Cardio embryology Flashcards
What are the first signs of cardiovascular development in the embryo
Formation of blood Islands and myoblasts
Blood cell development first begins where
endothelial lined tubes then moves to the liver then to the bone marrow
First form of the heart?
Endothelial tube
What is the sinus venosus
Thats where blood from the placenta comes into the fetal heart, then goes to the unpartitioned atrium, unpartitioned ventricle, bulbus cortis
Truncus arteriosus develops into
Aorta and pulmonary trunk
Bulbus cortis turns into
The parts of the left and right ventricle inferior to the aorta and pulmonary trunk
primordial ventricle turns into
rt and left ventricle
Sinus venosus
left horn turns into coronary sinus, right horn into rt atrium
Does the atrium ever get fully partitioned during the fetal period?
No, because you want the blood flow to go from right to left and get into the systemic circulation without going through the undeveloped lungs
Ostium primum
opening between left and right atria
Describe developemnt of the atrial septa
As the septum primum grows down towards teh endocardial cushion, holes develop in its superior portion (ostium secundum) that allow blood flow to continue to flow from right to left atria even as the ostium primum closes
Foramen ovale
A hole in the septum secundum (a crescent shape septum that drops next to the septum primum) that allows blood to pass through the atrial septum
Changes in pressure after birth
Before birth, the right atrium is under very high pressure b/c of the blood flow coming in from the placenta. This pressure allows the blood to go through the foramen ovale to the right side. After birth, the placental flow stops. blood goes to lungs and then to left atrium so pressure reverses and is high on the left
What about the little bit of blood that makes its way to the right ventricle and tries to move into the lungs via the pulmonary trunk during prenatal life?
It is shunted through the ductus arteriosus which attaches the pulmonary trunk to the aorta.
Ventricular septum has a muscular portion and a membranous protion
true…membranous part comes from endocardial cushion…muscular part comes from a ridge in the myocardium
Left to right atrial shunt is caused by?
Excessive resorption of the septum primum or absence or septum secundum or potentially absence of both
Left to right atrial shunt leads to
Pulmonary hypertension. You get right atrial and ventricular overload that gets pumped to the lungs. Too much blood in the lungs
Ventricular septal defect almost always found where?
Membranous part of the septum
Left to right ventricular shunting can cause?
Cyanosis
Eisenmanger complex
When congenital defects lead to pulmonary hypertension and enlarged right heart usually due to a left to right shunt
Atrial defects lead to eilenmanger complex more slowly than ventricular
true
Septum that divides the aorta and pulmonary trunk comes from
neural crest cells…its a spiral septum, know that
Three conditions that cause cyanosis
Tetralogy of Fallot, transposition of the great vessesls, persistent truncus arteriosus
What is tetralogy of fallot
occurs when the aorticopulmonary septum shifts to the right and fails to alight properly. Results in pulmonary stenosis, overriding aorta, interventricular septal defect, right ventricular hypertrophy. Causes right to left shunting. Basically its a small pulmonary artery and a big aorta
Persistent Truncus
Occurs when there is only partial development of aorticopulmonary septum. Results in only one large artery leaving the heart and receiving blood from both ventricles. ALWAYS accompanied by a membranous ventricular septal defect
Transposition of the Great vessels
Baddddd…the aorta and pulmonary trunk are on the wrong sides. unoxygenated blood goes to circulation. incompatible with life unless you have some other defects like an open ductus arterosus or either atrial or septal defects
Patent ductus arteriosus
Open ductus, some blood from the aorta goes back into pulmonary trunk…leads to pulmonary hypertension
How many aortic arches connect the two dorsal aorta in development
6
Explain what happens to these 6 arches
5 never really develops, 1 and 2 disappear.
6 is the pulmonary trunk and pulmonary arteries, 4 is rt subclavian and aortic arch, 3 internal and external carotid
Riht recurrent laryngeal nerve dives underneath aortic arch, left gets cut off by ligamentum arteriosum so it has to go anterior of the aortic arch
true
With a preductal coarctation, the kid is ok as long as the ductus stays open
true…keep ductus open by infusing prostaglandins until the repair can be made
In a post ductal coarctation, kid is in trouble
true
Remember One umbilical vein persists and brings blood through the ductus venosus
true
Vitelline veins give rise to
right and left inferior vena cava, hepatic vein, portal vein….could be a test question
Pre-ductal coarctation, ductus remains open or shuts?
ductus remains open, this keeps blood supplying the body
Pst ductal coarctation, ductus shuts
truth
What do you do to keep the ductus open in a pre-ductal coarctation
Infuse prostaglandins
Liver grows into what veins?
Vitelline and umbillical
WHats the point of the ductus venosus
Bypasses sinusoids in the liver. Channels blood from umbillical veins to the IVC
Start with 2 unmilical veins, 2 viteline veins, liver develops, vitelline veins turn into IVC hepatics and portal, only one umbilical vein persists and it dumps straight into ductus venosus. SInusoids get bypassed
know
