1.2.2 Development of Heart and Cardiovascular System Flashcards
When does the heart first beat in embryological development?
Day 22
List the most common congential anamolies.
VSD - 42%
ASD - 10%
Pulmonary stenosis - 7%
PDA - 7%
Tertralogy of Fallot - 5%
Aortic valve stenosis - 4%
Atrioventricular septal (canal) defect - 4%
TGA - 4%
Persistent truncus arteriosus - 1%
At day 20, when the embryo begins to fold both cranially on itself and medially, what structures are being formed?
- Cranial fold starts the formation of the aortic arch
- right and left endocardial tubes start to come towards each other
- endocardial tubes are developing adjacent to fluid filled sack, the pericardial cavity
At day 21, the fusion of the right and left endocardial tube in the cardiogenic region leads to the formation of what?
a single heart tube
Draw the pericardial sac at day 21-22.
Include aortic sac, bulbis cordis, ventricle, atrium, sinus venosus
Describe how the pericardial sac twists and folds into the heart structure.
At day 22 the heart starts to beat, what are the four layers of the heart at this point?
- Endocardium (primitive endocardium)
- Cardiac jelly (ECM)
- Myocardium (heart muscle)
- Epicardium (visceral pericardium)
The breakdown of what structure leads to the formation of the transverse pericardial sinus?
Dorsal mescardium
Another image of how the heart tube twists into form.
Typically twist to the left.
In what two conditions is the base of the heart directed to the right side of the body as opposed to the left? What differentiates the two conditions?
Dextrocardia (1/12,000 births) - increased risk of additional heart defects
Situs Inversus - all organs are completely reversed (1/7000 births) - only slight increased risk of additional heart defects
What helps form the septum intermedium (which helps separate atrium from ventricles)?
Endocardial cushions (posterior and anterior), Day 28
Abnormalities in endocardial cushions can lead to what type of defects?
ASD, VSD, AV canal defects, and TGA
What type of cells contribute to the cells that form the endocardial cushion?
Neural crest cells
People who have a variety of craniofacial defects are at greater risk of having endocardial cushion defects. What condition could lead to increased risk of atrioventricular septal (canal) defects?
Trisomy 21, Downs
What is believed to impair/inhibit neural crest cell migration?
Binge drinking alcohol
What causes atrioventricular septal (canal) defects? What is true about the four chambers of the heart?
Endocardial cushion defect; no separation of the four chambers