development of cardiovascular system (special embryology)

CARDIOVASCULAR SYSTEM

HEART(Page 115)

Dr.Sherif Fahmy

Anatomy of Heart

Dr.Sherif Fahmy

Dr.Sherif Fahmy

Dr.Sherif Fahmy

Dr.Sherif Fahmy

Dr.Sherif Fahmy

Dr.Sherif Fahmy

Dr.Sherif Fahmy

Development of the Heart

Dr.Sherif Fahmy

Dr.Sherif Fahmy

Dr.Sherif Fahmy

2 endocardial tubes

Dr.Sherif Fahmy

Dr.Sherif Fahmy

Dorsal aortae

Aortic sac

Heart tube Pharynx

Dr.Sherif Fahmy

Dr.Sherif Fahmy

Bulbo-ventricular sulcus

Dr.Sherif Fahmy

Sinus Venosus(Page 117)

Dr.Sherif Fahmy

Anterior ViewDr.Sherif Fahmy

Dr.Sherif Fahmy

Dr.Sherif Fahmy

Dr.Sherif Fahmy

Internal ViewDr.Sherif Fahmy

Dr.Sherif Fahmy

Dr.Sherif Fahmy

Dr.Sherif Fahmy

Absorption of Pulmonary vein

Dr.Sherif Fahmy

Dr.Sherif Fahmy

Dr.Sherif Fahmy

Dr.Sherif Fahmy

Dr.Sherif Fahmy

Development of Atria(Page 119)

Dr.Sherif Fahmy

Right & left atria are developed from:1- Primitive atrium of the heart tube.2- Absorption of sinus venosus.3- Absorption of pulmonary vein.4- Absorption of atrio-ventricular canal.5- Formation of inter-atrial septa.

Dr.Sherif Fahmy

Formation of Interatrial Septa

1- Septum primum.2- Septum secundum.3- Septum intermedium.

Dr.Sherif Fahmy

Dr.Sherif Fahmy

Dr.Sherif Fahmy

Septum secundum

Dr.Sherif Fahmy

Dr.Sherif Fahmy

Dr.Sherif Fahmy

Dr.Sherif Fahmy

DEVELOPMENT OF HEART• Heart primordium: • Two endocardial tubes are formed in the mesoderm

between buccopharyngeal membrane and cranial part of intraembryonic coelom (cardiogenic area).

• Fusion between the endocardial tubes to form a single tube.

• Mesoderm that surrounds the tube is called myo-epicardial mantle which forms myocardium of the heart.

• After folding, heart tube with the mantle will lies ventral to pharynx in pericardial bulge.

• The cranial (arterial) end is fixed with arteries of the fetus, while the caudal (venous) end is fixed to veins of the fetus.

• Elongation of the tube leads to formation of U-shaped tube.

Dr.Sherif Fahmy

Chambers of the heart tube:

-Three constrictions are formed in the tube will form 4 chambers:

Sinus venosus, Primitive atrium, Primitive ventricle and Bulbus cordis.

-Elongation of the tube leads to formation of U-shaped tube.

-More elongation of the tube leads to formation of S-shaped tube.

-Sinus venosus comes caudal to primitive atrium which is dorsal to primitive ventricle. Bulbus cordis on the right of primitive ventricle.

-Sinus venosus, pulmonary vein and primitive atrium will form the common atrium which is divided into right and left atria.Primitive ventricle with proximal part of bulbus cordis will form right and left ventricles, while distal part (truncus arteriosus) will form ascending aorta and pulmonary trunk.

Dr.Sherif Fahmy

Sinus Venosus• It is the cuadal chamber of heart tube that is formed of

body and 2 horns; each horn receives 3 veins (vitelline, umbilical and common cardinal vein).

• The body joins the back of right side of primitive atrium by sinu-atrial orifice which is guarded by right and left valves. While back of left side of primitive atrium is joined by pulmonary vein.

