UNIT B Chapter 10 Circulatory System and Lymphatic

UNIT B Chapter 10: Circulatory System and Lymphatic System Section 10. 8 Circulatory System Disorders Circulatory system disorders are also known as cardiovascular disease (CVD). CVD is the leading cause of death in most Western countries Examples of CVD include: • Atherosclerosis • Hypertension • Heart Valve Disease • Stroke, Heart Attack, and Aneurysm TO PREVIOUS SLIDE

UNIT B Chapter 10: Circulatory System and Lymphatic System Section 10. 8 Atherosclerosis Figure 10 B Coronary arteries and plaque. Atherosclerotic plaque is an irregular accumulation of cholesterol and fat. When plaque is present in a coronary artery, a heart attack is more likely to occur because of restricted blood flow. TO PREVIOUS SLIDE

UNIT B Chapter 10: Circulatory System and Lymphatic System Section 10. 8 Atherosclerosis • accumulation of soft masses of fatty materials (e. g. , cholesterol) beneath the inner linings of arteries. • Deposits of these materials are called plaque • Plaque narrows arteries by protruding into the blood vessel; this results in restricted blood flow • Plaque can also cause platelets to adhere to the arterial wall, forming a clot o If the clot remains stationary, it is called a thrombus o If the clot dislodges, it is called an embolus o Thromboembolism is a clot that has been carried in the blood and has become lodged in a blood vessel TO PREVIOUS SLIDE

UNIT B Chapter 10: Circulatory System and Lymphatic System Section 10. 8 Hypertension is high blood pressure. • Under the age of 45 years, blood pressure above 130/90 mm Hg is considered abnormally high • Called “the silent killer” because it may not be detected until a stroke or heart attack occurs • Occurs secondary to a narrowing of arteries due to atherosclerosis o Narrowed arteries cause an increase in blood pressure, since more force is needed to move blood through the blood vessels • Treatment involves vasodilators (which dilate blood vessels) and diuretics (which decrease blood volume by increasing TO PREVIOUS SLIDE urine)

UNIT B Chapter 10: Circulatory System and Lymphatic System Section 10. 8 Heart Valve Disease Heart valve disorders result in the backflow of blood, and range from mild to severe. • Heart valves can be malformed at birth, or they can degenerate due to age or infections • Result from narrowing (stenosis) of the aortic valve opening, or from mitral valve prolapse (abnormally thickened leaflets of the mitral valve protrude into the left ventricle) • Treatment involves repair of faulty valves in open-heart surgery or replacement with artificial valves or valves from an animal or deceased human TO PREVIOUS SLIDE

UNIT B Chapter 10: Circulatory System and Lymphatic System Section 10. 8 Stroke, Heart Attack, Aneurysm Stroke • Occurs when an arteriole in the brain bursts or is blocked by an embolus (a clot that has been dislodged) • Results in lack of oxygen (due to impaired blood flow) to the brain, causing a portion of the brain to die • Paralysis or death can result • Symptoms of stroke include numbness in the hands or face, difficulty speaking, or temporary blindness TO PREVIOUS SLIDE

UNIT B Chapter 10: Circulatory System and Lymphatic System Section 10. 8 Heart Attack • When a coronary artery becomes partially blocked, angina pectoris occurs, resulting in a squeezing or burning sensation in the chest • When a coronary artery is completely blocked, a portion of the heart muscle dies due to lack of oxygen, and a heart attack (myocardial infarction) occurs • Treatment includes vasodilators (nitroglycerin) to dilate blood vessels TO PREVIOUS SLIDE

UNIT B Chapter 10: Circulatory System and Lymphatic System Section 10. 8 Aneurysm • Occurs when there is a ballooning of a blood vessel, most often the abdominal aorta or the arteries leading to the brain • Atherosclerosis and hypertension can weaken the wall of the artery to the point that an aneurysm develops • If the aorta bursts, about 50% of victims die before reaching the hospital • Treatment involves replacing the damaged or diseased portion of the vessel with a synthetic graft TO PREVIOUS SLIDE

UNIT B Chapter 10: Circulatory System and Lymphatic System Section 10. 8 Treatment for Cardiovascular Disorders Coronary Bypass Operations • Involves grafting arteries to bypass an obstructed coronary artery • A segment from another blood vessel in the body is stitched to one end of the aorta; the other end is stitched to a coronary artery past the point of obstruction TO PREVIOUS SLIDE Figure 10. 26 Bypassing blocked coronary arteries. This is a 3 -D scan of the heart of a patient who received a triple bypass operation. The surgeon has bypassed two blocked arteries using vessels removed from another part of the body and used an existing artery that branches off the left subclavian artery to bypass a third blocked artery.

UNIT B Chapter 10: Circulatory System and Lymphatic System Section 10. 8 Stem Cells • Stem cells may be used to regenerate heart muscle that has been damaged by a heart attack • Stem cells injected directly into the damaged heart muscle of mice and rats differentiated into new heart muscle cells and new blood vessels • A “bioartificial” human heart has been grown by a research group by using cardiac muscle cells from a cadaver as a “scaffold” for human stem cells TO PREVIOUS SLIDE

UNIT B Chapter 10: Circulatory System and Lymphatic System Section 10. 8 Clearing Clogged Arteries • Angioplasty involves inserting a catheter into a clogged artery. o When the catheter reaches the site of the clogged artery, a balloon is inflated to force the vessel open • A stent is a metal mesh tube that inflates, expands, and locks the balloon into place. o Some stents are coated with medications that inhibit inflammation and scar formation TO PREVIOUS SLIDE Figure 10. 27 Angioplasty with stent placement. a. A plastic tube (catheter) is inserted into the coronary artery until it reaches the clogged area. b. A metal stent with a balloon inside it is pushed out the end of the plastic tube into the clogged area. c. When the balloon is inflated, the vessel opens, and the stent is left in place to keep the vessel open.

UNIT B Chapter 10: Circulatory System and Lymphatic System Section 10. 8 Dissolving Blood Clots • Thromboembolisms can be treated with tissue plasminogen activator (t. PA) o Converts plasminogen to plasmin, an enzyme that dissolves blood clots • Aspirin can be prescribed for individuals with symptoms of angina or stroke o Reduces stickiness of platelets and lowers the probability of clot formation TO PREVIOUS SLIDE

UNIT B Chapter 10: Circulatory System and Lymphatic System Section 10. 8 Heart Transplants and Artificial Hearts Heart transplants • The need for hearts to transplant is greater than the supply • A left ventricular assist device (LVAD) can be implanted in the abdomen of patients waiting for an implant o A tube passes blood from the left ventricle to the LVAD, which pumps it into the aorta TO PREVIOUS SLIDE Figure 10. 28 Human Heart. This human heart being cradled in the hands of a surgeon is about to be transplanted into a person whose own heart no longer functions properly.

UNIT B Chapter 10: Circulatory System and Lymphatic System Section 10. 8 Heart Transplants and Artificial Hearts Artificial hearts • A total artificial heart (e. g. , Abio. Cor) contains: o An internal battery o A controller (regulates pumping speed) o An external battery (powers the device by passing electricity through the skin) • A pump moves silicon hydraulic fluid between the left and right sacs to force blood out of the heart and into the pulmonary trunk and aorta TO PREVIOUS SLIDE Figure 10. 29 A total artificial heart. The Abio. Cor replacement heart is designed to be implanted within the chest cavity.