Heart Development, PDF

LO3 Septum Formation in Outflow Tract ©AK2023 Langman's Medical Emb ryology 14th ed. Fig. 13.27 21  LO4 transpositi...

LO3 Septum Formation in Outflow Tract ©AK2023 Langman's Medical Emb ryology 14th ed. Fig. 13.27 21  LO4 transposition of the great vessels (4.8/10,000 births) cyanotic conotruncal septum fails to take spiral course and goes straight down aorta originates from R ventricle and pulmonary a. from L ventricle associated with defect in membranous IV septum and patent ductus arteriosus ©AK2023 Langman's Medical Emb ryology 14th ed. Fig. 13.36 22  LO3 Septum Formation in Ventricles Medial walls expand forming muscular IV septum Membranous part of IV septum closes IV foramen Semilunar Valves – Small tubercles on main truncus swellings form – Upper surface of tubercle is hollowed out to form valves, influenced by neural crest cells Langman's Medical Emb ryology 14th ed. ©AK2023 23 LO4 Ventricular Septal Defects acyanotic 12/10,000 births occur in membranous or muscular portions associated with abnormal partitioning in conotruncal region ©AK2023 Langman's Medical Emb ryology 14th ed. Fig. 13.33 24 LO4 tetralogy of Fallot (9.6/10,000 births) cyanotic unequal division of conus due to anterior displacement of conotruncal septum associated with patent ductus arteriosus and pulmonary stenosis 1 3 2 ©AK2023 Langman's Medical Emb ryology 14th ed. Fig. 13.34 4 25 LO4 persistent truncus arteriosus (0.8/10,000 births) cyanotic conotruncal ridges fail to form, and no division of outflow tract occurs accompanied by defective IV septum ©AK2023 Langman's Medical Emb ryology 14th ed. Fig. 13.35 26  coarctation of the aorta (3.2/10,000 births) LO4 Arterial acyanotic lumen below origin of L subclavian is markedly narrow System caused by intima proliferations Defects preductal or postductal types high upper limb BP, low lower limb BP Langman's Medical Emb ryology 14th ed. Fig. 13.42 ©AK2023 27 LO4 Congenital Heart Anomalies Onset of Direction Type Examples Cyanosis of Shunt Acyanotic Cyanotic ©AK2023 28  Image Credit ©AK2023 29  LO5 Fetal Circulation Pathways A. Oxygenated blood Umbilical v. → ductus venosus → IVC → R atrium → oval foramen → L atrium → L ventricle → aorta → body tissues B. Deoxygenated blood Body tissues → SVC/IVC → R atrium → R ventricle → pulmonary trunk → ductus arteriosus → descending aorta → umbilical aa. ©AK2023 Langman's Medical Emb ryology 14th ed. Fig. 13.52 30 LO5 3 Circulatory Changes After Birth 4 1. Closure of umbilical aa. shortly after birth 2. Closure of umbilical v. and ductus venosus shortly after umbilical aa. 3. Closure of ductus arteriosus immediately after birth 4. Closure of oval foramen at first breath, completes by year 1 2 1 ©AK2023 Langman's Medical Emb ryology 14th ed. Fig. 13.53 31