Embryological Heart and Clinical Correlates Flashcards
Precursor of Aorticopulmonary Septum
truncal and bulbar ridges of neural crest cells through pharyngeal arches (ectoderm)
Function of aorticopulmonary septum
partition of bulbis cords and trunks arteriosis via spiral growth
Failure of aorticopulmonary septum to develop correctly
one outflow path from fused ventricles, or transportation of great arteries (straight line development)
Transportation of Great Arteries
right ventricle to aorta with deoxygenated blood; left ventricle to pulmonary trunk with oxygenated blood. defect in aorticopulmonary septum
Transportation of Great Arteries incompatible with life unless:
patent ductus arteriosus or foramen ovale or a VSD exists so that oxygenated blood in pulmonary trunk (if ductus arterosus present) can go to aorta and systemic system. foramen ovale or VSD would allow mixture of deoxygenated and oxygenated blood in atrium or ventricles, respectively, to provide some oxygenated blood to systemic system.
most common VSD
membranous VSD
Cause of membranous VSD
failure of bulbous ridges to fuse with endocardial cushions and close the intraventricular foramen.
Clinical results of membranous VSD
initially a left to right shunt, causing pulmonary hypertension leading to pulmonary stenosis which reverses shunt and leaders to cyanosis to CHF and Eisenmenger’s Syndrom
Failure of correct migration of neural crest cells from neural tube (ectoderm)
Tetralogy of Fallout, smaller pulmonary trunk (think secondary formed, so smaller) and overriding aorta, Transposition of Great Vessels
4 Effects of Tetralogy of Fallout
1) overriding aorta
2) pulmonary stenosis which results in
3) right ventricle hypertrophy
4) VSD due to superior malalignment of sub pulmonary infundibulum
Parts of the Primitive Heart
blood flows from sinus venous (sinus vernarum and coronary sinus) to primitive atrium (auricles of right and left atria) to primitive ventricle (left ventricle) to bulbis cordis (right ventricle) to conus cordis (conus arteriousus and aortic vestibule) to truncus arteriosus (ascending aorta and pulmonary trunk) to aortic arch
Conus cordis
upper bulbis cords that splits into conus arteriousus (for right ventricle to pulmonary trunk) and aortic vestibule (for left ventricle to aorta)
ASDs
sinus venosis, probe patencey foramen ovale/ AV canal, foramen secundum, common atrium
Probe Patency of foramen ovale/AV Canal
not clinically relevent– failure to fuse septum premium and second, maintaining foramen ovalis,
Foramen secundum ASD
excessive reabsorption, most common, clinically significant
Common Atrium
complete failure for foramen secondum or primum to develop
Ectopia Cordis
faulty development of stream and pericardium due to incomplete fusion of lateral folds, cardiac failure, hypoxema. incompatible with life
Right Sinus venosus splits into
sinus venarum (smooth part of right atrial wall… incorporated in primitive atrium) and coronary sinus
Sinus venarum
pushes pectinate muscles into right half ventral part of primitive atrium, resulting in right auricle and becomes incorporated in wall of atrium.
Original right side of primitive atrium
right auricle
Left atrial wall (grows out, grows in)
incorporation of primitive pulmonary veins (split of the original pulmonary vein) gives it a smooth appearance
left auricle
pectinate muscles displaced by the incorporation of primitive pulmonary veins into left atrial wall.
Pressure switches in primitive atrium and septum closure
Initially, right atrium high pressure keeping flimsy septum primum away from rigid septum secundum due to umbilical vein supply being larger than the pulmonary supply (not needed for fetal lungs). first breath, lungs need oxygenated blood, pressure switch (left more than right) sealing the septum primum to septum secundum becoming the fossa ovalis
Bending of heart tube results in:
shifting of sinus venous into right and left horns to empty in to the right atrium via coronary sinus or septum vernarum (superior vena cava)
Only source of oxygenated blood into the sinus venosus
Umbilical veins from mother
3 ways blood enters sinus venosus
common cardinal veins (anterior/cranial; posterior/caudal) umbilical veins (oxygenated) vitelline veins (deoxygenated) all come into the heart caudally via sinus venosus
caudal and rostral anchor of the primitive heart
caudal-sinus venosus, central tendon of diaphragm
rostral–neck walls
endocardial cushions
divide AV canal into right and left atrioventricular openings
fusion of endocardial cushions
AV septum, preventing mixture of oxygenated and deoxygenated blood
endocardial cushions participate in the formation of
membranous portion of IV septum, closure of foramen primum (helps complete both IV and AV septum)
muscular part of IV septum
muscular upgrowth from primitive ventricle
membranous portion of IV septum
endocardial tissues/endocardial cushions and bulbar ridges (so bulbus is more caudal than truncus)
Primary Intraembryonic Arteries
Paired dorsal aortae
Intersegmental arteries between somites
Aortic arch arteries
Primary Embryonic Veins
cardinal system of veins, and this mixes with umbilical vein
Placenta Bloodflow to Embryo
Umbilical vein
Yolk Sac blood blow
Vitelline veins
What is important about the vitelline vein?
