Transcript Circulation system

Development of the
circulation system
陳建榮
http://web.nchu.edu.tw/pweb/users/chenjr/
Midgut development of animals
Normal development of circulation system
-Early Events
-Migration of cardiogenic mesenchyme
-Differentiation of mesenchyme
-Chamber formation
-Folding of the heart tube
-Critical Changes
-Vascular Changes
Migration of cardiogenic mesenchyme
血管母細胞索
血管母細胞索
Differentiation of mesenchyme
The early heart is a simple tube which commences beating during the third
week (Day 21-22).
Cardiogenic mesenchyme differentiates into three distinct cell populations:
-Endocardium 心內膜
-Myocardium 心肌
-Epicardium 心外膜
Cell Population
Endocardium
Myocardium
Epicardium
Functions and Fates
Endothelial lining
Connective tissue precursor (Valves and fibrous skeleton)
Myocytes
Conduction system (Purkinje fibres)
Myoendocrine cells (Atrial Natriuretic Factor production)
Coronary vessel precursors
Visceral pericardial lining
SA node, AV node  mesoderm
Early heart chambers
Sinus venosus (SV)
靜脈竇
This is the collecting compartment of the heart.
Oxygenated blood from the placenta and
deoxygenated blood from embryonic tissues are
mixed in the sinus.
Primitive atrium (PA)
心房原基
This is the compartment destined for further partition
to the definitive atria.
Primitive ventricle (PV)
心室原基
This is the compartment destined for further partition
to the definitive ventricles.
Bulbus cordis (BC)
心球
This will contribute to the pulmonary trunk and aorta,
along with the truncus arteriosus.
Truncus arteriosus (TA)
動脈幹
This will contribute to the aortic arches.
Fibrous skeleton (FS)
纖維骨架
This is the area of connective tissue proliferation, site
of future valves.
Folding of the heart tube
Apoptosis in the dorsal mesocardium will allow movement of the
early heart tube within the pericardial cavity
Ant.
Post.
Normal development of Heart
-Early Events
-Critical Changes
-Endocardial cushion（心內墊） growth and fusion
-Bulboventricular looping 動脈球心室環
-Interatrial septum（心房間隔） formation
-Interventricular septum（心室間隔） formation
-Aortico-pulmonary septum（主肺動脈隔） formation
-Vascular Changes
Endocardial cushion心內墊 fusion
Endocardial cushions are areas of the fibrous skeleton forming between the atrium
and ventricle.
Endocardial cushions serve two important functions:
-form a partition in the heart tube between the atrium (PA) and ventricle (PV)
(tricuspid and bicuspid valves)
-provide a "scaffold" of the interatrial septae and the interventricular septum
Defects in endocardial cushion fusion are associated with trisomies 18 and 21 (Down's syndrome).
Clinical problems
Valvular atresia 房室瓣閉鎖
Valvular atresias arise from the uneven partition of the AV canal. Depending on the size and
position of the narrowed channel, a tricuspid atresia or a biscuspid atresia results. Atresias
arising from anomalous partition of the canal are referred to as congenital atresias
The folding of the heart tube brings the inflow and outflow trunks in an adjacent
position at the superior aspect of the developing heart.
The dorsal fold forms the two pericardial sinuses and places
the fibrous skeleton in a single plane
Inflow and outflow trunks are positioned posteriorly as a result of the dorsal fold
Bulboventricular loop動脈球心室環
Bulboventricular looping動脈球心室環
BV looping is a consequence of several changes:
- Dorsal folding
The first dorsal fold forms an expanded primitive ventricle, referred to as the bulboventricular loop.
- Ventricular growth
Differential growth of the proximal ventricular tissue causes a counter-clockwise rotation of the folded heart
tube. The site of ventricular growth marks the future left ventricle. Abnormal growth of the distal primitive
ventricle causes clockwise rotation, an anomaly known as dextrocardia心偏右.
- AV canal房室管 partitioning
The Atrio-Ventricular (AV) canal between the primitive atrium and ventricle has now been partitioned by the
fusing endocardial cushions.
- Shunting of venous return
The development of the venous system causes an increase in right-sided venous return to the primitive
atrium. Combined with the partitioning of the AV canal, the change in blood flow volume and directions
assists in the outgrowth of the left ventricle.
Dextrocardia 心偏右
Clinical problems
Looping anomalies(dextrocardia心偏右)
Bulboventricular looping動脈球心室環
BV looping is a consequence of several changes:
- Dorsal folding
The first dorsal fold forms an expanded primitive ventricle, referred to as the bulboventricular loop.
- Ventricular growth
Differential growth of the proximal ventricular tissue causes a counter-clockwise rotation of the folded heart
tube. The site of ventricular growth marks the future left ventricle. Abnormal growth of the distal primitive
ventricle causes clockwise rotation, an anomaly known as dextrocardia心偏右.
- AV canal房室管 partitioning
The Atrio-Ventricular (AV) canal between the primitive atrium and ventricle has now been partitioned by the
fusing endocardial cushions.
- Shunting of venous return
The development of the venous system causes an increase in right-sided venous return to the primitive
atrium. Combined with the partitioning of the AV canal, the change in blood flow volume and directions
assists in the outgrowth of the left ventricle.
Interatrial septum formation
Blue arrows - direction of growth;
Red arrow - direction of blood flow;
ECC - endocardial cushion;
RA - right atrium;
LA - left atrium.
