CVS2 - Coronary & Foetal Circulation PDF

Anatomy of the Heart 3 Coronary Circulation, Conducting System & Foetal Circulation Niggy Gouldsborough  Coronary Circulation anterior view...

Anatomy of the Heart 3 Coronary Circulation, Conducting System & Foetal Circulation Niggy Gouldsborough  Coronary Circulation anterior view LCA The heart receives 250 ml/min blood circumflex Blood delivered to myocardium during ventricular RCA relaxation left coronary artery (LCA) marginal - anterior interventricular anterior interventricular - circumflex posterior view RCA right coronary artery (RCA) - marginal artery - posterior interventricular posterior interventricular (Ashton, 2015)  Coronary Circulation The great, middle and small cardiac veins drain into the coronary sinus which empties into the right atrium. The anterior cardiac veins drain directly into the right atrium anterior view of heart posterior view of heart coronary sinus great cardiac vein anterior cardiac veins middle cardiac vein small cardiac vein (Ashton, 2015)  Angiography The patency of the coronary vessels can be examined by angiography 100 50 East West 0 1st 3rd North Qtr Qtr NORMAL RESTRICTED  Cardiac Conducting System Effective heart contraction is coordinated by the cardiac conducting system SA node Consists of non-contractile cells that initiate electrical impulses - Sinoatrial (SA) node AV node AV bundle - Atrioventricular (AV) node bundle - AV bundle (bundle of His) branches - Right & left bundle branches - Purkinje fibres (Ashton, 2015) purkinje fibres  Electrocardiogram (ECG) The electrical activity of the heart can be measured using an ECG  Foetal Circulation Different from usual circulation because oxygen and nutrients are received from the placenta via the umbilical vein Need to bypass non functional lungs (Ashton, 2015)  Foetal Circulation ductus arteriosus foramen Three circulatory shortcuts ovale 1. Foramen ovale connects the right to the left atria - bypassing right ventricle and ductus venosus pulmonary system 2. Ductus arteriosus connects the umbilical vein pulmonary trunk to arch of aorta – bypassing pulmonary system and left side of heart umbilical arteries 3. Ductus venosus connects the umbilical placenta vein to inferior vena cava - bypasses the liver (Saladin, 2015)  Foetal circulation Ductus arteriosus Pulmonary trunk Aorta Foramen ovale LA RA RV LV Foetal circulation Aorta LA RA RV LV  Changes at birth Newborn takes 1st breath Lungs expand Umbilical LA pressure cord tied Blood rushes into pulmonary Foramen ovale Umbilical circulation closes to vessels close become fossa ovalis O2 levels rise Ductus venosus fibroses Constricts ductus arteriosus Summary of changes Foetus Adult Ductus Ligamentum venosus venosum Foramen ovale Fossa ovalis Ductus Ligamentum arteriosus arteriosum