Embryology | Development of the Heart ❤️
Ninja Nerd・2 minutes read
Heart development involves the formation of heart tubes and pericardial cavities, with mesoderm playing a crucial role. The process includes the formation of various heart structures like ventricles and atria, culminating in the completion of the heart formation process with the development of semilunar valves.
Insights
- Heart development involves the formation of a heart tube and pericardial cavity, with a critical role played by the mesoderm in the cranial aspect of the embryo.
- Vascular endothelial growth factor (VEGF) stimulates the lateral plate mesoderm to differentiate into heart tubes and blood cells, leading to the fusion of heart tubes and pericardial cavities.
- Neural crest cells migrate to form endocardial cushions, creating septations between the atria and ventricles, ultimately forming the left and right AV canals and completing the heart's structural development.
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Recent questions
How does the heart initially develop?
In the heart development process, the heart initially forms in the head region of the embryo before moving down into the thorax. This movement is crucial in understanding the cranio-caudal aspects of heart development.
What stimulates the lateral plate mesoderm in heart development?
Vascular endothelial growth factor (VEGF) plays a significant role in heart development by stimulating the lateral plate mesoderm to differentiate into heart tubes and blood cells.
What is the role of ectoderm and endoderm in heart development?
Ectoderm and endoderm release VEGF, which stimulates the mesoderm to form a heart tube and pericardial cavity. Additionally, ectoderm and endoderm start folding, pulling mesoderm caudally towards the neck area during development.
How does the heart structure change during cardiac looping?
The cardiac looping process involves the movement of various heart structures like the truncus arteriosus, bulbous cordis, primitive ventricle, primitive atria, and sinus venosus to form the heart structure. This process is essential in shaping the heart's final form.
What is the significance of septation in heart development?
After forming the heart tube and looping it, the next step is to develop septations to separate the atria and ventricles. This process involves the formation of right and left AV canals, leading to the development of valves and ensuring one-way blood flow within the heart.
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Summary
00:00
Heart development: from tube to cavity
- The heart development process involves the formation of a heart tube and pericardial cavity.
- The embryo's cranial and caudal aspects are crucial in understanding heart development.
- Mesoderm plays a significant role in heart development, particularly in the cranial aspect of the embryo.
- The heart initially develops in the head and then moves down into the thorax.
- Heart tube development is observed in cross-sectional and sagittal views.
- The heart tube forms from the splanchnic layer of the lateral plate mesoderm.
- Vascular endothelial growth factor (VEGF) stimulates the lateral plate mesoderm to differentiate into heart tubes and blood cells.
- Heart tubes and pericardial cavities develop from the lateral plate mesoderm.
- Fusion of heart tubes and pericardial cavities results in one heart tube and one pericardial cavity.
- The dorsal mesocardium connects the pericardial cavity to the heart tube, and the heart tube consists of endocardium and myocardium layers with cardiac jelly in between.
14:40
Heart Development: From VEGF to Pericardium
- Ectoderm and endoderm release VEGF, stimulating mesoderm to form a heart tube and pericardial cavity.
- Ectoderm and endoderm start folding, pulling mesoderm caudally towards the neck area.
- Embryo folds, moving the heart into the chest cavity during cranio-caudal folding.
- Pericardial cavities fuse, pulling the heart tube into the pericardial cavity during folding.
- Heart tube is examined in cross-sectional and sagittal views to understand its structure.
- Heart tube consists of outflow tracks, dorsal aorta, truncus arteriosus, bulbous cordis, primitive ventricle, primitive atria, and sinus venosus.
- Truncus arteriosus becomes the pulmonary artery and aorta, bulbous cordis becomes the right ventricle and outflow tracks.
- Primitive ventricle becomes the left ventricle, primitive atria become the left and right atrium, and sinus venosus receives blood from common cardinal, umbilical, and vitelline veins.
- Cardiac looping process involves movement of truncus arteriosus, bulbous cordis, primitive ventricle, primitive atria, and sinus venosus to form the heart structure.
- Sinus venosus contributes cells to form the visceral pericardium around the heart during development.
29:56
Heart Development in Utero: A Summary
- Transvaginal ultrasound can detect the formation of a primitive conduction system in the heart around week six of gestational development.
- The next step after forming the heart tube and looping it is to develop septations to separate the atria and ventricles.
- The goal is to form right and left AV canals between the atria and ventricles.
- Neural crest cells migrate and form endocardial cushions, which fuse to create the septum intermedium, separating the primitive atria and ventricles.
- The septum intermedium forms right and left AV canals, leading to the development of the mitral valve on the left side and the tricuspid valve on the right side.
- Valves, annular rings, and chordae tendineae are formed from the septum intermedium, ensuring one-way flow from the atria to the ventricles.
- The next step involves forming a right atrium and left atrium by developing the septum primum and septum secundum to separate the atria.
- The foramen ovale, a space between the septum secundum and ostium secundum, allows blood to bypass the lungs in utero, closing after birth.
- The completion of septation allows for the identification of the right atrium and left atrium.
- The final step is to separate the bulbous cordis and primitive ventricle, forming the muscular portion of the interventricular septum to create the left and right ventricles.
45:59
Development of Heart Structures in Embryos
- Tissue from the septum intermedium fuses with the muscular portion of the interventricular septum, forming the membranous portion.
- Failure of the membranous portion to meet the muscular portion results in a ventricular septal defect.
- The bulbous cordis becomes the right ventricle, while the primitive ventricle becomes the left ventricle.
- The bulbous cordis forms the right ventricle and the outflow track.
- Inflow tracks into the right atrium are developed from the primitive atria and sinus venosus.
- The left and right horns of the sinus venosus feed into the primitive atria, forming the coronary sinus and superior vena cava.
- The inferior vena cava is formed from the right vitelline vein.
- Neural crest cells form ridges in the truncus arteriosus and bulbous cordis, creating the aortico pulmonary septum.
- Blood from the left ventricle flows through the aortic arch, while blood from the right ventricle flows through the pulmonary trunk.
- The aortico pulmonary trunk structure rotates, separating into the aorta and pulmonary trunk.
01:01:56
Heart Development: Blood flow, structures, valves, positioning
- Blood flow pattern: Blood from the right ventricle moves up via the pulmonary trunk, going above the aorta and then underneath it, forming a distinct flow pattern.
- Formation of heart structures: The aorta and pulmonary trunk are formed, connecting to the ventricles to create the right atrium, left atrium, left ventricle, and right ventricle.
- Creation of outflow tracts: The outflow tracts from the right and left ventricles are formed via the bulbous cordis, leading to the pulmonary artery and aorta.
- Development of semilunar valves: Endocardial cushions are formed at the junction of the bulbous cordis and conus cordis, leading to the creation of semilunar valves for the aorta and pulmonary trunk.
- Rotation and positioning: Rotation occurs, positioning the aorta more posterior and on the right side, while the pulmonary trunk is more anterior and on the left side.
- Final heart structure: The pulmonary semilunar valves are formed in the right ventricular outflow tract, while the aortic semilunar valves are formed in the left ventricular outflow tract, completing the heart formation process.
