The Cardiovascular System (Part I) 黃敏銓 解剖學暨細胞生物學研究所

Transcription

1 The Cardiovascular System (Part I) 黃敏銓 解剖學暨細胞生物學研究所 1

2 Congenital heart defects (CHDs) 台灣兒童心臟學會

3 Sinus venarum Membranous septum Conus arteiosus (infundibulum) Aortic vestibule

4 The Cardiovascular System 1. The first major system to function 2. The primordial heart and vascular system appear in the middle of the third week 3. The heart starts to function at the beginning of the fourth week 4

5 The cardiovascular system is derived mainly from: Splanchnic mesoderm Paraxial and lateral mesoderm Neural crest cells 5

6 Early development of the heart Heart primordium Angioblastic cord 18 days Angioblastic cord 6

7 Fusion of endocardial heart tubes Ventral views 7

8 Fusion of endocardial heart tubes Pericardial coelom 20-day Dorsal mesocardium Epicardium Cardiac jelly Primordial myocardium (from splanchnic mesoderm) 22-day 8

9 U-shaped bulboventricular loop Primordial atrium 有不同命名方式 Truncus arteriosus Sinus venosus Bulbus cordis Primordial ventricle 24 days 9

10 Circulation through primordial heart 6 Sinus venosus End of 4th week: unidirectional flow 4 10

11 Partitioning of primordial heart begins around middle of the 4th week. is completed by the end of the 8th week. includes partitioning of: Atrioventricular canal Primordial atrium Primordial ventricle 11

12 Partitioning of Atrioventricular Canal 5th week Fused endocardial cushions End of 4th week Endocardial cushions (from cardiac jelly) Left AV canal Transformed endocardial cushions also contribute to the formation of valves and membranous septa of the heart. 12

13 AV endocardial cushions Bone morphogenetic protein (BMP2) the primordia of the valves and membranous septa 13

14 Partitioning of primordial atrium begins at the end of the 4th week. is divided into right and left atria by: Septum primum Septum secundum 14

15 Septum primum Septum primum Endocardial cushion Septum secundum Foramen secundum (Ostium secundum) Foramen primum (Ostium primum) 15

16 Septum primum Septum primum Foramum primum Foramum primum Foramum secundum Foramum primum Septum secundum Foramum secundum Septum primum 16

17 Septum secundum Septum secundum (upper limb) 5th~6th week Foramen secundum Oval foramen Valve of oval foramen (from septum primum) Oval foramen Valve (from septum primum) 17

18 Valve of oval foramen Septum primum Oval foramen (open) Valve of oval foramen Septum secundum 18

19 Oval fossa is a remnant of oval foramen Before birth After birth Septum secundum Oval foramen Septum primum (valve of oval foramen) Oval fossa 19

20 Development of sinus venosus Left horn of sinus venosus Opening of sinus venosus into primordial atrium Right horn of sinus venosus Left Right Dorsal view (4 th week) 20

21 Progressive enlargement of the right horn results from two left-to-right shunts of blood Left Right Dorsal view (7 weeks) 21

22 Doral view Primordial atrium 26 days Right horn of sinus venosus Left horn of sinus venosus 8 weeks Sinus venarum of right atrium Coronary sinus Left Right 22

23 Right sinuatrial valve Crista terminalis Valve of IVC Valve of coronary sinus Left sinuatrial valve fused with septum secundum Interatrial septum Crista terminalis Valve of coronary sinus Right Left Valve of inferior vena cava 23

24 Absorption of pulmonary vein into left atrium 5 weeks 6 weeks Primordial pulmonary vein Primordial left atrium Smooth-walled part of left atrium Left auricle Right 8 weeks Left 24

25 The role of pulmonary veins in atrial fibrillation (Pharmacol Ther Nov;124(2): ) Pulmonary vein ablation 心房顫動 (atrial fibrillation) myocardial sleeves of pulmonary veins Cardiovasc Res (2002) 54 (2):

26 Bulbus cordis incorporates into the walls of ventricles Conus arteriosus (infundibulum) Aortic vestibule 26

27 Partitioning of primordial ventricle Fused endocardial cushions 5th week Interventricular foramen Interventricular septum (muscular part) Expansion Right Left 27

28 Membranous part of IV septum Membranous septum Aortic vestibule

29 Closure of the interventricular foramen Membranous part of IV septum Right bulbar ridge Left bulbar ridge Fused endocardial cushions 7 weeks 29

30 Cavitation of the ventricular walls forms a sponge-work of muscular bundles trabeculae carneae 5 weeks 6 weeks 20 weeks 7 weeks Chordae tendinae Right Trabeculae carneae Left Papillary muscle 30

31 Partitioning of Bulbus Cordis and Truncus Arteriosus Truncus arteriosus Truncal ridge Bulbus cordis 5 weeks Bulbar ridge Aorta Pulmonary trunk Aorticopulmonary septum 6 weeks 31

32 Spiral form of Aorticopulmonary Septum 32

33 Development of cardiac valves (semilunar valves) Swellings of subendothelial tissue Dorsal valve swelling Bulbar ridges Ventral valve swelling 33

34 Hollowing and thinning of valve swellings Valve swelling 34

35 Cardiac conduction system Sinus venosus Sinuatrial (SA) node (5 th week) Atrioventricular (AV) node Right Left Atrioventricular bundle Branches of AV bundle 35

36 Fetal circulation Ductus arteriosus Foramen ovale Ductus venosus Sphincter 36

37 Transitional Neonatal Circulation 1. Alteration of the lungs Fall in pulmonary vascular resistance Increase pulmonary blood flow Thinning of walls of pulmonary arteries 2. The oval foramen closes. Higher left atrium pressure Thicker left ventricular wall by the end of 1st month 3. The ductus arteriosus constricts. Close: Oxygen, bradykinin, indomethacin (PGE 2 inhibitor) Open: Hypoxia, PGE 2, prostacyclin (PGI2) 4. The umbilical arteries constrict. 37

38 Adult Derivatives of fetal vascular structures Ligamentum arteriosum (Ductus arteriosus) Oval fossa (Foramen ovale) Ligamentum venosum (ductus venosus) Ligamentum teres (umbilical vein) Superior vesical artery (umbilical artery, proximal) Medial umbilical ligament (umbilical artery, distal) 38