The Heart Heart pumps over 1 million gallons per year Over 60,000 miles of blood vessels I. Layers of Heart Wall A. Pericardium 1. protects and anchors the heart, prevents overstretching B. Myocardium 1. cardiac muscle layer is the bulk of the heart C. Endocardium 1. chamber lining & valves II. Structures of the Heart Brachiocephalic trunk aorta Superior vena cava Left subclavian artery Left common carrotid Right atrium inferior vena cava Right pulmonary vein tricuspid Papillary muscle Right ventricle Descending aorta Interventricular septum Left ventricle myocardium Mitral/bicuspid Aortic semi-lunar Left atrium left pulmonary artery pulmonary semi-lunar Chordae tendinae A. Two closed circuits, the systemic and pulmonic B. Pulmonary circulation 1. Right atrium pumps blood through the tricuspid valve to the right ventricle 2. Right ventricle pumps blood through the pulmonary semi- lunar valve to pulmonary trunk 3. pulmonary trunk branches into left and right pulmonary arteries 4. Pulmonary arteries carry blood to lungs for exchange of gases Which gases and in what direction? 5. Oxygenated blood returns to the heart through the pulmonary veins into the left ventricle A. Two closed circuits, the systemic and pulmonic B. Pulmonary circulation 1. Right atrium pumps blood through the tricuspid valve to the right ventricle 2. Right ventricle pumps blood through the pulmonary semi- lunar valve to pulmonary trunk 3. pulmonary trunk branches into left and right pulmonary arteries 4. Pulmonary arteries carry blood to lungs for exchange of gases Which gases and in what direction? 5. Oxygenated blood returns to the heart through the pulmonary veins into the left ventricle III. Blood Circulation C. Systemic circulation 1. Left atrium pumps blood though the mitral valve (bicuspid) to the left ventricle Why is this valve replaced the most often? 2. left ventricle pumps oxygenated blood through the aortic semi-lunar valve into aorta Why is the myocardium of this chamber the thickest? 3. Aorta branches into many arteries that travel to organs 4. Arteries branch into many arterioles in tissue. 5. Arterioles branch into thin-walled capillaries for exchange of gases and nutrients 6. Deoxygenated blood begins its return in venules 7. Venules merge into veins and return to right atrium via the vena cavas C. Systemic circulation 1. Left atrium pumps blood though the mitral valve (bicuspid) to the left ventricle Why is this valve replaced the most often? 2. left ventricle pumps oxygenated blood through the aortic semi-lunar valve into aorta Why is the myocardium of this chamber the thickest? 3. Aorta branches into many arteries that travel to organs 4. Arteries branch into many arterioles in tissue. 5. Arterioles branch into thin-walled capillaries for exchange of gases and nutrients 6. Deoxygenated blood begins its return in venules 7. Venules merge into veins and return to right atrium via the vena cavas Blood Circulation (cont) IV. Blood Flow Off Descending Aorta A. Common carotid artery (left) 1. First branch coming off of the aorta and it carries blood to head and brain 2. Returns through jugular veins to superior vena cava B. Left & right Subclavian arteries carries blood to the arms and the subclavian veins return blood to the superior vena cava. A. Common carotid artery (left) 1. First branch coming off of the aorta and it carries blood to head and brain 2. Returns through jugular veins to superior vena cava B. Left & right Subclavian arteries carries blood to the arms and the subclavian veins return blood to the superior vena cava. Blood flow off Descending Aorta (2) C. Celiac artery carries blood to stomach, spleen and liver D. Portal vein leads to the liver and leaves through the hepatic (liver) vein to inferior vena cava. E. Superior mesenteric artery carries blood to the small intestine, which in turn connects to the