Development of the heart

What is the origin of the heart

* Mesoderm
* Splanchnic lateral Mesoderm

What make the mesoderm differentiate and proliferate

* VEGFs

→secreted by endoderm

Where the mesoderm differentiate and proliferate

near the buccopharyngeal membrane

Into What the mesoderm differentiate and proliferate

* 2 heart Tubes
* Outer layer → Angioblasts
* Inner Layer → Hemocytoblasts
* Dorsal Aortae
* Pericardial Cavities

what happen to heart tubes after embryo folding

* fuse together making 1 Heart Tube
* same the pericardial cavities

what connects pericardial cavity and heart tube

* Dorsal Mesocardium

Layers of heart tube

* Endocardium → angioblasts
* Myocardium → cardiac Myocytes

Myocardium secretes what substance

* Myocardiac Jelly

Parts of heart Tube

( superior - inferior)

* Aortic Sac
* Truncus Arteriosus
* Bulbus Cordis
* Primitive Ventricle
* Primitive Atrium
* Sinus Venosus

parts of Sinus Venosus

* Lt & Rt horns

part of each horn of Sinus Venosus

from lateral to medial

* Common Cardinal Vein s
* Umbilical vein
* Vitelline Veins

Derivatives of Truncus Arteriosus

* Ascending Aorta
* Pulmonary Trunk

Derivatives of Bulbus Cordis

* Rt Ventricle
* outflow parts of ventricles

Derivatives of primitive Ventricle

* Inflowing(Trabeculated) Parts of ventricles

Derivatives of Primitive Atrium

* Inflowing (trabeculated) Parts of Atria

Derivatives of SV

* visceral Pericardium
* Primitive Conducting System

Fate of left horn of SV + Rt umbilical vein

* Left horn → becomes coronary sinus
* Rt umbilical → degenerate

fate of RT Common Cardinal Vein

* SVC

Fate of Rt Vitelline Vein

* IVC

What cause cardiac looping

* Dynein (PTN)

Defect in left-right dynein cause ??

Dextrocardia

First functional organ

* Heart (4 th week)

What Happens in cardiac Looping

* TA + BC --------move → Downward to the right
* PV -→ left to midline
* PA → Posteriorly

Where does Neural Crest Cells migrate

Between Primitive Ventricle and atrium

What does Neural Crest Cells make

Endocardial Cushions

Outcome of endocardial cushion Fusion

* Septum Intermedium
* Rt & LT AV canals

Derivative of Septum Intermedium

* AV valves

\

What grows from the endocardium towards Septum Intermedium

* Septum Primum
* Does not reach it --→ Ostium Primum

What happens after Septum primum reaches Septum intermedium

* formation of Ostium Secundum at the top of SP
* cause Rt-Lt shunt

What happens after Septum Secundum grows in front of Ostium Primum

* Formation of Foramen Ovale

Origin of Mascular Part of IV septum

Apex of heart

Origin of Membranous Part of IV Septum

Septum Intermedium

What Migrate between Truncus Arteriosus and Bulbus Cordis(Outflow Tract) +

forming???

* Neural Crest cells
* Endocardial Cushion +

How many septum are formed by the endocardial cushions from of outflow tract

* 3
* they connect with each other forming one septum (Aortico-pulmonary septum)

Tract of blood pumped by Lt ventricle as Aortico-pulmonary septum is formed

under bulbus cordis septum → above truncus arteriosus septum

Tract of blood pumped by Rt ventricle as Aortico-pulmonary septum is formed

above bulbus cordis septum → under truncus arteriosus septum

What Migrate between Conus Cordis - Bulbus Cordis junction (Outflow Tract) +

forming???

* Neural Crist Cells
* 4 Endocardial Cushions

What happen While spiraling of Aortico-pulmonary septum

* Formation of Aorta and Pulmonary Trunk
* Invagination + separation of Endocarial Cushions of Conus Cordis - Bulbus Cordis junction → Semilunar Valves