muscle Capillaries – where gas exchange takes place. One cell thick Serves the Respiratory System Veins  Venules moves towards the heart Skeletal Muscles contract to force blood back from legs One way values When they break - varicose veins form

17. The ARTERY thick muscle and elastic fibres Arteries carry blood away from the heart. the elastic fibres allow the artery to stretch under pressure the thick muscle can contract to push the blood along.

18. The VEIN Veins carry blood towards from the heart. thin muscle and elastic fibres veins have valves which act to stop the blood from going in the wrong direction. body muscles surround the veins so that when they contract to move the body, they also squeeze the veins and push the blood along the vessel.

19. The CAPILLARY Capillaries link Arteries with Veins the wall of a capillary is only one cell thick they exchange materials between the blood and other body cells. The exchange of materials between the blood and the body can only occur through capillaries.

20. arteryvein capillaries body cell The CAPILLARY capillary bed A collection of capillaries is known as a capillary bed.

21. WHAT’S IN BLOOD? red blood cells white blood cells platelets plasma carbon dioxide digested food waste (urea) hormones oxygen

22. 3. THE BLOOD A.Plasma - Liquid portion of the blood - Contains clotting factors, hormones, antibodies, dissolved gases, nutrients and waste

23. Plasma A straw- coloured liquid that carries the cells and the platelets which help blood clot. carbon dioxide glucose amino acids proteins minerals vitamins hormones waste materials like urea. It also contains useful things like;

24. B. Erythrocytes - Red Blood Cells - Carry hemoglobin and oxygen. Do not have a nucleus and live only about 120 days. -Can not repair themselves.

25. Red Blood Cells contain haemoglobin, a molecule specially designed to hold oxygen and carry it to cells that need it. can change shape to an amazing extent, without breaking, as it squeezes single file through the capillaries. a biconcave disc that is round and flat without a nucleus

26. C. Leukocytes – White Blood cells - Fight infection and are formed in the bone marrow - Five types: neutrophils, lymphocytes, eosinophils, basophils, and monocytes.

27. White Blood Cells there are many different types and all contain a big nucleus. the two main ones are the lymphocytes and the macrophages. some lymphocytes fight disease by making antibodies to destroy invaders by dissolving them. other lymphocytes make antitoxins to break down poisons. macrophages ‘eat’ and digest micro- organisms.

28. D. Thrombocytes – Platelets - These are cell fragment that are formed in the bone marrow from megakaryocytes. - Clot blood by sticking together – via protein fibers called fibrin.

29. Platelets Platelets are bits of cell broken off larger cells. Platelets produce tiny fibrinogen fibres to form a net. This net traps other blood cells to form a blood clot.

30. THE BLOOD plasma red blood cell white blood cell platelets

31. FUNCTIONS OF THE HEART Generating blood pressure Routing blood Heart separates pulmonary and systemic circulations Ensuring one-way blood flow Heart valves ensure one-way flow Regulating blood supply Changes in contraction rate and force match blood delivery to changing metabolic needs

32. SIZE, SHAPE, LOCATION OF THE HEART Size of a closed fist Shape Apex: Blunt rounded point of cone Base: Flat part at opposite of end of cone Located in thoracic cavity in mediastinum

33. HEART CROSS SECTION

34. PERICARDIUM

35. HEART WALL Three layers of tissue Epicardium: This serous membrane of smooth outer surface of heart Myocardium: Middle layer composed of cardiac muscle cell and responsibility for heart contracting Endocardium: Smooth inner surface of heart chambers

36. HEART WALL

37. EXTERNAL ANATOMY Four chambers 2 atria 2 ventricles Auricles Major veins Superior vena cava Pulmonary veins Major arteries Aorta Pulmonary trunk

38. CORONARY CIRCULATION

39. HEART VALVES Atrioventricular Tricuspid Bicuspid or mitral Semilunar Aortic Pulmonary Prevent blood from flowing back

40. HEART VALVES

41. FUNCTION OF THE HEART VALVES

42. BLOOD FLOW THROUGH HEART

43. SYSTEMIC AND PULMONARY CIRCULATION

44. HEART SKELETON Consists of plate of fibrous connective tissue between atria and ventricles Fibrous rings around valves to support Serves as electrical insulation between atria and ventricles Provides site for muscle attachment

45. CARDIAC MUSCLE Elongated, branching cells containing 1-2 centrally located nuclei Contains actin and myosin myofilaments Intercalated disks: Specialized cell-cell contacts Desmosomes hold cells together and gap junctions allow action potentials Electrically, cardiac muscle behaves as single unit

46. CONDUCTING SYSTEM OF HEART

47. CARDIAC ARRHYTHMIAS Tachycardia: Heart rate in excess of 100bpm Bradycardia: Heart rate less than 60 bpm Sinus arrhythmia: Heart rate varies 5% during respiratory cycle and up to 30% during deep respiration Premature atrial contractions: Occasional shortened intervals between one contraction and succeeding, frequently occurs in healthy people

48. ALTERATIONS IN ELECTROCARDIOGRAM

49. CARDIAC CYCLE Heart is two pumps that work together, right and left half Repetitive contraction (systole) and relaxation (diastole) of heart chambers Blood moves through circulatory system from areas of higher to lower pressure. Contraction of heart produces the pressure

50. CARDIAC CYCLE

51. HEART SOUNDS First heart sound or “lubb” Atrioventricular valves and surrounding fluid vibrations as valves close at beginning of ventricular systole Second heart sound or “dupp” Results from closure of aortic and pulmonary semilunar valves at beginning of ventricular diastole, lasts longer Third heart sound (occasional) Caused by turbulent blood flow into ventricles and detected near end of first one-third of diastole

52. LOCATION OF HEART VALVES

53. REGULATION OF THE HEART Intrinsic regulation: Results from normal functional characteristics, not on neural or hormonal regulation Starling’s law of the heart Extrinsic regulation: Involves neural and hormonal control Parasympathetic stimulation Supplied by vagus nerve, decreases heart rate, acetylcholine secreted Sympathetic stimulation Supplied by cardiac nerves, increases heart rate and force of contraction, epinephrine and norepinephrine released

54. HEART HOMEOSTASIS Effect of blood pressure Baroreceptors monitor blood pressure Effect of pH, carbon dioxide, oxygen Chemoreceptors monitor Effect of extracellular ion concentration Increase or decrease in extracellular K + decreases heart rate Effect of body temperature Heart rate increases when body temperature increases, heart rate decreases when body temperature decreases

55. BARORECEPTOR AND CHEMORECEPTOR REFLEXES

56. BARORECEPTOR REFLEX

57. CHEMORECEPTOR REFLEX-PH

58. EFFECTS OF AGING ON THE HEART Gradual changes in heart function, minor under resting condition, more significant during exercise Hypertrophy of left ventricle Maximum heart rate decreases Increased tendency for valves to function abnormally and arrhythmias to occur Increased oxygen consumption required to pump same amount of blood

59. DISORDERS OF THE CIRCULATORY SYSTEM Anemia - lack of iron in the blood, low RBC count Leukemia - white blood cells proliferate wildly, causing anemia Hemophilia - bleeder’s disease, due to lack of fibrinogen in thrombocytes Heart Murmur - abnormal heart beat, caused by valve problems Heart attack - blood vessels around the heart become blocked with plaque, also called myocardial infarction