portal vein. a) This way all materials entering the blood stream from the digestive tract are sent directly to the liver for detoxification. C. Celiac artery carries blood to stomach, spleen and liver D. Portal vein leads to the liver and leaves through the hepatic (liver) vein to inferior vena cava. E. Superior mesenteric artery carries blood to the small intestine, which in turn connects to the portal vein. a) This way all materials entering the blood stream from the digestive tract are sent directly to the liver for detoxification. Blood flow off Descending Aorta (3) F. Inferior mesenteric artery leads to large intestine (and small, but mostly large) 1. Large intestine leads to internal iliac vein (hypogastric) that connects to the inferior vena cava G. The Iliac arteries branches to supply blood to reproductive and excretory organs, as well as the legs 1. Blood returns through iliac veins to inferior vena cava F. Inferior mesenteric artery leads to large intestine (and small, but mostly large) 1. Large intestine leads to internal iliac vein (hypogastric) that connects to the inferior vena cava G. The Iliac arteries branches to supply blood to reproductive and excretory organs, as well as the legs 1. Blood returns through iliac veins to inferior vena cava HEART QUESTIONS How many times will your heart beat in 80 years? How much blood is pumped with each heart beat? How many times will your heart beat in 80 years? How much blood is pumped with each heart beat? V. Cardiac Cycle A. Atrial diastole 1. both atria fill with blood 2. atrioventricular valves are open and the semilunar valves are closed 3. 75% of ventricular filling occurs now 4. lasts about 0.7 seconds B. Atrial systole 1. atria contract forcing the remaining 25% of the blood into the ventricles 2. lasts about 0.1 seconds A. Atrial diastole 1. both atria fill with blood 2. atrioventricular valves are open and the semilunar valves are closed 3. 75% of ventricular filling occurs now 4. lasts about 0.7 seconds B. Atrial systole 1. atria contract forcing the remaining 25% of the blood into the ventricles 2. lasts about 0.1 seconds Cardiac Cycle (2) C. Ventricular diastole 1. ventricles are relaxing 2. lasts about 0.5 seconds D. Ventricular systole 1. ventricles are contracting 2. blood is being forced into the aorta and pulmonary arteries. 3. the semilunar valves are open and the atrioventricular valves are closed. 4. lasts about 0.3 seconds C. Ventricular diastole 1. ventricles are relaxing 2. lasts about 0.5 seconds D. Ventricular systole 1. ventricles are contracting 2. blood is being forced into the aorta and pulmonary arteries. 3. the semilunar valves are open and the atrioventricular valves are closed. 4. lasts about 0.3 seconds VI. Cardiac Conduction System A. Impulse originates in sinoatrial node (SA node or pacemaker) which is located in the superior region of the right atrium. B. Impulse spreads across both atria which causes them to contract at the same time. C. The impulse reaches atrioventricular node (AV node) located at the top of the right ventricle. A. Impulse originates in sinoatrial node (SA node or pacemaker) which is located in the superior region of the right atrium. B. Impulse spreads across both atria which causes them to contract at the same time. C. The impulse reaches atrioventricular node (AV node) located at the top of the right ventricle. Cardiac Conduction System (cont) D. From the AV node the impulse passes through the atrioventricular bundle node to (Bundle of His). E. The Bundle of His branches off into right and left bundle branches.. F. The impulse now flows through the many branches of the Purkinje fibers which pass deep into the ventricular myocardium. D. From the AV node the impulse passes through the atrioventricular bundle node to (Bundle of His). E. The Bundle of His branches off into right and left bundle