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The Cardiovascular System. The Cardiovascular System. A closed system of the heart and blood vessels The heart pumps blood Blood vessels allow blood to circulate to all parts of the body
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The Cardiovascular System • A closed system of the heart and blood vessels • The heart pumps blood • Blood vessels allow blood to circulate to all parts of the body • The function of the cardiovascular system is to deliver oxygen and nutrients and to remove carbon dioxide and other waste products
The Heart • Location • Thorax between the lungs in the inferior mediastinum • Orientation • Pointed apex directed toward left hip • Base points toward right shoulder • About the size of your fist
The Heart Figure 11.1a–b
The Heart Figure 11.1c
The Heart Figure 11.2a
The Heart: Heart Wall Figure 11.2b
The Heart: Heart Wall • Three layers • Epicardium • Outside layer • This layer is the visceral pericardium • Connective tissue layer • Myocardium • Middle layer • Mostly cardiac muscle • Endocardium • Inner layer • Endothelium
The Heart: Heart Wall Figure 11.2c
The Heart: Chambers • Right and left side act as separate pumps • Four chambers • Atria • Receiving chambers • Right atrium • Left atrium • Ventricles • Discharging chambers • Right ventricle • Left ventricle
The Heart: Septa • Interventricular septum • Separates the two ventricles • Interatrial septum • Separates the two atria
The Heart: Valves • Allow blood to flow in only one direction to prevent backflow • Four valves • Atrioventricular (AV) valves—between atria and ventricles • Bicuspid (mitral) valve (left side of heart) • Tricuspid valve (right side of heart) • Semilunar valves—between ventricle and artery • Pulmonary semilunar valve • Aortic semilunar valve
Systemic and Pulmonary Circulations • Systemic circulation • Blood flows from the left side of the heart through the body tissues and back to the right side of the heart • Pulmonary circulation • Blood flows from the right side of the heart to the lungs and back to the left side of the heart
Systemic and Pulmonary Circulations Figure 11.3
The Heart: Associated Great Vessels • Arteries • Aorta • Leaves left ventricle • Pulmonary arteries • Leave right ventricle
The Heart: Associated Great Vessels • Veins • Superior and inferior venae cavae • Enter right atrium • Pulmonary veins (four) • Enter left atrium
Blood Flow Through the Heart • Oxygen is picked up and carbon dioxide is dropped off by blood in the lungs • Oxygen-rich blood returns to the heart through the four pulmonary veins • Blood enters the left atrium and travels through the bicuspid valve into the left ventricle • From the left ventricle, blood leaves the heart via the aortic semilunar valve and aorta
Coronary Circulation • Blood in the heart chambers does not nourish the myocardium • The heart has its own nourishing circulatory system consisting of • Coronary arteries—branch from the aorta to supply the heart muscle with oxygenated blood • Cardiac veins—drain the myocardium of blood • Coronary sinus—a large vein on the posterior of the heart, receives blood from cardiac veins • Blood empties into the right atrium via the coronary sinus
Heart Disease Are you at risk?
I. Heart Disease • Cardiovascular (Heart)Disease StatisticsEstimates for the year 2004 are that 79,400,000 Americans have one or more forms of cardiovascular disease (CVD). • High blood pressure — 72,000,000. • Coronary heart disease — 15,800,000. • Myocardial infarction (acute heart attack) — 7,900,000. • Angina (chest pain or discomfort caused by reduced blood supply to the heart muscle) — 8,900,000. • Stroke — 5,700,000.
I. Heart Disease • B. ________________- circulation of blood into heart muscle, to keep it alive. • Partial blockage in the coronary arteries may result in _____________ • Complete blockage in the coronary arteries may result in ______________ Coronary Angina Heart Attacks
II. Heart Attacks A. Definition- when the supply of blood and oxygen to an area of heart muscle is blocked, usually by a clot in a coronary artery, causing tissue damage and cellular death.
II. Heart Attacks Heart Attacks are also known as: myocardial infarction, or M.I.
II. Heart Attacks • B. Statistics: • Mortality — 452,327 deaths in the United States in 2004 (one of every 5 deaths). • Incidence — 1,200,000 new and recurrent coronary attacks per year. • About 38 percent of people who experience a coronary attack in a given year die from it.
