cardiovascular embryology Flashcards
name the three cardiac cell progenitors
- primary and secondary heart field (known collectively as the cardiac crescent)
- cardiac neural crest cells
where is the cardiac crescent found?
cranial end of trilaminar embryo on mesoderm layer (lateral plate mesoderm)
when does the cardiac crescent develop?
day 15-16
what do the PHF form?
heart tube (main structures of the heart) - around 22 days
- L ventricle and most of the 2 artia
what do the SHF do?
add to heart - R ventricle and little of the atria
what do the CNCCs do?
migrate from neural tube to heart tube, contributing to septa and vessels
what happens simultaneously with heart tube development?
embryonic folding, resulting in the developing heart being located in the ventral part of the now 3D embryo
what does the notochord do?
tell mesoderm to differentiate into lateral plate mesoderm
when do NCC arise?
day 18-19
label this diagram of the blind-ended heart tube on day 20 and describe what happens during its formation
- heart tube arises from cardiac crescent mesoderm
- simulatenously, the surrounding lateral plate mesoderm and intraembronic coelom (body cavity) form the pericardial membrane and pericardial cavity respectively
- the pericardium continues to surround the heart in the adult
label this diagram of the differentiated heart tube on day 20
label this diagram of the structures formed during further differentiation of the heart on day 21
when does folding of the heart occur?
day 21 - 35
how do SHF progenitor cells contribute to development of the heart tube?
inflow and outflow regions of developing heart tube
how can defects in CNCC cells cause genetic defects?
defects can cause them to not migrate and adhere properly to the heart, meaning certain structures won’t be developed properly
define foramen ovale
foetal cardiac shunt in the foetal atrial septum that permits blood to flow from the sinus venosus and right atrium to the left atrium
what happens to the foramen ovale at birth?
closes and forms the fossa ovalis in the walls of the right and left atria
how can the failure to close foramen ovale at birth causes CHD?
an atrial septal defect (ASD) termed patent foramen ovale (PFO), which permits the mixing of high oxygen blood in the left atrium and low oxygen blood in the right atrium
define ductus arteriosus
a foetal cardiac shunt that permits blood to flow from the foetal pulmonary artery to the aorta, thereby bypassing the foetal lungs
what happens to the ductus arteriosus?
closes and forms the ligamentum arteriosum, an embryonic remnant ligament between the pulmonary trunk and aorta
what happens if the ductus arterious fails to close at birth?
can result in an patent ductus arteriosus (PDA), which permits the mixing of high oxygen blood in the aorta and low oxygen blood in the pulmonary trunk
define septa
partition between chambers
name the different septa and where they originate from
- atrioventricular septum (mesoderm)
- atrial septum (mesoderm)
- ventricular septum (mesoderm and neural) - membranous (neural crest) and muscular (mesoderm)
- aorticopulmonary septum (neural crest)
label this diagram with the adult cardiac septa
A = atrial septum
B = av septum
C = ventricular septum
label this diagram with the adult cardiac septa
a = aorticopulmonary septum
b = membranous ventricular septum
c = muscular ventricular septum
label this diagram of the atrioventirulcar septum
A = fusion of endocardial cushions
B = AV canals
C = common artia
D = common ventircle and outflow tract
label this diagram of the atrial septum
a = AV septum
b = secondary atrial septum
c = primary atrial septum
d = foramen ovale
when does the AV septum form?
around 28 days/4 weeks
when do the ventricular septum and aorticopulmonary septum form?
around 5 weeks
what does the aorticopulmonary septum separate?
aorta and pulmonary trunk
when does the atrial septum form?
around 5 weeks
how are CHDs patent foramen ovale and patent ductus arteriosus caused?
when foetal cardiac shunts fail to close at birth
how can neural crest abnormalities cause CHDs?
Neural crest abnormalities can lead to impaired cell migration and adhesion. This can disrupt the development of the cardiac structures to which the CNCCs contribute.
how are VSDs caused?
neural crest defects can cause the membranous ventricular and aorticopulmonary septum to be ‘shifted’ to the right
can cause a VSD, meaning blood from right and left ventricles can mix
what are the 4 features of tetralogy or fallot CHD?
- Pulmonary stenosis
- Over-riding aorta
- Right ventricular hypertrophy
- VSD
what causes Tetraology of Fallot?
cardiac neural crest cell abnormality
what is a patent ductus arteriosus?
when the foetal cardiac shunt between the pulmonary trunk and descending aorta doesn’t close at birth
label this image of the features of Tetralogy of Fallot
A: Pulmonary artery stenosis
B: Pulmonary valve stenosis
C: Over-riding aorta
D: Ventricular septal defect
E: Right ventricular hypertrophy. Growth of the right ventricular myocardium occurs due to the work required to pump blood via both pulmonary trunk and aorta.
F: Patent ductus arteriosus. The ductus arterious is a foetal cardiac shunt between the pulmonary trunk and descending aorta. This channel should close at birth to form the ligamentum arteriosum but remains patent in this abnormality.