branches.. F. The impulse now flows through the many branches of the Purkinje fibers which pass deep into the ventricular myocardium. AV node Pacemaker Bundle of His Purkinje fibers VII. Electrocardiogram-ECG or EKG A. Action potentials of all active cells can be detected and recorded B. The machine amplifies electrical impulses generated by your muscles. C. 4 basic parts to analyze: 1. P wave 2. P to Q interval 3. QRS complex 4. T wave VIII. ECG Analysis A. Parameters 1. Horizontal Axis a) Measures time of duration. b) Each box or mm = 0.04 seconds A. Parameters 1. Horizontal Axis a) Measures time of duration. b) Each box or mm = 0.04 seconds 2.Vertical Axis a)Measures voltage or amplitude b)Each box or mm = 0.1 mV P-Wave 1. Depolarization of the atria (atrial systole) 2. Amplitude of P-Wave should be less than 0.2 mV to 0.3 mV 3. Duration of P-Wave should be less than 0.11 seconds 1. Depolarization of the atria (atrial systole) 2. Amplitude of P-Wave should be less than 0.2 mV to 0.3 mV 3. Duration of P-Wave should be less than 0.11 seconds QRS Complex 1. Atria repolarization (atrial diastole) 2. Ventricle depolarization (ventricular systole) 3. Amplitude should be greater than 0.5 mV in leads 1, 2, or 3 1. Measured from tip of R to bottom of S 4. Duration should be less than 0.12 secs. 1. Atria repolarization (atrial diastole) 2. Ventricle depolarization (ventricular systole) 3. Amplitude should be greater than 0.5 mV in leads 1, 2, or 3 1. Measured from tip of R to bottom of S 4. Duration should be less than 0.12 secs. T-Wave (isoelectric) 1. Repolarization of ventricles (ventricular diastole) 2. Amplitude should be less than 0.5 and greater than 1/10 of R wave for that segment. a) T-wave should be on the isoelectric line 3. Duration not a concern 4. T-wave should be in the same direction as the R- wave 1. Repolarization of ventricles (ventricular diastole) 2. Amplitude should be less than 0.5 and greater than 1/10 of R wave for that segment. a) T-wave should be on the isoelectric line 3. Duration not a concern 4. T-wave should be in the same direction as the R- wave P-Q Interval 1. Measured from beginning of P to beginning of Q. 2. Between 0.12 and 0.2 second duration. 3. Too long indicates AV block. 1. Measured from beginning of P to beginning of Q. 2. Between 0.12 and 0.2 second duration. 3. Too long indicates AV block. ST Segment 1. Amplitude should be isoelectric a) If depressed more than 2 mm indicates ischemic heart. b) Most often caused by atherosclerosis. 2. Duration should be between sec. 1. Amplitude should be isoelectric a) If depressed more than 2 mm indicates ischemic heart. b) Most often caused by atherosclerosis. 2. Duration should be between sec. Heart Rate 1. HR= 60/(R to R Interval in seconds) Cardiac Cycle Regulation of Heart Rate I. Cardiac Output (CO) A. The amount of blood the heart pumps in 1 minute. B. CO = stroke volume (SV) x heart rate (HR) 1. example: 70 mL of blood/beat x 70 beats/min. = 4900 mL/min. A. The amount of blood the heart pumps in 1 minute. B. CO = stroke volume (SV) x heart rate (HR) 1. example: 70 mL of blood/beat x 70 beats/min. = 4900 mL/min. II. Influences on Stroke Volume A. Preload (affect of stretching heart muscle) 1. Frank-Starling Law of Heart a) The longer the filling time, the greater the stretch of cardiac muscle b) more muscle is stretched, greater force of contraction c) This explains why athletes have lower resting heart rates but the same cardiac output d) more blood more force of contraction results B. Contractility 1. autonomic nerves, hormones, Ca +2 or K + levels C. Afterload 1. amount of pressure created by the blood in the way 2. high blood pressure creates high afterload A. Preload (affect of stretching heart muscle) 1. Frank-Starling Law of Heart a) The longer the filling time, the greater the stretch of cardiac muscle b) more muscle is stretched, greater force of contraction c) This explains why athletes have lower resting heart rates but the same cardiac output d) more blood more force of contraction results B. Contractility 1. autonomic nerves, hormones, Ca +2 or K + levels C. Afterload 1. amount of pressure created by the blood in the way 2. high blood pressure creates high afterload III. Control Centers for Heart Rate A. Two centers found in the medulla 1. Cardioacceleratory center a) has a sympathetic nerve (cardioaccelerator nerve) that connects to the SA node of the heart. 