MEDICAL SURGICAL

MEDICAL-SURGICAL Layer of the Heart: - Endocardium ( inner ) - facilitates blood flow, contains valve & chambers - Myocardium ( middle ) - contracting muscle, cardiac muscle - Pericardium ( outer ) o Layer of Pericardium  Visceral ( epicardium )  Pericardial ( 5-20cc of fluid ) serves as cushion, lubricant  Parietal Circulation: from to right Vena cava Lungs deoxygenated Pulmonary circulation left Pulmonary veins System oxygenated Systemic circulation Valves & Chambers: - AV valves ( atrioventricular valves ) “Atria” o 1 way flow of blood  Tricuspids( right atria )  Bicuspids/ Mitral ( left atria ) - SL valves ( semilunar valves )  Pulmonary SL valve  Aortic SL valve Ventricle contract : Semi Lunar valve open - ( AV valve closed ) Ventricle relax : Semi Lunar valve closed ( blood filling ) - ( Av valve open ) Coronary Artery - Branch out from ascending aorta Right Coronary Artery – supplying the Right Atrium / Right Ventricle / inferior portion of Left Ventricle Left Coronary Artery o Circumflex – supplying the Left Atrium / posterior portion of Left Ventricle o Left Anterior Descending Artery (LADA) – supplying the Left Ventricle /Apex Electrophysiologic Properties A – utomacity – C – ontractility – transmit impulse C – onductivity – contraction E – xcitability – respond to stimuli R – efractiones – ability to finish a response before initiating another response. Conduction System - SA node ( sinoatrial node ) main pacemaker of the heart : 60 – 100bpm - AV node ( atrioventricular node ) 2 nd pacemaker of the heart : 40 – 60bpm - Bachmann’s node ( node in the left atrium ) SA node Intranodal tract AV node Bundle of HIS Bundle branches Right Purkinje Left Purkinje Cardiac Cycle - Two main phase o Systole : contraction / ejection o Diastole : relaxation / refill  Difference between Systolic & Diastolic is the PULSE PRESSURE ( PP: 30 – 40cpm ) narrowed pulse – hypovolemia ( PP: 60cpm ) wided pulse – increased in Stroke volume Cardiac Output - Amount of blood pump by the heart particularly by the left ventricle per minute Stroke Volume (SV) – amount of blood pump by the heart in every beat SV = amt (ml) Beat - Contractility : ( Inotropic ) ability of cardiac muscle to contract - Preload : amount of the blood from the ventricle after the end of diastolic phase (Frank Staring Law : the greater the stretch, the better the pump) o Venous returns o Regurgitation of the blood - Afterload : resistance of LV must surpass as the heart pump blood to the circulation o Systemic resistance ( HPN ) o Blood viscosity ( DM. polycythemia vera, multiple myeloma ) Heart Rate ( HR ) – number of heart beat