first source of blood cells in the embryonic circulation
what vessel brings embyronic blood back to the heart
cardinal veins
Where/what happens to the dorsal aorta
Caudally fuse together to form descending aorta
what occurs at the rostral end of the embryo in vessel development
truncus arteriousus is continuous cranially with aortic sac, which is produce the pharyngeal arch arteries. aortic arches connect aortic sac to the dorsal aortae
what is the purpose of the caudal umbilical arteries during vessel development?
the develop in the connecting stalk to link the dorsal aortae to the capillaries in the chorionic villi
role of the vitilline arteries in the vessel formation
connected to the dorsal aortae, make a capillary connection to the yolk sack, and become the digestive system arteries (celiac, superior mesenteric, inferior mesenteric)
what are the digestive system arteries from cranial to caudal
celiac, superior, and inferior mesenteric
connects to the dorsal aortae by aortic arches
aortic sac
dorsal aortae to chorionic vessels
umbilical arteries
6 pharyngeal arches suppled by arteries called
aortic arch
aortic arches arise from _____, and this gives rise to
aortic arches arise from aortic sac, which gives rise to the brachiocephalic artery, and the right side of the aortic arch
what happens to first and second aortic arches
regress
what happens to third aortic arch
common carotid arteries, and proximal internal carotid
what happens to fifth aortic arch
there is not a fifth aortic arch
internal carotid is formed by
third aortic arch (proximal) and remainder of upper end of dorsal aorta (distal)
external carotids
sprout from internal carotids
lose dorsal aorta
between 3 and 4 arches on both sides, but also distal to the 7th intersegmental artery (forms the subclavian)
what does the 7th intersegmental artery form
subclavian
dorsal aorta persists on right side and left side to form
dorsal aorta persists on right side to form the medial portion of right subclavian (distal portion is 7th intersegmental arch), persists on left to from the descending thoracic aorta, which the left 7th intersegmental arch branches from to form the left subclavian artery
4th aortic arch
left side is the aortic arch
right side is the proximal subclavian artery
6th aortic arch
right side is the right pulmonary artery
left side is the left pulmonary artery and the ductus arteriousus
proximal part of internal coratid artery
3rd aortic arch
a portion of the aortic arch is dervived from
4th aortic arch
position of recurrent laryngeal nerves in accordance to development
on right side, distal part 6th aortic arch regresses, so the RLN stays with subclavian
left side, distal part of 6th aortic arch remains as ductus arteriousus, so it is brought down with aorta
rib notching
caused by postductal/distal coarctation of aorta which promotes development of extensive collateral circulation to get blood to descending aorta
subcardinal veins
from posterior cardinal veins and drain mesoneophric kidneys, join at mid line to form a venous H
4 components of diaphragm
pleuroperitoneal membranes, central tendon of diaphragm (septum transversum), myoblasts from lateral body walls (skeletal muscle), and dorsal mesentary of diaphragm (crura)
precursor to gonadal veins
caudal subcardinal after the formation of the RCI/LCI
hepatic segment
right subcardinal joint the vitelline duct
renal segment of IVC
distal subcardinal, before hepatic segment
left renal vein
anastomosis of the subcardinal veins
RCI/LCI
right sacrocardinal for RCI
anastomosis of sacrocardinal for LCI
precursor to left bracheocephalic vein
anterior cardinal veins
function of the left bracheocephalic in embryo
shunt blood from left to right anterior cardinal vein
what forms the superior vena cava
right anterior cardinal vein and right common cardinal vein
precursors to azygous vein, hemiazygous vein, accessory hemiazygous vein
AZ-right supracardinal vein
HZ-caudal left supracardinal vein
AHZ- cranial left supracardinal vein
portal vein
anastomosis of vitelline veins around the duodenum
definitive umbilical vein
the dominate, left umbilical vein, returns all of the blood from the placenta
ductus venosus
an anastomosis via hepatic sinusoids between umbilical vein and proximal right vitelline vein