II. Heart Attacks • C. Risk Factors: (just a few) • Increasing age • Male gender • Heredity (including race) • Tobacco smoke • High blood cholesterol levels • High blood pressure • Physical inactivity • Obesity and overweight
II. Heart Attacks • D. Signs and Symptoms of a • Heart Attack • Chest discomfort • Discomfort in one or both arms, the back, neck, jaw or stomach • Shortness of breath • cold sweat • nausea or lightheadedness
II. Heart Attacks • E. Care and Treatment: • At Home • Call 911 ASAP! • Lie the person down on a firm surface and elevate the legs slightly. • Loosen tight collars and belts. • Cover with a light blanket.. • Try to keep the airway open, CPR may be needed
II. Heart Attacks • E. Care and Treatment: • At Hospital • “Clot busting” medicine called thrombolytics may be given. 2. Coronary Catheterization where interventional cardiologists can open the blocked vessel. 3. Occasionally emergency bypass surgery may be required. • 4. Beta Blockers are a type of medicine that decreases blood pressure and slows the heart rate. These help decrease the workload of the heart. These are an important treatment in protecting the heart muscle.
Blood Vessels: The Vascular System • Transport blood to the tissues and back • Carry blood away from the heart • Arteries • Arterioles • Exchanges between tissues and blood • Capillary beds • Return blood toward the heart • Venules • Veins
Blood Vessels: The Vascular System Figure 11.9a
Blood Vessels: Microscopic Anatomy • Three layers (tunics) • Tunic intima • Endothelium • Tunic media • Smooth muscle • Controlled by sympathetic nervous system • Tunic externa • Mostly fibrous connective tissue
Blood Vessels: The Vascular System Figure 11.9b
Differences Between Blood Vessels • Walls of arteries are the thickest • Lumens of veins are larger • Larger veins have valves to prevent backflow • Skeletal muscle “milks” blood in veins toward the heart • Walls of capillaries are only one cell layer thick to allow for exchanges between blood and tissuea
Blood Vessels: The Vascular System Figure 11.10
Movement of Blood Through Vessels • Most arterial blood is pumped by the heart • Veins use the milking action of muscles to help move blood
Capillary Beds • Capillary beds consist of two types of vessels • Vascular shunt—vessel directly connecting an arteriole to a venule • True capillaries—exchange vessels • Oxygen and nutrients cross to cells • Carbon dioxide and metabolic waste products cross into blood
Capillary Beds Figure 11.11a
Capillary Beds Figure 11.11b
Major Arteries of System Circulation • Aorta • Largest artery in the body • Leaves from the left ventricle of the heart • Regions • Ascending aorta—leaves the left ventricle • Aortic arch—arches to the left • Thoracic aorta—travels downward through the thorax • Abdominal aorta—passes through the diaphragm into the abdominopelvic cavity
Major Arteries of System Circulation • Arterial branches of the ascending aorta • Right and left coronary arteries serve the heart
Major Arteries of Systemic Circulation • Arterial branches of the aortia arch (BCS) • Brachiocephalic trunk splits into the • Right common carotid artery • Right subclavian artery • Left common carotid artery splits into the • Left internal and external carotid arteries • Left subclavian artery branches into the • Vertebral artery • In the axilla, the subclavian artery becomes the axillary artery brachial artery radial and ulnar arteries
Pulse • Pulse • Pressure wave of blood • Monitored at “pressure points” in arteries where pulse is easily palpated • Pulse averages 70–76 beats per minute at rest
Pulse Figure 11.18
Blood Pressure • Measurements by health professionals are made on the pressure in large arteries • Systolic—pressure at the peak of ventricular contraction • Diastolic—pressure when ventricles relax • Write systolic pressure first and diastolic last (120/80 mm Hg) • Pressure in blood vessels decreases as distance from the heart increases
Comparison of Blood Pressures in Different Vessels Figure 11.19
Measuring Arterial Blood Pressure Figure 11.20a
Measuring Arterial Blood Pressure Figure 11.20b