embryological dev. of CV - Cole Flashcards
primitive vertebrate CV plan begins.. and present by..
begins mid-week 3
present by week 4
as they migrate PHF cells specified to form left and righ t sides of heart and to form
atria
left ventricle
part of right ventricle
secondary heart field (SHF) forms
remainder of right ventricle
outflow tract - conus cordis and truncus arteriosus
the 5HT PITX2 pathway specificies .. and programs..
left side of body
programs heart cells in priamry and SHFs
master gene for left sidedness
PITX2
patterning of cardiac progenitor celsl occurs at the same time as
laterality (left-right sidedness) is established
circuit that supplies and drains the yolk sac ; separate from umbilical artery and vein; called the “nursery for blood vessels”
vitelline vein and artery
features of embryonic circuit
- series of aortic arches connecting to dorsal aortae
- d. aortae subdivides into smaller vessels to supply embryo
- blood drained by anterior and posterior cardinal veins
- common cardinal vein
bulbus cordis consists of
truncus arteriosus
conus cordis
sinus venosus gives rise to
smooth part of right atrium (sinus venarum)
coronary sinus
oblique vein of left atrium
primitive atrium gives rise to
trabeculated part of right and left atria (auricles)
primitive ventricule gives rise to
trabeculated part of right and left ventricles
bulbus cordis gives rise to
conus cordis: smooth part of right ventricle
aortic vestibule: smooth part of left ventricle
truncus arteriosus gives rise to
aorta, pulmonary trunk
blood flow in embryonic dilation
sinus venosus —> primitive atrium –> primitive ventricle –> bulbus cordis —> truncus arteriosus
more anterior structures (ventricles and outflow tract) are specified as such because of
lower RA concentrations
cardiac looping, the correct folding of heart (due to its rapid growth) is controlled by
PITX2 and the laterality pathway
if messed, heart could fold in different direction (could still work just fine)
grow the fastest during cardiac looping
ventricles and outflow tract
dextrocardia caused by - presents as - can be found with - when does it occur embryologically?
- heart bends to left instead of right
- displaced to right with transposition of heart and great vessels
- most common positional abnormality
- can be found with situs inversus
- during gastrulation or later during cardiac looping
large ocmmunication between chambers that occurs when endocardial cushions fail to fuse – called? what does it result in? blood flow? treatment?
atrioventricular communis
results in common AV canal
giant atrial and ventricular septal defect
enlarged pulmonary trunk (less resistance in pulmonary circ. vs. systemic so all blood flows through there)
- Tx - put band on pulmonary artery to tie it off (lungs less congested now), then patch between right and left chambers then divide the one valve into two valves
formation of interventricular septum
2 parts:
muscular portion devleoping in midline on floor of the PV; growing upward towards ECC
- bublar ridges growing downwards to ECC
most VSDs occur in
muscular portion
but close spontaneously!
most commonly, surgically corrected VSD defects
membranous!
opening between L & R ventricles
associated shunting of blood
ventricular septal defects (VSDs)
presenting baby, signs of cyanosis at 1 year check up
right ventricle has hypertrophied; signs of pulmonary congestion and edema
auscultation and US shoe normal valves
diagnosis? disease mechanism?
VSD!
- initial lung inflation, RV pressure decreases
- get left to right shunting (acyanotic)
- causes increased work by RV, hypertrophy and eventual, right-to-left shunting —> cyanosis
- rate depends on size of VSD
vsd 2 facts
25% of congenital heart defects
4 types based on position and severity
which types of VSDs can have more significance for conudciton
central
proximal
basal
valve of foramen ovale is derived from
septum primum
foramen ovale upper boundary and lower boundary
upper: septum secundum (upper limb)
lower: septum primum
foramen ovale once fused is called
fossa ovalis
RA features in terms of fossa ovale
limbus (septum secundum) fossa ovale( floor, septum primum)
LA features in terms of fossa ovale
fossa ovale (floor, septum SECUNDUM) valve of fossa ovale (septum primum)
ASD, stats, types of defects and what they involve
ASD - common, 10-15% of congenital heart defects
ostium (foramen) primum defects - similar to ECC defects
secundum type - involve foramen ovale and septum primum
sinus venosus - usually near opening of SVC
ASD is a characteristic finding in this TBX5 gene mutation
Holt-Oram SYndrome [ H for heart!! ]
- abnormality of upper extremities
- can also have VSD
in the embryo:
nutritional circuits are
(intra) embryonic circuits are..
