The Circulatory System

1. Chapter 16 The Circulatory System

2. Four Main Parts of the Circulatory System • Heart • Acts like a pump • Blood vessels • Act like the plumbing • Blood • Circulating fluid • Lymphatic system • Acts to provide auxiliary fluid

3. The Anatomy of the Heart • Located behind the sternum and in between the lungs • Two-thirds of the heart is on the left side of the chest. • The heart is about the size of a clenched fist.

4. The External Heart Structures

5. The Internal Heart Structures

6. The Heart Sounds • Lub • First sound • Caused by the valves slamming shut between the atria and ventricles • Dub • Second sound • Caused by the closure of the semilunar valves closing in the aorta and pulmonary arteries

7. The Pacemaker of the Heart • Sinoatrial (SA) node or “pacemaker” - a specialized group of nerve cells located in the right atrium • This node generates the electrical impulse that starts each wave of muscle contraction in the heart.

8. Artificial Pacemaker with Atrial and Ventricular Leads

9. Nerves Influencing the Heart Rate

10. The Blood Vessels • Arteries • Vessels throughout the body that expand and contract as they carry fresh, oxygenated blood away from the heart • The only exception is the pulmonary artery, which carries deoxygenated blood to the lungs. • Arterioles • Connect arteries to capillaries

11. Major Arteries of the Body

12. The Blood Vessels • Capillaries • Oxygen-rich blood enters the capillary bed, where the exchange of gasses occurs. • When blood leaves the capillary bed, it carries away carbon dioxide and waste. • Capillary beds reduce the rate of blood flow and allow oxygen and nutrients to enter the tissue cells in exchange for carbon dioxide and waste.

13. The Blood Vessels • Veins • Similar to arteries, but the walls are thinner and they lack elastic fibers • Veins carry deoxygenated blood back to the heart. • Exception: The pulmonary veins return oxygenated blood from the lungs to the heart.

14. Major Veins of the Body

15. The Blood Vessels • Venules • Join together with the capillaries to form veins that eventually enter the heart through the vena cava

16. The Pathway of Blood through the Systemic Circulation 1. Blood leaves the left ventricle and enters the aorta. 2. As the aorta descends through the body, the thoracic and abdominal portions give origin to the arteries supplying the organs of the thorax and abdomen. 3. The aorta divides at the fourth lumbar vertebra into two large common iliac arteries.

17. The Pathway of Blood through the Systemic Circulation 4. The external branch of the iliac artery becomes the femoral artery and continues down the leg as the tibial branch. 5. All systemic arteries subdivide until they become arterioles and join the capillaries. 6. Upon leaving the capillaries, blood is considered deoxygenated. The capillaries join venules, which eventually become veins.

18. The Pathway of Blood through the Systemic Circulation 7. The major veins of the lower extremities join with pelvic veins and enter the inferior vena cava. 8. The major veins of the upper extremities join with the subclavian, internal and external jugular, the innominate, and the sinuses from the head to enter the superior vena cava.

19. The Pathway of Blood through the Systemic Circulation • The superior and inferior vena cava empty into the right atrium of the heart.

20. Portal Circulation

21. Portal Circulation 1. Arteries branch off the aorta as it descends to the internal organs. 2. Each organ then receives the substances on which it reacts. 3. These substances can be sugar, salt, hormones, chemicals, nutrients, or waste. 4. Everything you eat, drink, inhale, or inject enters the circulatory system.

22. The Structure of the Lymphatic System • Lymph nodes • Lymph (a straw-colored fluid) • Lymph vessels • Spleen • Lymph tissue • Tonsils • Thymus gland

23. The Components of Whole Blood and Their Roles

24. The Components of Whole Blood and Their Roles • Red blood cells (RBCs) • Erythrocytes • Contain hemoglobin which gives blood its red color • Hemoglobin attracts and carries oxygen and carbon dioxide in the blood. • Erythrocytes live about 4 months

25. The Components of Whole Blood and Their Roles • White blood cells (WBCs) • Called leukocytes • Leukocytes play a vital role in defending the body against invasion by chasing down bacteria. • Leukocytes divide into granulocytes and agranulocytes

26. The Components of Whole Blood and Their Roles • Granulocytes are white blood cells produced in the red bone marrow. • There are three types: • Neutrophils • Eosinophils • Basophils

27. The Components of Whole Blood and Their Roles • Neutrophils • Surround, swallow, and digest bacteria • Eosinophils • Respond to allergic reactions or parasites • Basophils • Respond to chronic infection

28. The Components of Whole Blood and Their Roles • Agranulocytes • White blood cells produced by bone marrow and lymph tissue that break down into two types: • Lymphocytes produce immunity by developing antibodies and attaching to and destroying foreign bodies. • Monocytes eat and destroy bacteria.

