CV System Embryology 1 Flashcards
What embryological layer does the heart arise from?
Mesoderm. Mesoderm also gives rise to skeletal muscle, red blood cells, and other smooth muscles.
The heart and the great vessels come from what cell line?
The mesenchymal cells in the cardiogenic area. Mesenchymal cells are multipotent stem cells that can differentiate into various cell types (like myocytes, adipocytes, and osteoblasts).
At what point do vasculogenesis and angiogenesis, blood vessel development, begin?
At the beginning of the third week.
Where does vasculogenesis and angiogenesis happen?
In the extraembryonic mesoderm of the yolk sac, allantois, and chorion. Mesoderm gives rise to new vessels and heart structures.
How does the heart tube form?
2 endothelial-lined channels, known as the endocardial heart tubes, fuse together to form the heart tube
By the end of the third week what does the primordial cardiovascular system look like?
The heart is represented by the heart tubes and is joined by blood vessels from the embryo and extraembryonic membrane
The superior vena cava is developed out of what structure?
The right anterior cardinal vein and the right common cardinal vein
What 4 main segments compose the inferior vena cava?
(1) hepatic segment; from the hepatic vein and sinusoids
(2) prerenal segment; from the right subcardinal vein
(3) renal segment; from the subcardinal-supracardinal anastomosis
(4) postrenal segment; from the right supracardinal vein
From what does the aorta and the pulmonary trunk develop?
(1) The bulbar ridges fuse and become an aorticopulmonary septum
(2) This aorticopulmonary septum then divides the bulbus cordis and the truncus arteriosus into 2 arterial channels
(3) These 2 channels become the aorta and the pulmonary trunk
The aorta and the pulmonary trunk are formed when in gestation?
Between week 5 and 6
At what point can a fetal heart beat be detected by a Doppler heart monitor?
7 weeks after the last known menstrual period, also known as week 5 in fertilization age terms
Fetal circulation happens in what order?
(1) The umbilical vein delivers oxygenated blood
(2) After bypassing the liver, the blood moves from the ductus venosus into the IVC and the right atrium
(3) It enters the left atrium and ventricle through the foramen ovale
(4) It enters the pulmonary trunk at the same time via the ductus arteriosus
(5) After it enters the lung and the peripheral body through the aorta, it is passed back to the placenta due to the umbilical arteries
The embryonic foramen ovale becomes what after birth?
Fossa ovalis. Once the respiratory circulation begins after birth, the pressures between the atria bring the septum primum up against the septum secundum. This turns the foramen ovalis (shunt) into the fossa ovalis (depression in the heart wall).
The embryonic ductus arteriosus becomes what after birth?
Ligamentum arteriosum. The ductus arteriosus shunted blood from the pulmonary trunk into the aorta. Once the lungs take over circulation at birth, it is no longer needed and becomes a ligament.
What forms the atria?
The separation into right and left of the primitive sinuatrium or septum primum. The septum primum divides the primitive atrium into right and left parts.