原隔
原孔
次孔
次隔
Fossa ovalis卵圓窩
Clinical problems
Atrial septal defects心房間隔缺損 (ASD)
Atrial septal defects (ASD) are fairly common, present in 10-15% of
patients with congenital cardiac anomalies. It is more commonly
observed in females than males (2-3:1).
Atrium septum defects (ASD)
Formation of left atrium
Interventricular septum formation
球狀脊
AP - aorticopulmonary主肺動脈幹;
ECC - endocardial cushion心肉墊;
Blue arrow - direction of bulbar ridge growth;
Red arrow - direction of ventricular growth
IVS Part
Origin
muscular
ventricular wall
membranous
fused bulbar ridges 球狀脊
fused endocardial cushions
球狀脊
室間孔
Clinical problems
Ventricular septal defects心室間隔缺損(VSD)
Atrioventricular septum defect房室瓣缺損
Aortico-pulmonary septum formation
The aortico-pulmonary (AP) septum主肺動脈間隔arises within the
truncus arteriosus. The septum results from the downwards growth and
fusion of bulbar ridges, induced by invasion of neural crest cells. The AP
septum serves to divide the ventricular outflow between the pulmonary
artery and the ascending aorta
球狀脊
Semilunar valve半月瓣
Clinical problems
Aortic stenosis and atresia動脈瓣膜狹窄、閉鎖
Tetralogy of Fallot (法樂氏四重畸形 )
The tetralogy of Fallot results from the asymmetric division of the AP
septum. The result is a stenosed pulmonary artery and a VSD.
Tetralogy of fallot:
-Pulmonary valve stenosis
-Ventricular septal defect
-Overriding aorta
-Hypertrophy of right ventricle
Eisenmenger's syndrome(森曼格綜合症)
Characteristics of Eisenmenger's syndrome:
-persistent truncus arteriosus
-ventricular septal defect
-left-right ventricular shunt
-right ventricle hypertrophy
Normal development of Heart
-Early Events
-Critical Changes
-Vascular Changes
-Overview of embryonic circulatory system
-Venous development
-Arterial development
-Anatomical correlations
Overview of embryonic circulatory system
Venous system development
Venous system development
Clinical problems
Persistent left superior vena cava
Arterial system development
Aortic arch derivation:
-1st pair of aortic arches: maxillary a.
-2nd pair of aortic arches: stapedial a.
-3rd pair of aortic arches: common carotid a. and int. carotid a.
-4th pair of aortic arches:
-Left  aortic arch
-Right  subclavian a.
-5th pair of aortic arches:
-6th pair of aortic arches:
-Left  left pulmonary a., ductus arteriosus
-Right  right pulmonary a.
Aortic arch derivatives
動脈韌帶
動脈導管
Aortic arch derivatives
動脈韌帶
動脈導管
Recurrent laryngeal n. and 6th aortic arch
Clinical problems
Anomalies of aortic arch
Double aortic arch
Normal
Right arch of aorta
Anomalies of right
subclavian artery
Clinical problems
Right arch of aorta
Double aortic arch雙主動脈弓
Anomalies of right subclavian artery
Anatomical correlations
Portacaval shunt門脈分流
= portasystemic shunt
Clinical problems
Porto-systemic (porta-cava) shunt
Intrahepatic porto-systemic shunt
Extrahepatic porto-systemic shunt
Ductus arteriosus動脈導管
Persistent Ductus arteriosus
Patent ductus arteriosus
Blue-pulmonary trunk; Red-aorta and tributaries; Green-patent ductus arteriosus
PDA Closure Device Surgery
Embryologic Structure
Adult Equivalent
Left anterior cardinal vein
disappears proximally
distal portion contributes to Left superior intercostal vein
anastomoses with Right anterior cardinal vein distally to form Left brachiocephalic vein
Left common cardinal vein
oblique vein of left atrium
Left posterior cardinal vein
disappears
Left horn of sinus venosus
coronary sinus
Right anterior cardinal vein
 superior vena cava
Right common cardinal vein
superior vena cava
Right posterior cardinal vein
azygous vein
Primitive atrium
right auricle
Foramen ovale
fossa ovalis and limbus
First aortic arch
maxillary artery
contribution to external carotid artery
Second aortic arch
 persists dorsally as stapedial artery
Third aortic arch
proximal portions form common carotid artery
distal portions form internal carotid artery
Fourth aortic arch
left arch (with aortic sac) forms ascending aorta and arch
right arch contributes to right subclavian artery
Fifth aortic arch
 does not persist
Sixth aortic arch
proximal left arch - left pulmonary artery
distal left arch - ligamentum arteriosum
proximal right arch - right pulmonary artery
distal right arch - does not persist
Ductus venosus
ligamentum venosum
Left umbilical vein
ligamentum teres distally
degenerates proximally
portion within septum transversum contributes to hepatic portal system
Right umbilical vein
degenerates proximally and distally
portion within septum transversum contributes to hepatic portal system
Left vitelline vein
fuses with right vitelline vein to form portal vein
Right vitelline vein
fuses with left vitelline vein to form portal vein
Development of lymphatic system
Lymph sac淋巴囊
-2 jugular lymph sac頸淋巴囊
-1 retroperitoneal lymph sac腹膜後淋巴囊
-1 cisterna chyli乳糜池
-2 iliac lymph sac髂淋巴囊