2. Cardioinhibitory center a) has a parasympathetic nerve (vagus nerve) that connects to the SA node of the heart. A. Two centers found in the medulla 1. Cardioacceleratory center a) has a sympathetic nerve (cardioaccelerator nerve) that connects to the SA node of the heart. 2. Cardioinhibitory center a) has a parasympathetic nerve (vagus nerve) that connects to the SA node of the heart. IV. Factors that effect heart rate A. Blood Pressure (BP) 1. Carotid Sinus Reflex: a) As the BP in the carotid sinus rises the walls of the carotid sinuses stretch (baroreceptors) b) Stretching increases stimulation of the glossopharyngeal nerve, which leads to the cardioinhibitory center in the medulla. c) The inhibitory center stimulates the Vagus nerve which slows down the heart rate d) Therefore a drop in HR, produced a drop in CO, which produced a drop in blood pressure, that reduced the amount of stretch in the carotid sinus. e) What happens if there is a drop in blood pressure in the carotid sinus? A. Blood Pressure (BP) 1. Carotid Sinus Reflex: a) As the BP in the carotid sinus rises the walls of the carotid sinuses stretch (baroreceptors) b) Stretching increases stimulation of the glossopharyngeal nerve, which leads to the cardioinhibitory center in the medulla. c) The inhibitory center stimulates the Vagus nerve which slows down the heart rate d) Therefore a drop in HR, produced a drop in CO, which produced a drop in blood pressure, that reduced the amount of stretch in the carotid sinus. e) What happens if there is a drop in blood pressure in the carotid sinus? Factors that effect heart rate (cont) 2. Aortic reflex (regulates BP to rest of body) a) Right Atrial (Bainbridge) reflex b) There are baroreceptors located in the right atrium and in the superior and inferior vena cavas. c) When these are stimulated heart rate increases. Why increase heart rate instead of decrease? 2. Aortic reflex (regulates BP to rest of body) a) Right Atrial (Bainbridge) reflex b) There are baroreceptors located in the right atrium and in the superior and inferior vena cavas. c) When these are stimulated heart rate increases. Why increase heart rate instead of decrease? Factors that effect heart rate (cont) B. Chemical Factors 1. CO 2 a) increases heart rate 2. Adrenaline (epinephrine) a) increases heart rate 3. Ca 2+ a) increases heart rate 4. Na + and K + a) lower heart rate B. Chemical Factors 1. CO 2 a) increases heart rate 2. Adrenaline (epinephrine) a) increases heart rate 3. Ca 2+ a) increases heart rate 4. Na + and K + a) lower heart rate Factors that effect heart rate (cont) C. Other factors 1. Sex a) females have higher heart rates 2. Age a) older-slower 3. Exercise a) increase b) person who exercises regularly has a lower resting heart rate than one who doesn't - called Bradycardia 4. Temperature a) Higher temperature, higher heart rate C. Other factors 1. Sex a) females have higher heart rates 2. Age a) older-slower 3. Exercise a) increase b) person who exercises regularly has a lower resting heart rate than one who doesn't - called Bradycardia 4. Temperature a) Higher temperature, higher heart rate Cardiovascular Disease (CVD) In the U.S.1 million deaths/year I. Coronary heart disease (56%) A. Cause 1. Slow build up of fatty plaque (atherosclerosis) along the walls of the coronary blood