Embryology and Congenital Defects Flashcards
Primary heart field is formed around ___ from ___derm
wk3
mesoderm
Primary heart field undergoes ___ + ___ folding
lateral and cranio-caudal folding
Heart tube regions cranial > caudal
truncus arteriosus bulbus cordis ventricle atrium sinus venosus
truncus arteriosus becomes ___
aorta and pulmonary trunk
bulbus cordis becomes ___
muscular/trabeculated part of RV
outflow of ventricles
ventricle becomes ___
trabeculated/muscular part of L ventricle
atrium becomes ___
trabeculated/muscular part of both atria
sinus venosus becomes ___
R horn = smooth part R atrium and IVC
L horn = coronary sinus
3rd aortic arches become
common carotid
1st part int. carotid
4th aortic arches become
R = subclavian artery L = part of arch of aorta
6th aortic arches become
pulmonary artery and ductus arteriosus
vitelline veins drain the ____
become ____
yolk salk
hepatic sinusoids and veins and hepatic portion of IVC
Part of umbilical vein that bypasses the liver
ductus venosus
Remnant of umbilical vein in adults
ligamentum teres
cardinal veins drain the ___
systemic venous system
2 umbilical arteries branch off of ___
iliac arteries
1 umbilical vein joins to ___ to => IVC
ductus venosus
Function = foetal homeostasis, gas exchange, acid-base balance, nutrient transport, waste transport, hormone productoin, IgG transport, produces PGE2
placenta
maintains patency of ductus venosus during gestation =
produced in ___
PGE2
placenta
R/L heart is of greater pressure in the foetus
R
3 foetal shunts
ductus venosus
foramen ovale
ductus arteriosus
carries nutrients from umbilical vein to IVC bypassing portal circulation
ductus venosus
R->L atrium shunt
foramen ovale
is a link from the pulmonary bifurcation to the descending aorta
ductus arteriosus
Ibruprofen in foetus =
PGE2 inhibited and ductus arteriosus closes
prevents aorta and carotids getting best oxygenated blood
First breath causes the lungs to ___ => increased ___ and pulmonary vessels ___ => ____ pulmonary resistance
inflate ->increased pO2 => decreased pulmonary resistance
systemic vascular resistance increases in a baby when ____
the umbilical cord is clamped - placenta (large, low resistance vascular bed) removed
____ and ____ at birth cause foramen ovale to shut
first breath
AND
cord being clamped
Factors that decrease PDA after birth =
decreased pulm resistance - less flow through
less PGE2 from placenta and more metabolised by lungs
increased O2 => SM of duct constricts
metabolises PGE2 after birth
lungs
Functional closure of PDA occurs after ___
Anatomical closure occurs at ___
becomes ____
hrs-days
7-10 days
ligamentum arteriosus
In preterm PDA remains patent as ___
SM not developed enough
Treatment for PDA =
NSAIDS
surgery - duct ligation
congenital defect that requires PDA eg.
so give ___ to keep patent until deifinitive surgery
interruption of aortic arch
IV PGE2
PPHN (persistent pulmonary hypertension of the newborn) is due to ___ =>
lung resistance not falling after birth => PDA and patent foramen ovale => cyanosis
In PPHN there is a ___ in the pre(Rarm) and post (Lleg) ductal SaO2
big difference
Treatment of PPHN
ventilate
O2 + NO inhaled - vasodilators
ECLS - extra-corporeal life support - bypasses lung
PPHN is commoner in ___ babies due to
sick
sepsis, acidotic, hypoxic ischaemic insult, meconium aspiration syndrome, cold
Congenital diaphragmatic hernia is an example of an anatomical abnormality that can cause ___
PPHN - persistent pulmonary hypertension of the newborn
Congenital heart defects detected within 1-2 days of life usually present with
murmurs
abnormal pulses
cyanosis
Congenital HDs detected in day 3-7 of life usually present with
sudden circulatory collapse, shock, cyanosis, sudden death
Congenital HDs detected 4-6wks after birth usually present with
signs of HF, less feeding, SOB, sweaty
Cyanotic congenital heart defects =
transposition of the great vessels
tetralogy of fallot
tricuspid atresia
pulmonary atresis with intact ventricular septum
total anomalous pulmonary venous connections
Systemic circulation PDA dependant lesions eg.s
hypoplastic LH
critical aortic stenosis
interrupted aortic arch
critical coarctation of the aorta
pulmonary circulation PDA dependant lesions eg.s
pulmonary or tricuspid atresia
If have duct dependant lesion with no PDA then presents:
3-5 days (if undiagnosed) pale tachypnoeic pallor prolonged cap refill poor pulses hepatomegaly crepitations
tetralogy is a(n) a/cyanotic heart defect
cyanotic
ASD is a(n) a/cyanotic heart defect
acyanotic (initially)
VSD is a(n) a/cyanotic heart defect
acyanotic (initially)
Machine gun murmur =
PDA
