ADVANCED BIOLOGY Heart SIZE, SHAPE, LOCATION Fist Hollow, cone shaped Mediastinum, Rests on diaphragm, posterior to sternum, Lungs on each side SIZE, SHAPE, LOCATION 2/3 lie to left of midsternal line Points toward right shoulder and left hip (apex, PMI) STRUCTURE/FUNCTION 4 CHAMBERS 2 Superior Atria 2 Inferior Ventricles Divided by interatrial/interventricular septum STRUCTURE/FUNCTION 4 CHAMBERS Most Mass in Right and Left Ventricles; pumping chambers Right= Forms most of the anterior surface Left= Forms inferoposterior aspect. Much more muscular! STRUCTURE/FUNCTION 4 CHAMBERS Posterior Atrial walls are smooth Anterior Atrial walls are rigid with bundles of muscle tissue Atria are the Receiving chambers; thin walled PATHWAY OF BLOOD Blood Flow through chambers Right Atrium Superior Vena Cava, Inferior Vena Cava, Coronary Sinus Left Atrium 4 Pulmonary veins pump blood back PATHWAY OF BLOOD Right Ventricle pumps blood to pulmonary trunk (goes to lungs) Left Ventricle pumps blood to Aorta, then out to body PATHWAY OF BLOOD Valves Atrioventricular (AV) Right Tricuspid Left Bicuspid Semilunar valves in pulmonary trunk/aorta PATHWAY OF BLOOD Pulmonary Circuit Pulmonary veins have blood with oxygen Pulmonary arteries have blood without oxygen PATHWAY OF BLOOD Systemic Circuit Arteries have blood with oxygen Veins have blood without oxygen See page 662 https://www.youtube.com/watch?v=oHMmtqKgs50 MAJOR BRANCHES Coronary Circulation supply blood to the heart Left Coronary runs to left side and divides into two parts MAJOR BRANCHES Anterior Interventricular artery Supplies blood to interventricular septum and anterior walls of ventricles MAJOR BRANCHES Circumflex artery Supplies blood to the left atrium and posterior wall of left ventricle MAJOR BRANCHES Right Coronary Runs to the right and also divides into two parts MAJOR BRANCHES Marginal Artery lateral part of right side of heart (atrium) Posterior interventricular artery Runs to the apex, supplies posterior ventricle walls MAJOR BRANCHES Cardiac Veins 1 major, 3 minor that dump into Coronary Sinus empties blood into the right atrium. Located on Posterior side MAJOR BRANCHES Great Cardiac Vein Found in the anterior interventricular sulcus (groove) Middle Cardiac Vein In posterior interventricular sulcus MAJOR BRANCHES Small Cardiac Vein runs along hearts right inferior margin Several other anterior cardiac veins empty directly into Right Atrium PROBLEMS? Myocardial Infarction (MI) Heart Attack. Blockage to coronary arteries reduces blood flow Damage to the Left Ventricle is the most serious CONDUCTION SYSTEM Intrinsic Cardiac Conduction System Non- contractile cells that initiate and distribute impulses CONDUCTION SYSTEM Sinoatrial Node (SA) In right atria Hearts Natural Pacemaker Atrioventricular Node (AV) In interatrial septum above tricuspid valve CONDUCTION SYSTEM Sinoatrial Node (SA) In right atria Hearts Natural Pacemaker Atrioventricular Node (AV) In interatrial septum above tricuspid valve CONDUCTION SYSTEM Atrioventricular Bundle (bundle of His) electrical connection between atria and ventricle Bundle Branches Run down interventricular septum to apex CONDUCTION SYSTEM Purkinje Fibers penetrate apex, run superiorly up ventricle walls Like milking a cow ECG Electrocardiograph Waves include P SA node sends first impulse ECG QRS Ventricular depolarization Precedes ventricular contraction T Ventricular Repolarization ECG Intervals P-R (P-Q) Beginning of atrial excitation and ventricular contraction Q-T Action potential through Heart CARDIAC CYCLE Systole Contraction of ventricles or atria Diastole Relaxation of ventricles or atria CARDIAC CYCLE Systolic Pressure Ventricular contraction 120mmHg Diastolic Pressure Ventricular refilling 80mmHg Hypertension High BP Hypotension Low BP HEART SOUNDS Lub-dub Lub AV valves close (systole) Dub SL valves close (diastole) HEART SOUNDS Murmurs obstructions in BV Thin walled vibrations CARDIAC OUTPUT CO = amount of blood pumped by each ventricle in 1 minute CO = HR x SV (stroke volume) SV = Volume of blood pumped out by ventricle (Force of contraction) CARDIAC OUTPUT CO = 75 bpm x 70mLpb CO = 5250 mL/min DEVELOPMENTAL ASPECTS Heart pumps by 23rd day 1-2 days later, chambers start to form Chambers are: DEVELOPMENTAL ASPECTS Sinus venosus receives all venous blood, becomes Rt. Atrium & Coronary Sinus, SA node Atrium becomes muscle ridged parts of atrium DEVELOPMENTAL ASPECTS Ventricle Becomes left ventricle Bulbus cordis Gives rise to the pulmonary trunk, first part of the aorta, most of the right ventricle AGE RELATED CHANGES Sclerosis Thickening of valve flaps Decline in Cardiac Reserve Heart is less able to adjust to changes AGE RELATED CHANGES Fibrosis of cardiac muscle Scarred nodes, increase in arrhythmias Atherosclerosis acclerated by inactivity, smoking, stress. CV disease