nutritional: vitelline and umbilical
intra: cardinal veins
connects umbilical vein with IVC
ductus venosus
marks division between embryonic sinus venosus and embryonic primitive atrium (auricles)
crista terminalis
SVC derived from joining
right anterior cardinal and common cardinal v. via brachiocephalic vein anastamosis
embryo starts out getting drained by umbilical vein, vitelline veins and common cardinal but once sinus venosus is finished developing, we are left with these 3 vessels drianing what
SVC - head & neck
IVC - placenta and caudal regions of embryo
coronary sinus - heart itself
partition of this forms the aortic and pulmonary semilunar valves
Truncus Arteriosus!
disease pathology of eisenmenger’s syndrome; whats failed to form/ fuse? how is the blood shunting initially? later? why?
- equal division of truncus, incomplete fusions of bulbar ridges inferiorly –> VSD
- initial L –> R shunt, increased pulmonary blood flow and hypertension
- prolif. in intima and media to narrow lumen
- increased pulmonary resistance causes R to L shunt and cyanosis
tetralogy of fallot
what is IT?
components? how/ why do they develop?
- pulmonary stenosis
- VSD [blood being shunted from right to left ventricle into the aorta]
- overriding aorta
- rt. ventricular hypertrophy [pulmonary trunk too small so ventricle hypertrophies to compensate]
[PS listen to H.O.V. ]
breathing new born exhibits severe cyanosis immediately after birth and dies
- boh ventricles of normal size, no A or V septal defects
- lungs of normal size and well inflated
diagnosis?
transposition of great vessels
adult derivative of umbilical vein
ligamentum teres hepatis
adult derivites of vitelline vein
portion of IVC hepatic veins/ sinusoids ductus venosus portal superior/ inferior mesenteric v. splenic veins
adult derivatives of cardinal veins
SVC internal jugular veins portion of IVC renal and gonadal veins intercostals veins hemiazygous and azygous veins
all types of TAPVR must have this for survival
ASD!
for shunting of blood from right atrium to left
rare congenital malformation in which all four pulm. veins do not connect normally to left atirum
total anomalous pulmonary venus return (TAPVR)
- all four drain into right atrium by abnormal connection
types of TAPVR
surpacardiac TAPVR - pulmonary veins drain into right atrium via SVC
cardiac TAPVR - pulm. veins come together behind heart and drain to right atrium through coronary sinus
infracardiac TAPVR - pulm. v. drain to right atrium via hepatic veins and IVC
Right aortic arch features
- persistence of right 4th arch distal to right subclavian
- left segment caudal to left subclavian disappears
- isolated OR
- may appear with situs inversus/ dextrocardia
double aortic arch features
- segment of right 4th aortic arch caudal to right subclavian
- vascular ring aorund trache and esophagus
- noticable in babies if crying a lot, can’t get oxygen in
coarctation of aorta
- coarc. of aorta distal to left subclavian
typically near ductus arteriosus (postducal is adult, preductal is infantle; depending on if it comes before or after DA) - collateral circulation includes Internal thoracic Artery and its branches (ribs romedel, appear wavy on x ray!)
newborn exhibiting severe cyanotic symptoms in abdomen pelvis and lower limbs but not in head, neck or upper limbs
coarcation of aorta!
blood getting ut into aortic arch; cyanotic only below thorax
heart in abdomen
congenital cardiac exposure syndrome
heart born completely outside of body
ectopia cordis!
can fix it surgically wtf