• Left sinus horn becomes reduced in size due to degeneration of left vitelline and umbilical veins as well as shift of blood from left anterior cardinal to right anterior cardinal by an anastomosis (becomes left brachiocephalic vein. Left horn remains as coronary sinus.

Dr.Sherif Fahmy

Absorption of body of sinus venosus:

-Body of sinus venosus and right horn are absorbed by widening of sinu-atrial orifice to form sinus venarum of right atrium.

-Cranial ends of 2 valves fuse together to form septum spurium that forms upper part of crista terminalis. Left valve will fuse with interatrial septum while right valve forms rest of crista as well as valves of inferior vena cava and coronary sinus.

-Absorption of pulmonary vein:

-Pulmonary vein has 2 divisions and each has 2 more divisions. Absorption will form wall of left atrium and 4 pulmonary veins will open separately to the left atrium. It forms the smooth part of the wall of left atrium.

Dr.Sherif Fahmy

Formation of Interatrial Septum• 1- Septum primum:• Crescentic septum that downgrows from the roof of

common chamber.• It is separated from atrio-ventricular canal by osteum

primum. More downgrowth will close the osteum primum while the upper part degenerates to form osteum secundum.

• 2- Septum secundum:• -Downward growth of crescentic septum secundum to the

right side of septum primum to cover osteum secundum which becomes foramen ovale.

• 3- Septum intermedium:• It is formed by fusion between ventral and dorsal atrio-

ventricular cushions to separates between right and left atrio-ventricular orifices. Dr.Sherif Fahmy

Development of Right Atrium

• It is developed from:• -Primitive atrium: forms rough anterior (musculi

pectinati) wall and auricle of right atrium.• -Sinus venosus: forms posterior smooth wall of

right atrium (sinus venarum).• -Right ½ of atrio-ventricular canal: forms right

atrioventricular orifice, inside which 3 cusps are formed (tricuspid valve).

• -Rt & Lt sino-atrial valves remain as crista terminalis and valves of inferior vena cava and coronary sinus.

Dr.Sherif Fahmy

Development of Left Atrium

• It is developed from:• 1- Primitive atrium: forms rough part of

left atrium in the left auricle (musculi pectinati).

• 2- Pulmonary trunk: absorped to form the smooth wall of the left atrium.

• 3- Left ½ of atrio-ventricular canal: forms the left atrio-ventricular orifice in which 2 cusps are developed. Dr.Sherif Fahmy

Anomalies of Interatrial Septum:1- Patent foramen ovale.2- Premature closure of foramen ovale.3- Probe patent foramen ovale.4- Osteum secondum defect.5- Agenesis of interatrial septum.Anomalies of atrio-ventricular canal:1- Persistent A-V canal.2- Osteum primum defect.3- Tricuspid atresia.

Dr.Sherif Fahmy

Dr.Sherif Fahmy

Development of Ventricles

(Page 125)

Dr.Sherif Fahmy

Anatomy of Ventricles and Related Arteries

Dr.Sherif Fahmy

Infundibulum

Inflow part

Pulmonary valve

Tricuspid valve

Dr.Sherif Fahmy

Muscular part

Membranous part

Dr.Sherif Fahmy

Development of Ventricles:Sources:1- Primitive ventricle form most of left ventricle and inlet of right ventricle.2- Proximal portion of bulbus cordis forms most of right ventricle.3- Midportion (Conus Cordis) of bulbus cordis forms the outflow parts of both ventricles.

Dr.Sherif Fahmy

Dr.Sherif Fahmy

Upper crescentic margin of intermuscular septum

Right auricle

Inferior A/V endocardial cushion

Conus septum

Lt. ventricle

Rt Ventricle

Dr.Sherif Fahmy

Bulbo-ventricular sulcus

Dr.Sherif Fahmy

Steps of Formation of Ventricles• Bulbus cordis lies to the right of primitive

ventricle then becomes ventral to it.• -Proximal part of bulbus cordis enlarges to

form right ventricle. The mid-prtion will form outflow part of each ventricle. The distal part forms truncus arteriosus (ascending aorta and pulmonary trunk).

