Embryology Flashcards
when does vascular sys develop in embryo
3rd week
no longer able to satisfy nutritional requirements by diffusion from mother
day #?: heart tube formed
21 days
day #?: folding of heart in embryo
22 days
day #?: looping of heart tube
23 days
largest category of human birth defects
heart and vascular abnorm
day #?: formation of ventricles
40 days
day #?: hematopoiesis and and vasculogenesis
17 days
sites of hematopoiesis in gestation
(month 1) yolk sac –> liver–>spleen–>bone marrow (birth)
what cells form blood vessels (vasculogenesis)
mesoderm cells –> endothelial cells–>vasculogenic cord forms
what regulates endothelial cell differentiation
transcription factors: Fox/Hox/Sox
steps in blood vessel proliferation (angiogenesis) (4)
1) proliferation of endothelial cells
2) migration
3) sprouting
4) intussusception (splitting)
day #?: extraembryonic blood vessel formation (blood islands)
19 days
what shuts help heart in utero to function as “1 chamber” (2)
inter-atrial and ductus arteriosus
L atria–>R
pulmonary trunk –> aortic arch
lungs not functioning*
in utero: where in circulatory system is circulation resistance high/low (pulmonary vs systemic?)
High: pulmonary system; lungs not functioning*
right side of heart
Low: systemic system; placenta=low pressure
left side of heart
when do shunts in heart close?
at birth
after birth: where in circulatory system is circulation resistance high/low (pulmonary vs systemic?)
after shunts close:
High: left side of heart (to body)
Low: right side of heart (to lungs)
what induces the development of the cardiogenic field
myocardial morphogenesis
transcription factors:
BMP, WNT, NKX
~day 17
what is cardiac jelly
~day 22
mesenchyme cells that make up endocardial tube
The gelatinous noncellular material between the endothelial lining and the myocardial layer of the heart
bulbus cordis becomes
~day 22
bulbed shaped portion of heart
becomes part of R ventricle blood outflow tract
what cells form the epicardium
mesothelial cells on surface of septum transversum
what divides to form the aorta and pulmonary artery
truncus arteriosus
what forms the coronary arteries (endothelial lining and smooth muscle)
~day 22
outer lay of mesothelial cells migrating from surface of septum transversum to form epicardium
name process that aligns 4 chambers of future heart correctly
cardiac looping
~day 23-28
~week4
endocardial cushions forms…
fuses at midline to form atrioventricular canal
separates L/R ventricle
~28-35 days
which vein is oxygenated in early embryo vascular system
umbillical vein
the sinus venosus becomes
the coronary sinus and smooth wall of R atrium and sinus venarum in adult heart
in heart looping, how does the bulbus cordis move?
caudally, ventrally, to the R
in heart looping, how does the primitive ventricle move
to the L
in heart looping, how does the sinus venosus move
dorsally and cranially
what is dextrocardia
abnorm condition in which the heart is pointed toward the right side of the chest.
what separates the common atrium
septum primum and secundum
~day 33
what openings connect newly divided atrium in fetus
foramen ovale and ostium secundum
what separates the ventricle in the heart
expanding interventricular septum and conus swellings
~week 7
ridges spiral and fuse
why is spiral of the conotruncal/ aorticopulmonary septum important inside the truncus arteriosus
shunts blood from R ventricle to lungs, and L ventricle to aorta
ventricular septal defects
Defect: IV septum does not form: in a newborn blood flows from L ventricle to R ventricle
what cells form the conotruncal/ aorticopulmonary septum important inside the truncus arteriosus
neural crest cells
abnormality: transposition of great vessels
If Spiral formation in conotruncal septum fails: blood flows from R ventricle to aorta
No oxygenated blood in circulation and newborn dies
If has atrial/ventricle defect some blood can mix and infant can live
what forms the ductus arteriosus
~8wks
the L 6th aortic arch artery
**ligamentum arteriosum pulls L side of recurrent laryngeal nerve lower than R
what later forms the R pulmonary artery
R 6th aortic arch
which # aortic arch later forms the aortic arch
L 4th aortic arch
which aortic arch later forms the proximal R subclvian artery
R 4th aortic arch
what does the 3rd aortic arch later form
common and internal carotid arteries
what does the embryonic aortic sac become
proximal aortic arch and brachiocephalic trunk
what embryonic structure later forms the adult common carotid artery
3rd aortic arch
what embryonic structure later forms the adult aortic arch
truncus arteriosus, aortic sac, L 4th arch, L dorsal aorta
what embryonic structure later forms the adult pulmonary trunk
truncus arteriosus
what embryonic structure later forms the adult ligamentum arteriosum
L 6th arch
what vessel carries oxygenated blood to the fetal heart
umbilical vein
what does the ductus venosus do in the fetal heart
shunts left umbilical vein blood flow directly to the inferior vena cava. Thus, it allows oxygenated blood from the placenta to bypass the liver.
what does the foramen ovale do in the fetal heart
connect L and R atrium
what does the ductus arteriosus do in the fetal heart
connects the pulmonary artery to the proximal descending aorta. It allows most of the blood from the right ventricle to bypass the fetus’s fluid-filled non-functioning lungs
what causes closure of the ductus arteriosus
rise in oxygen tension
bradykinin release= smooth muscle contraction
decreased prostaglandins from mother
occlusion from backward flow
what adult structure forms from the embryonic ductus arteriosus
ligamentum arteriosum
what adult structure forms from the embryonic ductus venosus
ligamentum venosus
what is the ligamentum arteriosum
small ligament attached to the superior surface of the left pulmonary artery and the proximal descending aorta
fixes the aorta in place
closely related to the left recurrent laryngeal nerve
abnorm: ductus venosus fails to close after birth
intrahepatic portosystemic shunt (PSS)
what adult structure forms from the embryonic umbillical vein
ligamentum teres hepatitis
