Circulatory System II

1. Circulatory System II Blood Vessels Blood Composition Diseases and Abnormal Conditions

3. Blood Vessels • Closed system for the flow of blood from the heart to the rest of the body • Three (3) Main types of vessels • Arteries • Capillaries • Veins

4. Arteries • Carry blood away from heart • More muscular and elastic than other vessels (must withstand pressure from heart contraction) • Largest in body is the Aorta • First branch off the aorta is the coronary artery that supplies blood to the heart itself • Smallest branches are the Arterioles • Join capillaries that will lead to venules

5. Capillaries • Connect arterioles with venules • Are close to almost every cell in body • Have thin walls that are only one cell layer thick • Allows oxygen and nutrients to pass through to cells • Allow carbon dioxide and waste products to enter from the cells

6. Veins • Carry blood back to the heart • Have thinner walls and less muscle than arteries • Superior and inferior vena cava are the 2 largest veins in the body • Venules are smallest branches of veins • Join capillaries that articulate with arterioles

8. Artery Structure vs. Vein Structure Arteries Have more muscular layer of tissue and greater elasticity that helps pump blood out to the body Veins Much thinner muscular layer Gravity and movement of surrounding muscles help deliver blood back to heart Contain valves that prevent backwards flow

9. Artery Structure vs. Vein Structure ARTERIES-carry blood away from heart-oxygenated (except in the pulmonary artery) VEINS-carry blood back to heart-deoxygenated (except in the pulmonary vein) CAPILLARIES -one layer thick

10. Blood • Often called a tissue because it contains many kinds of cells • Average adult body contains approximately 4-6 quarts of blood • Transports oxygen, carbon dioxide, nutrients, metabolic waste products, heat and hormones. • Composition • Fluid portion is plasma • Solid elements are blood cells

11. Plasma • Fluid portion of blood • Contains approximately 90% water • Contains dissolved or suspended substances • Blood proteins (ex: fibrinogen, prothrombin) • Nutrients (vitamins, CHO, proteins) • Mineral salts or electrolytes (K, Ca, Na) • Gases(O2, CO2) • Metabolic waste products • Hormones • Enzymes

12. Blood Cells • Three main kinds • Erythrocytes (red blood cells) • Leukocytes (white blood cells) • Thrombocytes (platelets)

13. Erythrocytes • Produced in red bone marrow at rate of 1 million per minute • Live approximately 120 days, broken down by liver and spleen • 4.5-5.5 million per cc mm in blood (~ a drop of blood) • When mature, they lack a nucleus and are disk-shaped • Folic acid is required for the development of mature erythrocytes • Contains Hemoglobin – a complex protein molecule composed of the protein ‘globin’ and the iron compound called ‘heme’

14. Erythrocytes (cont.) • Hemoglobin • Carries both O2 and CO2 • When carrying O2, hemoglobin gives blood characteristic red color • Lots of O2= bright red • When carrying less O2 and more CO2, it is much darker with a bluish cast

15. Leukocytes • Formed in bone marrow and lymph tissue • Live about 3-9 days • Normal count is 5,000-9,000 per cc mm of blood • Can pass through capillaries and enter body tissue • Main function is to fight infection • Some cells do this by phagocytosis which is a process of engulfing, ingesting and destroying pathogens

16. 5 Types of Leukocytes • Neutrophils • Phagocytize bacteria by secreting the enzyme lysozyme • Eosinophils • Remove toxins and produce antihistamine to defend body from allergic reactions • Basophils • Participate in body’s inflammatory response • Produce histamine (a vasodilator) • Produce heparin (an anticoagulant)

17. 5 Types of Leukocytes (cont.) • Monocyte • Phagocytize bacteria and foreign materials • Lymphocytes • Develop antibodies to provide immunity for the body • Protect against formation of cancer cells

19. Thrombocytes • Fragments of cells • Contain no nucleus and varyin shape and size • Formed in bone marrow • Live for 5-9 days • Normal count is 250,000 to 400,000 per cc mm of blood • Important in clotting process

20. Clotting Process • Thrombocytes gather at site of cut to form a sticky plug • Cells secrete the chemical serotonin – causes vessel to spasm and narrow, decreasing flow of blood • Cells release an enzyme, thromboplastin, which acts with calcium to form thrombin • Thrombin acts on blood protein fibrinogen to form fibrin • Fibrin is a gel-like net of fibers that traps the erythrocytes, platelets and plasma to form a clot

21. Diseases and Abnormal Conditions • Anemia • Aneurysm • Arrhythmias • Arteriosclerosis • Atherosclerosis • Congestive Heart Failure • Embolus • Hemophilia • Hypertension • Leukemia • Myocardial Infarction • Phlebitis • Varicose Veins

22. Anemia • Inadequate number of red blood cells, hemoglobin, or both • Symptoms • Pallor (paleness) • Fatigue • Dyspnea (difficult breathing) • Tachycardia (rapid heart rate)

