UNIT B: Human Body Systems Chapter 8: Human Organization Chapter 9: Digestive System Chapter 10: Circulatory System and Lymphatic System: Section 10.8 Chapter 11: Respiratory System Chapter 12: Nervous System Chapter 13: Urinary System Chapter 14: Reproductive System

Chapter 10: Circulatory System and Lymphatic System In this chapter, you will learn about the structure and function of the circulatory system and lymphatic system. UNIT B Chapter 10: Circulatory System and Lymphatic System TO PREVIOUS SLIDE What is the composition of blood, including blood cells? What organs and structures control the flow of blood throughout the body? In 2013, Lance Armstrong confessed to long-term blood doping and the use of banned substances. Blood doping involves artificially boosting the blood’s ability to bring more oxygen to muscles. Aerobic capacity and endurance improve where there are additional red blood cells available to carry oxygen.

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 UNIT B TO PREVIOUS SLIDE Section 10.8 Chapter 10: Circulatory System and Lymphatic System

Atherosclerosis is the 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 UNIT B TO PREVIOUS SLIDE Section 10.8 Chapter 10: Circulatory System and Lymphatic System Atherosclerosis

UNIT B TO PREVIOUS SLIDE Section 10.8 Chapter 10: Circulatory System and Lymphatic System Figure 10B 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.

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 urine) UNIT B TO PREVIOUS SLIDE Section 10.8 Chapter 10: Circulatory System and Lymphatic System Hypertension

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 UNIT B TO PREVIOUS SLIDE Section 10.8 Chapter 10: Circulatory System and Lymphatic System Heart Valve Disease

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 UNIT B TO PREVIOUS SLIDE Section 10.8 Chapter 10: Circulatory System and Lymphatic System Stroke, Heart Attack, Aneurysm

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 UNIT B TO PREVIOUS SLIDE Section 10.8 Chapter 10: Circulatory System and Lymphatic System

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 UNIT B TO PREVIOUS SLIDE Section 10.8 Chapter 10: Circulatory System and Lymphatic System

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 UNIT B TO PREVIOUS SLIDE Section 10.8 Chapter 10: Circulatory System and Lymphatic System Treatment for Cardiovascular Disorders Figure 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.

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 UNIT B TO PREVIOUS SLIDE Section 10.8 Chapter 10: Circulatory System and Lymphatic System

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 UNIT B TO PREVIOUS SLIDE Section 10.8 Chapter 10: Circulatory System and Lymphatic System Figure 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.

Dissolving Blood Clots Thromboembolisms can be treated with tissue plasminogen activator (tPA) 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 UNIT B TO PREVIOUS SLIDE Section 10.8 Chapter 10: Circulatory System and Lymphatic System

Heart Transplants and Artificial Hearts UNIT B TO PREVIOUS SLIDE Section 10.8 Chapter 10: Circulatory System and Lymphatic System 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 Figure 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.

Heart Transplants and Artificial Hearts UNIT B TO PREVIOUS SLIDE Section 10.8 Chapter 10: Circulatory System and Lymphatic System Artificial hearts A total artificial heart (e.g., AbioCor) 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 Figure A total artificial heart. The AbioCor replacement heart is designed to be implanted within the chest cavity.

Check Your Progress 1.Define the following: thrombus, embolus, and aneurysm. 2.Describe some possible complications with stents placed in blocked arteries (that is, what could go wrong). 3.Identify treatment options, as well as potential limitations, for patients who need their heart replaced. UNIT B TO PREVIOUS SLIDE Section 10.8 Chapter 10: Circulatory System and Lymphatic System

UNIT B TO PREVIOUS SLIDE Section 10.8 Chapter 10: Circulatory System and Lymphatic System