Embryology Flashcards
forms the primordium of the heart (muscular wall), conduction system, inflow tract
LP splanchnic mesoderm
earliest sign of development of the heart
paired angioblastic cords (paired endothelial strands)
these fuse to form a single tube that folds back on itself (beginning around day 23) to become the 4 chambers of the heart
when heart begins to beat
day 22-23
forms the fibrous cardiac skeleton, valves, cardiac cushions, atrial & membranous ventricular septa, outflow tract (bulbus cordis and truncus arteriosus) chordae tendinae
neural crest
what forms the hepatic portal system
right vitelline vein
note: the left vitelline vein regresses
Where does the umbilical vein deliver oxygenated blood from the placenta early in development?
sinus venosus
umbilical veins lose their connection with the heart as the embryo develops and empty into the liver
Which umbilical vein disappears during the 7th week of gestation?
right
left umbilical vein remains to carry oxygenated blood from placenta
What connects the umbilical vein to the inferior vena cava?
ductus venosus
this helps most of the oxygenated blood to bypass the liver and pass directly to the heart
most common anomaly of IVC in the adult?
IVC is interrupted in its course and blood drains from the lower limbs, abdomen and pelvis to the heart through the azygos veins
right to left shunt caused by persistence of left anterior cardinal vein
persistent left SVC
the SVC is normall formed by the right anterior cardinal vein and right common cardinal vein
degeneration of the right anterior cardinal vein and right common cardinal vein, leaving blood to enter the SVC and then the coronary sinus via the left brachiocephalic vein
left superior vena cava
inferior part of left supracardinal vein persists
double inferior vena cava
become the internal iliac arteries and superior vesicle arteries (to urinary bladder)
proximal parts of the umbilical arteries
becomes the endocardium
endothelial tube
forms the epicardium
mesothelial cells that arise from the external surface of the sinus venosus
forms the aortic arches
LP splanchnic mesoderm
What composes the truncus arteriosus and bulbis cordis?
neural crest
becomes the foramen ovale
septum secundum
What makes the valve of the foramen ovale?
septum primum
anatomical closure of the foramen ovale occurs when?
around 1 year
Physiological closure occurs after birth when pressures rise on the left side of the heart
most common ASD
probe patent foramen ovale
causes right ventricular hypertrophy
ostium secundum defect
forms from the bulbus cordis
conus arteriosus (right ventricle) and aortic vestibule (left ventricle)
caused by the spiraling failing to occur
transposition of the great arteries
death within a few days or months without surgical intervention
How does IV septum form?
fusing of left and right bulbar ridges with the endocardial cushion
splanchnic mesoderm problem
low VSD
neural crest problem
high VSD, ASD
neural crest and splanchnic mesoderm problem
common ventricle
forms the adult renal veins
subcardinal-supracardinal anastomosis
becomes the coronary sinus
left horn of the sinus venosus
contain the pectinate muscles
the auricles of the atria
carotid arteries form from which aortic/pharyngeal arch
3rd
arch of aorta, R brachiocephalic artery & proximal subclavian form from which aortic/pharyngeal arch
4th
which aortic/pharyngeal arch degenerates?
5th
which aortic arch/pharyngeal arch becomes the pulmonary arteries and ligamentum arteriosum
6th
3rd and 4th pharyngeal pouches fail to differentiate into the thymus and parathyroid glands, leading to facial abnormalities and susceptibility to infection. deletion on chromosome 22q11
DiGeorge Syndrome
embryonic heart tube bends toward the left instead of the right, displacing the heart to the right and reversing the heart and its vessels to a mirror image or the normal configuration
heart function is normal
dextrocardia
if transposition of the abdominal viscera accompanies it: dextrocardia with situs inversus
heart is partially or completely exposed on the surface of the thorax
associated with cleft sternum and open pericardial sac
death within a few days of birth
ectopic cordis
