Lecture 30 - Heart Development and Malformations Flashcards
Where do the first heart field cells (FHF cells) initially form a pair of tubes?
Within the visceral layer of lateral plate mesoderm
The heart tube initially consists of what two layers?
- Endocardium - inner epithelial layer
2. Myocardium - muscular layer
The inflow or venous pole of the heart tube is located posteriorly (caudally) and is the future ______ region.
atrial region
The outflow or arterial pole is located cranially, and it ultimately forms what three structures?
- RIGHT ventricle
- base of pulmonary trunk
- Ascending aorta
40-50% of children have heart defects, which may reflect abnormalities in _____ signaling.
Shh
Which septal defect has a molecular link to Pitx2?
Truncal septal defect
The embryonic precursor of the adult left ventricle are known as the _____.
First heart field cells (FHF)
By the end of the 4th week, looping has brought individual heart regions into adult-like positions. The embryonic circulatory system is remodeled to form the :
asymmetrical fetal circulatory system
The critical period for susceptibility to damage in the heart is:
5-9 weeks
Where are the endocardial cushions found?
the walls of the AV canal
Some of the heart conditions in children with Down Syndrome may reflect alterations in Shh signaling, including what two types of septation?
- AV canal septation
2. Atrial septation
After a prenatal ultrasound, a man and woman are told that their baby’s heart has a large overriding aorta, a defect in the membranous interventricular septum, and a stenotic pulmonary trunk. You are a friend of the couple and are asked by them what could have gone wrong developmentally. After discussing the case with their physician and reviewing your embryology notes, you tell them that:
A. The septum that normally divides the truncus arteriosus into a pulmonary and aortic trunk may have failed to form.
B. The septum that normally divided the truncus arteriosus into a pulmonary and aortic trunk is misaligned.
C. The septum that normally separates the two atria may have failed to form.
D. The inflow portion of the embryonic heart tube was not remodeled correctly.
E. The septum that normally divides the truncus arteriosus into a pulmonary and aortic trunk did not spiral as it normally should.
B.
One possible explanation for the coincidence of tracheal-esophageal and heart defects in children is:
a) BMPs are required for both septation of the trachea and esophagus as well as the formation of endocardial cushion tissue.
b) During embryogenesis, pharyngeal mesoderm contributes cells to both respiratory organs as well as the heart.
c) During embryogenesis, pharyngeal endoderm contributes cells to both respiratory organs as well as the heart.
d) Cranial neural crest cells make major contributions to both respiratory organs and the heart.
B.
