12 Questions
Where does the formation of the heart tube and pericardial cavity derive from?
Mesoderm
What connects the heart tube to the pericardial cavity during development?
Dorsal mesocardium
Which layer of the heart tube is made from cardiac myocytes that secrete cardiac jelly?
Myocardium
During development, what process leads to the fusion of two heart tubes and two pericardial cavities?
Lateral folding
Which structure allows blood flow from the sinus venosus to the dorsal aortae in the heart tube?
Truncus arteriosus
What moves the developing heart from the head into the thorax during development?
Lateral folding
What structure does the sinus venosus give rise to during early heart development?
Visceral pericardium
Which structure separates the primitive atria from the ventricles during heart development?
Septum intermedium
What can the absence of the membranous portion of the interventricular septum lead to?
Ventricular septal defect
Which veins contribute to the inflow tracts into the right atrium during heart development?
Umbilical veins
What structure separates the aorta from the pulmonary trunk, allowing for distinct blood flow patterns?
Aortico-pulmonary septum
Where does blood from the right ventricle flow through after leaving the heart?
Pulmonary trunk
Study Notes
- Development of the heart involves the formation of a heart tube and pericardial cavity from lateral plate mesoderm stimulated by growth factors like VEGF.
- The heart tube develops in the head region of the embryo and moves down into the thorax during development.
- The heart tube is suspended in the pericardial cavity by the dorsal mesocardium, which connects them.
- The heart tube consists of layers: endocardium (inner layer) made from angioblasts and myocardium (outer layer) made from cardiac myocytes secreting cardiac jelly.
- During lateral folding, two heart tubes fuse to form one heart tube, and two pericardial cavities fuse to form one pericardial cavity.
- Cranio-caudal folding moves the developing heart from the head into the thorax, with the heart tube getting stuffed into the pericardial cavity.
- The heart tube consists of various vesicular portions: truncus arteriosus, bulbous cordis, primitive ventricle, primitive atria, and sinus venosus.
- Blood flows through the heart tube from the sinus venosus to the dorsal aortae via specific structures like the truncus arteriosus and primitive ventricle.
- Specific portions of the heart tube develop into different structures in the adult heart: truncus arteriosus becomes pulmonary artery and aorta, bulbous cordis becomes right ventricle and outflow tracks, etc.- The structure below the primitive atria is called the sinus venosus, which receives inflow from three different tracts: common cardinal veins, umbilical veins, and vitelline veins.
- Blood enters the sinus venosus through the right and left horns, with the same veins entering both horns.
- Cardiac looping is a crucial process that depends on dynein proteins; abnormalities in this process can lead to conditions like dextrocardia and situs inversus.
- During cardiac looping, the truncus arteriosus and bulbous cordis move downward and to the right initially.
- As cardiac looping progresses, the primitive ventricle moves to the left of the midline while the truncus arteriosus and bulbous cordis continue moving down and to the right.
- The primitive atria move backwards and upwards during cardiac looping, forming the right and left atria eventually.
- The sinus venosus gives rise to the visceral pericardium and a primitive conduction system in early developmental stages.
- Endocardial cushions formed by neural crest cells fuse to create the septum intermedium, separating the primitive atria from the ventricles and forming right and left AV canals.
- The septum primum grows towards the septum intermedium, creating a space known as the ostium primum in the atrial septum.
- The septum primum eventually reaches and fuses with the septum intermedium, forming a new hole called the ostium secundum above it.- The heart development process involves the formation of various structures such as the left atrium, right atrium, left ventricle, right ventricle, right AV canal, and left AV canal.
- The septum intermedium develops at the apex of the heart, leading to the formation of the muscular portion of the interventricular septum and the membranous portion of the interventricular septum.
- The membranous portion of the interventricular septum is crucial as its absence can lead to a ventricular septal defect.
- Inflow tracts into the right atrium are formed from the fusion of different veins like common cardinal veins, umbilical veins, and vitelline veins.
- The left horn develops into the coronary sinus, while the right horn contributes to the formation of the superior vena cava and the inferior vena cava.
- The formation of the aortico-pulmonary septum separates the aorta and pulmonary trunk, allowing for distinct blood flow patterns.
- The formation of ridges at the truncus arteriosus and bulbous cordis leads to the development of the aortico-pulmonary septum in a corkscrew fashion.
- Blood flow from the left ventricle travels through the aortic arch, while blood from the right ventricle flows through the pulmonary trunk.
- The rotation of the aortico-pulmonary trunk structure results in separate pathways for blood flow from the left and right ventricles.
- The formation of endocardial cushions at the bulbous cordis and conus cordis junction leads to the development of semilunar valves for directing blood flow into the aorta and pulmonary trunk.
Test your knowledge on the intricate process of heart development in embryos, from the formation of heart tubes to the development of structures like atria, ventricles, and septums. Explore how blood flows through the developing heart and how crucial processes like cardiac looping and endocardial cushion formation shape the future heart anatomy.
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