Development of the Cardiovascular System PDF

Development of the Cardiovascular system BY: Mohammed Ibrahim Ahmed MSc of Clinical Anatomy  The development of the cardiovasular system occurs at the middle of the third week of development. The heart is the first organ begins its function and the myocardium(cardiac muscle) comes f...

Development of the Cardiovascular system BY: Mohammed Ibrahim Ahmed MSc of Clinical Anatomy  The development of the cardiovasular system occurs at the middle of the third week of development. The heart is the first organ begins its function and the myocardium(cardiac muscle) comes from the splanchinc layer of the lateral mesoderm. Formation of the heart tube  The cardiogenic cells firstly appears in the cephalic region of the embryo anterior to the oropharyngeal membrane and neural tube.  With the development of the brain the heart descends into the cervical region and finally descends into the thorax.  When the embryo folds cephalocaudally it also folds laterally ,, thus the heart becomes continous expanded tube called the heart tube. Formation of the cardiac loop  The heart tube becomes more elongated and bends on day 23.  The cephalic portion (ventricular portion) moves downward, forward and to the right.  The caudal portion (atrial portion) moves dorsocranially and to the left.  This bending ends on day 28. Bulbus Cordis:  The proximal part of the bulbus cordis gives the trabeculated part of the right ventricle.  The middle part of the bulbus cordis called conus cordis gives the outflow of the both ventricle.  The distal part of the bulbus cordis called truncus arteriosus gives the proximal parts of the aorta and pulmonary trunk.  Ectopia Cordis Is a rare condition in which the heart is exposed to the surface of the thorax. This is due to sternal cleft.  Ectopia Cordis : the ventral body wall fail to fuse in the midline (sternal cleft) and the heart located on the surface of the thorax.  Dextrocardia: the heart located on the right side of the thorax instead of the left,,, may or may not associated with situs inversus(transposition of the viscera). Formation of the cardiac septa Atrial septa Ventricular septa Formation of conotruncal septum or Aorticopulmonary septum  Right superior truncus swelling: grows distally and to the left. Left inferior truncus swelling: grows distally and to the right.  This septum called spiral septum or aorticopulmonary septum ,,, defect in this septum lead to transposition of the great vessels. Cardiac septal defect  Patent foramen ovale (interatrial septal defect).  Patent ventricular foramen( interventricular septal defect).  Premature closure of foramen ovale. Patent foramen ovale Patent ductus arteriosus Tetralogy of fallot  The tetralogy of fallot includes the following: 1. Pulmonary valve stenosis. 2. Hypertrophy of the right ventricle. 3. Rupture of the membraneous part of the interventricular septum. 4. The aorta shifts its position and overlaps above the septum. Transposition of the great vessels  Transposition of the great vessels results from defect in the spiral septum and leads to aorta arises from the right ventricle and pulmonary trunk arises from the left venricle. Development of the vascular system Development of the arteries Development of the veins  The sinus venosus receive veinous blood from the right and left sinus horns. Each horn receive blood from three important veins: 1. Vitelline or omphalomesenteric vein. 2. Umbilical vein. 3. Common cardinal vein.  Parts of the inferior vena cava during development: 1. Hepatic segment of the inferior vena cava. 2. Renal segment of the inferior vena cava. 3. Sacrocardinal segment of the inferior vena cava. Fetal circulation Thanks