vessels which reduces blood flow to heart 2. The drop in O 2 levels (ischemia) causes a angina which could lead to myocardial infarction. A. Cause 1. Slow build up of fatty plaque (atherosclerosis) along the walls of the coronary blood vessels which reduces blood flow to heart 2. The drop in O 2 levels (ischemia) causes a angina which could lead to myocardial infarction. B. Diagnosis 1. Outward symptoms of a heart attack: a) pain in chest and left arm b) cyanosis of lips c) nausea d) dizziness e) shortness of breath f) cold sweat g) denial 1. Outward symptoms of a heart attack: a) pain in chest and left arm b) cyanosis of lips c) nausea d) dizziness e) shortness of breath f) cold sweat g) denial Diagnosis (cont) 2. Exercise ECG a) ST Depression b) Problems with PR interval 3. Angiogram a) A catheter is inserted into femoral artery of pelvis and worked into the aorta. b) Then dye is injected through catheter. c) A fluoroscope will show the dye pathway. d) Any narrowing or blockages will show up on the fluoroscope. 2. Exercise ECG a) ST Depression b) Problems with PR interval 3. Angiogram a) A catheter is inserted into femoral artery of pelvis and worked into the aorta. b) Then dye is injected through catheter. c) A fluoroscope will show the dye pathway. d) Any narrowing or blockages will show up on the fluoroscope. C. Treatment 1. Bypass surgery a) remove a vein from the leg and use it to bypass a blockage in heart vessel b) stop heart and put on a heart lung machine 2. Angioplasty (see angiogram) a) Catheter with specialized tip is positioned where the coronary artery is narrowed or blocked. b) Use syringe to blow up catheters balloon (fig , page 599). c) Balloon presses the plaque up against the walls of the vessel. 1. Bypass surgery a) remove a vein from the leg and use it to bypass a blockage in heart vessel b) stop heart and put on a heart lung machine 2. Angioplasty (see angiogram) a) Catheter with specialized tip is positioned where the coronary artery is narrowed or blocked. b) Use syringe to blow up catheters balloon (fig , page 599). c) Balloon presses the plaque up against the walls of the vessel. By-pass Graft Coronary Angioplasty CVD II. Stroke 20% A. The interruption of blood flow to the brain B. Causes 1. thrombus vs. embolus 2. atherosclerosis (has no symptoms) 3. aneurysm-broken blood vessel II. Stroke 20% A. The interruption of blood flow to the brain B. Causes 1. thrombus vs. embolus 2. atherosclerosis (has no symptoms) 3. aneurysm-broken blood vessel Stent in an Artery Maintains patency of blood vessel CVD III. Hypertension 7% A. Chronic high blood pressure B. More common in black males than white. IV. Myocardial degeneration 5% A. Heart muscle degenerates V. Arteriosclerosis 4% A. Hardening of the arteries VI. Rheumatic fever 2% A. Childhood disease that damages heart valves III. Hypertension 7% A. Chronic high blood pressure B. More common in black males than white. IV. Myocardial degeneration 5% A. Heart muscle degenerates V. Arteriosclerosis 4% A. Hardening of the arteries VI. Rheumatic fever 2% A. Childhood disease that damages heart valves VII.Risk Factors associated with Cardiovascular Disease A. age B. sex C. genetics D. diets high in fat (hyperlipidemia) E. high blood pressure F. smoking G. stress H. alcohol I. obesity J. inactivity A. age B. sex C. genetics D. diets high in fat (hyperlipidemia) E. high blood pressure F. smoking G. stress H. alcohol I. obesity J. inactivity VIII.First Heart Attack Risk Test A. Age: 1. Men: 0 pts = Less than 35, 1 pt = 35 to39, 2 pts = 40 to 48, 3 pts = 49 to 53, 4 pts = Women: 0 pts = Less than 42, 1 pt = 43 to 45, 2 pts = 46 to 54, 3 pts = 55 to 73, 4 pts = 74+. B. Family History: 2 pts if family has a history (parents and/or grandparents) of heart disease or heart attack before age 60. C. Inactivity: 1 pt if you rarely exercise or do anything physically