23. Types of Anemia • Acute blood loss anemia – from hemorrhage • Iron deficiency anemia - inadequate amount of iron • Aplastic anemia – destruction of bone marrow leading to poor formation of erythrocytes • Pernicious anemia – low number of abnormally large rbcs, resulting from lack of intrinsic factor (found in stomach) resulting in poor absorption of vitamin B12 (this and folic acid are necessary for development of mature rbcs • Sickle cell anemia – chronic inherited anemia with crescent-shaped erythrocytes that carry less O2, break easily and block blood vessels, almost found exclusively in African Americans

24. Aneurysm • Ballooning out of, or sac-like formation on, an artery wall • Some cause pain and pressure, others generate no symptoms • Common sites • Cerebral arteries • Aortal arteries • Abdominal arteries • If it ruptures, causes hemorrhage

25. Arrhythmias • Interference with normal electrical conduction pattern of the heart that causes abnormal heart rhythms • Can be mild to life-threatening • Examples: • Premature atrial contraction • Ventricular fibrillation • Life-threatening ones can be treated with a defibrillator – device that shocks heart to momentarily stop it and allows SA node to regain control • Pacemaker – battery-powered device that monitors heart and emits an electrical impulse to stimulate contraction

26. Arteriosclerosis • Hardening or thickening of arterial walls • Loss of elasticity and contractility • Commonly result of aging • Results in hypertension which can lead to aneurysm or cerebral hemorrhage • Treatment is to lower blood pressure through diet, medications, or both

27. Atherosclerosis • Depositing of fatty plaques on arterial walls • Narrows the opening in the blood vessel which reduces blood flow • Treatment • Low cholesterol diet • Medication to lower cholesterol • Abstaining from smoking • Reduction of stress • Exercise • Angioplasty – a procedure to remove or compress deposits in arteries, or to insert a stent to allow blood flow • Bypass surgery • Complication • Formation of embolus if plaques break loose and circulate in bloodstream

28. Congestive Heart Failure • Inadequate contraction of heart muscles to supply body with needed blood supply • Can involve right or left side of heart or both • Symptoms: • Edema (swelling) • Dyspnea (difficulty breathing) • Pallor or cyanosis • Distention of neck veins • Weak, rapid pulse • Cough accompanied by pink, frothy sputum

29. Congestive Heart Failure • Treatment methods: • Cardiotonic drugs – to slow and strengthen heart • Diuretics – to remove retained body fluids • Elastic support hose – to help veins return blood to heart • Oxygen therapy • Bed rest • Low-sodium diet

30. Embolus • Definition – a foreign substance circulating in the bloodstream • Air, blood clot, bacterial clumps, fat globule, other substances • Blockage of blood vessel can occur Hemophilia • An inherited disease, almost exclusively in males, where blood is not able to clot due to lack of a plasma protein required for the clotting process • Treatment – blood or plasma transfusion, and administering the missing protein factor

31. Hypertension • High blood pressure; considered with a systolic pressure > or = 140, or diastolic pressure > or = 90 • Risk factors include: important to know these • Family History - Race • Obesity - Stress • Smoking - Aging • Diet high in saturated fat • Treatment (no cure) • Controlled with diet, exercise, medications, change of habits • If not controlled, then damage to heart, blood vessels, and kidneys occurs

32. Leukemia • Malignant disease of the bone marrow or lymph tissue that results in a high number of immature white blood cells • Symptoms • Fever, pallor, swelling of lymphoid tissues, fatigue, anemia, bleeding of gums, excessive bruising, joint pain • Treatment • Chemotherapy • Radiation • Bone marrow transplant

33. Myocardial Infarction • “Heart attack” caused by blockage of coronary arteries that cut off blood supply to heart which causes affected heart tissue to die (“infarct”) • Death can occur immediately if large area is affected • Symptoms include: • Severe crushing chest pain (angina pectoris) • Pain that radiates to arm, neck and jaw • Pressure in chest • Perspiration, cold clammy skin • Dyspnea • Change in BP

34. Myocardial Infarction • If heart stops, start cardiopulmonary resuscitation (CPR) • Treatments: • Thrombolytic or “clot-busting” drugs within first few hours (not used if bleeding is present) which restores blood flow to the heart • Additional treatments • Complete bed rest • Medications: Vasodilators, Cardiotonic drugs, Anticoagulants • Oxygen therapy • Heart Attack video clip http://www.youtube.com/watch?v=H_VsHmoRQKk

35. Phlebitis • Inflammation of a vein • Usually in the leg • If a clot is also present, it’s called “thrombophlebitis” • Symptoms • Pain, edema, redness • Treatment • Anticoagulants • Pain medication • Elevation of affected leg • Support hose • Possible surgery to remove clot

36. Varicose Veins • Dilated swollen vein that lost elasticity that causes stasis or decreased blood flow • Frequently occurs in the legs • Results from pregnancy, prolonged sitting or standing, or genetic factors • Treatment: • Exercise • Support hose • Avoidance of prolonged sitting or standing or tight-fitting clothing • Possible surgery to remove vein

37. The END