29. The Components of Whole Blood and Their Roles • Platelets • Thrombocytes • Smallest of the three cells • Formed in the bone marrow from cell fragments • Platelets function in the process of clotting blood

30. The Clotting Process 1. The cut vessel attracts or catches platelets. 2. Platelets form a small mass at the cut. 3. Platelets release a chemical that causes the vessel to narrow and decreases blood loss until a clot forms.

31. The Clotting Process • Platelets and the injured tissue release thromboplastin, which begins to create a reaction that forms a network of fine mesh fibers over the cut. • This net catches the red blood cells, platelets, and plasma and forms the clot.

32. Blood Types and Their Importance • Blood types are determined by the presence of a protein factor, called an antigen, on the surface of the red blood cell. • There are four types of blood: • A • B • AB • O

33. Blood Types and Their Importance • Blood plasma also has a protein substance, called an antibody, that reacts to the protein on the surface of the blood cell. • Blood clumps and forms clots if antigens and antibodies of the same type come together. • During blood transfusions, determining the blood type can prevent this reaction.

34. The Importance of the Rh Factor • Originally detected in, and named after, the Rhesus monkey • An antigen that may or may not be present in the red blood cell • If a person without the antigen receives blood with the antigen, the body produces antibodies that can cause serious complications.

35. Arteriography • X-ray examination of the arteries after injection of a contrast medium • This test indicates the status of blood flow, aneurysms, or the presence of hemorrhage.

36. Cardiac Catheterization • A catheter is inserted into the brachial or femoral artery and is passed up into the heart. • A contrast medium is injected into the catheter to permit visualization of the heart chambers, valves, and pulmonary and coronary arteries.

37. Doppler Ultrasonography • Sound waves are transmitted through the skin and are reflected by blood cells moving through the blood vessels. • This test evaluates blood vessels and can diagnose deep vein thrombosis, aneurysms, and arterial blockages.

38. Echocardiogram • Uses high-frequency sound waves to make images of the internal heart structures • Evaluates cardiac function, the condition of the heart valves, defects in the heart walls, and the presence of fluid between layers of the pericardium

39. Electrocardiograph • Abbreviated EKG or ECG • Provides a graphic recording of the electrical activity of the heart • Identifies heart rhythms and provides a method of detecting the progression of cardiac disease

40. Holter Monitor • An ambulatory ECG that records heart activity over a 24-hour period • This test helps to evaluate symptoms that occur irregularly. • This test can also evaluate the status of recovering cardiac patients.

41. Heart Scan • Computerized CT scan that sweeps electron beams so fast that it freezes the beating motion of the heart • Diagnoses the presence of plaque and coronary occlusion

42. MUGA Scan • Multiple-gated acquisition scan • After isotopes are injected into the vein and taken up by the myocardium, a camera records the motion of the heart. • This test evaluates the condition of the myocardium.

43. Myocardial Perfusion Imaging • This test measures the passage of blood through the coronary arteries to the myocardium. • The blood vessels are dilated and a radioactive material is injected. • This material concentrates in the areas of the myocardium with good blood flow.

44. Venogram • X-ray studies using a contrast medium to determine the condition of the deep veins of the legs

45. Anemia • Term used to indicate elements that are lacking in the blood • Iron-deficiency anemia • Lack of iron • Aplastic anemia • Injury or destruction of blood cell formation by the bone marrow

46. Anemia • Blood loss anemia • Condition of low red blood cell count occurring over an extended period of time

47. Aneurysm • Ballooning out of the wall of an artery • Often associated with atherosclerosis or arteriosclerosis • Cerebral aneurysms • Occur in the brain

48. Aneurysm • Thoracic aneurysms • Occur in the chest • Abdominal aneurysms • Occur in the abdomen

49. Angina • Severe chest pain that radiates down the inner surface of the left arm • Usually associated with emotional stress or physical exertion • May last from a few seconds to several minutes

50. Cardiac Arrest • Complete, sudden cessation of heart action • Rapidly fatal • Produces brain damage after 5 minutes