demanding. D. Weight: 1 pt if you are more than 20 pounds overweight. A. Age: 1. Men: 0 pts = Less than 35, 1 pt = 35 to39, 2 pts = 40 to 48, 3 pts = 49 to 53, 4 pts = Women: 0 pts = Less than 42, 1 pt = 43 to 45, 2 pts = 46 to 54, 3 pts = 55 to 73, 4 pts = 74+. B. Family History: 2 pts if family has a history (parents and/or grandparents) of heart disease or heart attack before age 60. C. Inactivity: 1 pt if you rarely exercise or do anything physically demanding. D. Weight: 1 pt if you are more than 20 pounds overweight. First Heart Attack Risk Test (cont) E. Inactivity: 1 pt if you rarely exercise or do anything physically demanding. F. Weight: 1 pt if you are more than 20 pounds overweight. G. Smoker: 1 pts if you smoke H. Diabetes: 1 pt if you are male, 2 pts if your are female. I. Total Cholesterol Level: 0 pts if you are less than 240 mg/dl, 1 pt if you are mg/dl and 2pts if you are greater than 315 mg/dl. E. Inactivity: 1 pt if you rarely exercise or do anything physically demanding. F. Weight: 1 pt if you are more than 20 pounds overweight. G. Smoker: 1 pts if you smoke H. Diabetes: 1 pt if you are male, 2 pts if your are female. I. Total Cholesterol Level: 0 pts if you are less than 240 mg/dl, 1 pt if you are mg/dl and 2pts if you are greater than 315 mg/dl. First Heart Attack Risk Test (cont) J. HDL Level: 2 pts if you are under 30 mg/dl, 1 pt if you are mg/dl or 1 pt if you are over 60 mg/dl, and 0 pts if you are mg/dl. K. Blood Pressure (Systolic): 0 pts if less than 140 mmhg, 1 pt if mm/hg and 2 pts if greater than 170 mmhg. L. Scoring the test: Any value above four represents an above average risk; the higher the number, the greater the risk. J. HDL Level: 2 pts if you are under 30 mg/dl, 1 pt if you are mg/dl or 1 pt if you are over 60 mg/dl, and 0 pts if you are mg/dl. K. Blood Pressure (Systolic): 0 pts if less than 140 mmhg, 1 pt if mm/hg and 2 pts if greater than 170 mmhg. L. Scoring the test: Any value above four represents an above average risk; the higher the number, the greater the risk. IX.Benefits of Aerobic Exercise A. Normalizes BP B. Bradycardia 1. heart pumps more blood per beat 2. more efficient C. Increases the number of RBC's D. Increases caloric output E. Decreases LDL's and increases HDL's 1. High density lipoproteins (HDL's) contain more protein than fat and HDL's are able to remove low density lipoproteins (LDL's) from the blood stream 2. LDL's have a higher proportion of fat and tend to accumulate along the walls of the arteries of the body, and heart in cerebral arteries A. Normalizes BP B. Bradycardia 1. heart pumps more blood per beat 2. more efficient C. Increases the number of RBC's D. Increases caloric output E. Decreases LDL's and increases HDL's 1. High density lipoproteins (HDL's) contain more protein than fat and HDL's are able to remove low density lipoproteins (LDL's) from the blood stream 2. LDL's have a higher proportion of fat and tend to accumulate along the walls of the arteries of the body, and heart in cerebral arteries X. Designing A Good Exercise Program A. Correct intensity as measured by heart rate 1. Heart must work athlete 80-90% of the max. HR normal 70-80% of the max. HR older60-70% of the max. HR 2. Maximum HR= 220 age e.g. a normal person 40 years of age (220-40) x 70% 180 x 0.7 =126.0 beats/min. 180 x 0.8=144 beats/min. A. Correct intensity as measured by heart rate 1. Heart must work athlete 80-90% of the max. HR normal 70-80% of the max. HR older60-70% of the max. HR 2. Maximum HR= 220 age e.g. a normal person 40 years of age (220-40) x 70% 180 x 0.7 =126.0 beats/min. 180 x 0.8=144 beats/min. Designing A Good Exercise Program (cont) B. Correct duration minutes or longer at target heart rate C. Frequency times a week or every other day B. Correct duration minutes or longer at target heart rate C. Frequency times a week or every other day