7 Further development of heart Tubular heart elongates and develops dilations and constrictions :AtriumSinus venosusVentricleBulbus cordisTruncus arteriosus
8 Partitioning of Primordial Heart Partitioning of Atrioventricular CanalCardiac jelly → endocardial cushion (by the end of 4th week)Atrioventricular canal → left and right atrioventricular canalEndocardial cell → AV valves (mitral valve & tricuspid valve)
9 Partitioning of Primordial Atrium Foramen primum - becomes smaller & disappearsForamen secundum – becomes larger (fusion of perforations in the central part of septum primum)Septum secundum overlaps foramen secundum → oval foramen formedSeptum primum- cranial part disappears- caudal part → valve of oval foramen → oval fossa (after birth)
10 Changes in Sinus Venosus Initiallyright and left sinus are the same size.4th week- Right horn enlarge (1)anastomosis (2) right vitelline vein change into IVC sinus vanarum (smooth part of RA)- Left horn – size decreases coronary sinus- Caudal part of sinuatrial valve valve of IVC and coronary sinus
11 Partitioning of Primordial Ventricle Muscular part of the IV septum enlarging ventricle myoblast- ( 6th) IV foramen still exists- ( 7th) IV foramen closed — right & left bulbar ridges endocardial cushionMembranous part of the IV septum right side of the endocardial cushionComplete partitioning- aorticopulmonary septum + membranous part of IV septum + muscular part of IV septum
12 Partitioning of Bulbus Cordis and Truncus Arteriosus Fusion of bulbar ridges and truncal ridgesaorticopulmonary septum180 degree spiraling of aorticopulmonary septumdivides aorta & pulmonary trunkFormation of semilunar valves- by 3 swellings of subendocardial tissue- aortic valve post., right & left cusps- pulmonary valve ant., right & left cusps
13 Congenital cardiovascular defects What is congenital cardiovascular defects?What causes congenital heart defects?What are the symptoms of congenital defects?How are congenital defects diagnosed?How are congenital heart defects treated?
14 Types of congenital defects Obstruction defectsSeptal DefectCyanotic defects
15 Obstruction defectsObstructions are called stenoses and can occur in heart valves, arteries or veins
17 Cyanotic defects Another classification of heart defects is congenital cyanotic heart defects. In these defects, blood pumped to the body contains less-than-normal amounts of oxygen. This results in a condition called cyanosis , a blue discoloration of the skin. The term "blue babies" is often applied to infants with cyanosis.Examples of cyanotic defects are:Patent ductus arteriosusTetralogy of Fallot,Transposition of the great arteries,Tricuspid atresia,Pulmonary atresia,Truncus arteriosusTotal anomalous pulmonary venous connection.