• -Conus cordis is divided by Conus septum which is formed by fusion between right & left bulbar ridges.

Dr.Sherif Fahmy

Formation of interventricular septum:1- Muscular part developed by: -Upward growth from floor by proliferation of myoblasts.-Dilatation of both ventricles.2- Membranous part: developed by migrated cells from:

-Atrio-ventricular cushions.-Lower part of bulbar ridges.

Anomalies of interventricular septum:1- Septal defect in muscular or membranous part.

2- Complete absence of the septum.Dr.Sherif Fahmy

Fate of bulbus cordis1- Proximal part: forms most of right ventricle.

2- Mid-portion (Conus cordis): forms outflow parts of both ventricles.

3- Distal part (truncus arteriosus): forms orifices and main parts of ascending aorta and pulmonary trunk.

Dr.Sherif Fahmy

Conus septum

Rt Ventricle

Aortico-pulmonary septum

Truncus Arteriosus

Muscular part of interventricular septum

Dr.Sherif Fahmy

Formation of Aortico-pulmonary Septum

Dr.Sherif Fahmy

Dr.Sherif Fahmy

Spiral aortico-pulmonary septum

Upper crescentic margin of intermuscular septum

Dr.Sherif Fahmy

Dr.Sherif Fahmy

Anomalies of Bulbus Cordis

Fallot’s Tetralogy: due to anterior displacement of aortico-pulmonary septum. is manifested by pulmonary stenosis, overriding aorta, ventricular septal defect and hypertrophy of right ventricle.Persistant truncus arteriosus: due to failure of formation of bulbar cushions. It is usually accompanied with membranous ventricular septal defect.Transposition of great arteries (TGA): Aorta arise from right ventricle while pulmonary trunk arises from left ventricle due to loss of spiral shape of the septum.

Dr.Sherif Fahmy

Cardiac valves: (Page 129)1- Aortic & Pulmonary: from Subendocrdial swelling developed from migrated neural crest cells. Hollow up to those swellings lead to formation of semilunar valves.2- Tricuspid & Mitral: At A/V canal by formation subendocardial swellings (cushions).

Dr.Sherif Fahmy

Anomalies in the valves

Pulmonary and aortic stenosis: -Narrowing of aortic and pulmonary orifices due to fusion of their cusps.

Tricuspid atresia:

-Tricuspid atresia due to fused cusps.

Dr.Sherif Fahmy

Anomalies of position of heart-Ectopia cordis: defective formation of chest wall with external exposure of the heart.

-Dextrocardia: The heart is rotated to the right.

Dr.Sherif Fahmy

Anomalies of the Heart

Dr.Sherif Fahmy

Anomalies of Interatrial Septum:1- Patent foramen ovale.2- Premature closure of foramen ovale.3- Probe patent foramen ovale.4- Osteum secondum defect.5- Agenesis of interatrial septum.Anomalies of atrio-ventricular canal:1- Persistent A-V canal.2- Osteum primum defect.3- Tricuspid atresia.

Dr.Sherif Fahmy

Anomalies of interventricular septum:1- Septal defect in muscular or membranous part.

2- Complete absence of the septum.

Dr.Sherif Fahmy

Anomalies of Bulbus Cordis

Fallot’s Tetralogy: due to anterior displacement of aortico-pulmonary septum. is manifested by pulmonary stenosis, overriding aorta, ventricular septal defect and hypertrophy of right ventricle.Persistant truncus arteriosus: due to failure of formation of bulbar cushions. It is usually accompanied with membranous ventricular septal defect.Transposition of great arteries (TGA): Aorta arise from right ventricle while pulmonary trunk arises from left ventricle due to loss of spiral shape of the septum.

Dr.Sherif Fahmy

Anomalies in the valves

Pulmonary and aortic stenosis: -Narrowing of aortic and pulmonary orifices due to fusion of their cusps.

Tricuspid atresia:

-Tricuspid atresia due to fused cusps.

Dr.Sherif Fahmy