1 THE HEART & HEART DISEASE Chapter 13

2 The Heart Triangular organ located in mediastinum Two thirds, left of the midline One third, right of the midline Apex on the diaphragm Size of closed fist In thoracic cavity, between sternum in front and vertebrae behind it

3 Heart Anatomy Four chambers or hollow cavities Atria, 2 upper chambers Receiving chambers Thinner,less muscular walls Ventricles, 2 lower chambers Discharging chambers Thicker,cardiac muscle

4 Heart Anatomy Myocardium, muscle of the heart Endocardium,thin layer of smooth tissue lining each chamber of the heart Pericardium,membrane covering the heart,consist of 2 layers Visceral, inner layer Parietal, outer layer

5 Heart Action Muscular pumping device distributing blood to all parts of the body constantly Systole: contraction of the heart muscle Diastole:relaxation of the heart muscle Efficient pumping depends on controlling the direction of blood flow

6 Heart Valves Atrioventricular valves,separate the atrial chambers above from ventricles below Mitral/bicuspid valve between left atrium & ventricle Tricuspid valve between right atrium & ventricle

7 Heart Valves Semilunar valves,between ventricles and large arteries that carry blood away from the heart Pulmonary,allows blood out of right ventricle,into the lung Aortic,allows blood out of the left ventricle into the aorta

8 Heart Sounds Two heart sounds, rhythmical & repetitive Lub-Dup, contraction-relaxation Lub,first sound,abrupt closure of AV valves Dup,second sound,closing of semilunar valves (ventricles relax) Heart murmur,abnormal heart sounds due to incompetent valves,swishing sound at either beginning or end of “lub-dup”

9 Kinds of Blood Vessels Arteries..carry blood from ventricles to all parts of the body Arteries carry oxygenated blood Pulmonary artery carries unoxygenated blood Arterioles connect arteries with capillaries

10 Kinds of Blood Vessels Capillaries have thin walls that allow nutrients, oxygen and carbon dioxide to move in and out of the blood easily Venules, small veins that connect veins with capillaries Veins carry blood from all parts of the body and return it to the heart

11 Blood Flow thru the Body Starts Right Atrium Thru Tricuspid valve Right Ventricle Thru Pulmonary valve Pulmonary artery Lungs ( O2 & CO2) Pulmonary veins

12 Blood Flow thru the Body Left Atrium Mitral valve Left Ventricle Aortic valve Aorta Body Arteries

Blood Flow thru the Heart: 13

14 Blood Flow thru the body Arterioles Capillaries(O2 & CO2 exchange) Venules Veins Superior or inferior vena cava Right atrium

15 Cardiac Cycle A complete heartbeat: 1 contraction & 1 relaxation Each cycle takes 0.8 seconds Average heart rate is 72 beats per minute Normal Range beats per minute Contraction Systole

16 Coronary Circulation Heart muscle requires a constant supply of nutrients & O2 to function properly Right Coronary Artery Left Coronary Artery first branches off the Aorta supplies heart muscle

17 Coronary Heart Disease Myocardial Infarction (heart Attack) death of cardiac muscle cells resulting from inadequate blood supply Coronary thrombosis, blood clot occluding the coronary artery of the heart Atherosclerosis,hardening of the arteries in which lipids build up on the inside of the blood vessels

Heart Attack/Coronary Thrombosis 18

19 Heart Disorders Endocarditis, inflammation of the lining of the heart Thrombosis, formation of a clot inside a blood vessel Pericarditis,inflammation of the pericardium

20 Heart Disorders Pericardial effusion: accumulation of fluid, pus, or blood between the pericardial layers Cardiac tamponade: compression of the heart caused by fluid buildup in the pericardial space

21 Valve Disorders Incompetent valves leak,allowing some blood to flow back into the chamber Stenosed valves are narrower than normal, slowing blood flow from chamber Mitral valve prolapse (MVP)where flaps extend back into the left atrium causing leaking Rheumatic heart disease caused by improperly treated strep infection,results inflammation and valve stenosis or deformity

22 Conduction System of the Heart Electrical impulses (signals) are necessary to coordinate the effective pumping of the cardiac muscles Sinoatrial node, the pacemaker AV node Bundle of HIS (AV bundle) Purkinje fibers Electrical impulses transformed into visible tracings by EKG or ECG Machines

23 Conduction System of the Heart: SA node (Sinoatrial) the pacemaker located in the wall of the right atrium near the opening of the superior vena cava

24 Conduction System of the Heart AV node(atrioventricular) located in the right atrium along the lower part of the interatrial septum

25 Conduction System of the Heart AV bundle(bundle of HIS) located in the septum of the ventricle

26 Conduction System of the Heart Purkinje fibers located in the walls of the ventricles

27 Electrocardiogram: P-wave: Depolarization of atria QRS:depolarization of ventricles T-wave: repolarization of ventricles

NORMAL HEART Stroke Volume..volume of blood ejected from one ventricle with each beat Cardiac output..amount of blood that one ventricle can pump each minute Average about 5 Liters per minute at rest 28

29 Cardiac Dysrhythmia Dysrhythmia:Abnormality of heart rhythm Heart Block, blockage of impulse conduction from atria to ventricles (treated with artificial pacemaker) Bradycardia..abnormally slow heart rate under 60 beats per min. Tachycardia..rapid heart rate, over 100 beats per min.

30 Cardiac Dysrhythmia Fibrillation..heart muscle fibers contract out of time with other muscle fibers producing no effective movement. Atrial fib treated by digitalis/defibrillation Ventricular fibrillation is life threatening, requires immediate defibrillation(Use of AED)

31 Heart Failure Cardiomyopathy..disease of the heart muscle that reduces pumping effectiveness Congestive Heart Failure (CHF) inability of the ventricles to pump effectively causing body to retain fluid/pulmonary edema Heart Failure..inability to pump enough blood to sustain life.

32 Cardiac Medication Digitalis…slows & increases the strength of cardiac contractions. (digoxin) Nitroglycerin..drug dilates coronary blood vessels and relieves angina. TPA…activates blood substance plasminogen which dissolves clots (streptokinase has similar effect)

33 Cardiac Medications Anticoagulants…prevent clot formation in pts. who have experienced M.I. (aspirin,coumadin, dicumarol) Beta-adrengic blockers..reduce the rate & strength of heart beat (propranolol) Calcium-channel blockers..block flow of calcium into cardiac muscle cells, reducing heart contraction (diltiazem, nicardipine, nifedipine)

FINALLY,THE END 34