Lecture 13 - Heart Development Flashcards
Where does blood vessel formation begin? When?
extraembryonic splanchnic mesoderm; day 17
What do hemangioblasts form
early embryonic erythrocytes and macrophages
What is the early source of hematopoietic cells in the body
liver
what allows the liver to produce the full range of myeloid and lymphoid cells
cells from the AGM region
where do the AGM cells go after the liver
lymph organs and bone marrow
where are blood cells made starting at day 17
yolk sac mesoderm
when is the liver colonized so that it can make blood cells
23 days and continues to birth
when do the AGM cells go to the liver? where are they from?
begins day 27-40; dorsal aorta
when does bone marrow begin developing cells
10.5 weeks
what leads the newly forming blood vessels where they need to go
tip and sprout cells
where doe the newly forming blood veseels collect
extraembryonic splanchnic mesoderm and between somites (paraxial mesoderm)
what is intussuception
splitting 1 vessel into 2
what are angiomas
abnormal blood vessel and capillary growths that are usually benign
what can angiomas sometimes affect
eyesight
what is normally inhibiting the formation of the angiogenic clusters
neural cord
when does the primary heart field normally form
day 19
what causes the heart tubes to unite
lateral folding
what aligns the heart correctly in left/right? up/down?
lateral folding; cranial/caudal folding
what does the proepicardial organ form? what is it made of
visceral mesocardium; dorsal mesocardium
Right after the heart tubes fold, how is the heart arranged
artia are below the ventricles
what veins go into the sinus horns
umbilical vein - oxygenated blood from placenta
vitelline vein - yolk sac drainage
common cardinal vein - lower body/everything else
when do cardiac twitches occur? rhythmic contractions?
22; 24
what is at the future site of the AV node normally?
R sinus horn
what normally causes outflow anomalies
insufficient cardiac looping
what allows the secondary heart field to develop
lateral folding moves it farther away from neural tube’s inhibitory signals
what cell type modulates heart development
NCC with FGF8
what does the primary heart field form
l/r atrium, l vent
what does the secondary heart field form
RV and outflow trunk
what does the formation of primary and secondary heart fields depend on
retinoic acid
what is reverse cardiac looping called
ventricular inversion (LV is on the right)
what is situs invertus
total body mirroring
what is situs ambiguous
partial body mirroring
what is visceroatrial heterotaxia
heart on right and normal GI
what does the left sinus horn become
coronary sinus
what does the right common cardinal vein become
superior vena cava
what does the right vitelline vein become
inferior vena cava
the smooth portion of the internal RA is called the
sinus venarum
what is the border between the sinus venarum and the RA
crista terminalis
what is the process by which the heart normally enalrges
differential growth
what do the interatrial septum and interventricular septum normally get filled in by
they are primarily muscle but cushion tissue fills in the rest
of what origin is cushion tissue
endocardial
where do the pulmonary trunk and aorta get their cushion tissue
endocardial cells and ectodermal neural crest
what happens when the cushion cells don’t form the barrier
persistent av canal
what pathology would you expect with persistent av canal
pulmonary htn, exercise intolerance, SOB, cardiac congestion, increased risk of endocarditis
what is persistent AV canal often linked to
down syndrome
which septum forms first
septum primum
what time does the septum primum form
33 days
when does the septum secondum form
6th week (40 days)
what does the foramen ovale form in
the septum secondum
where are the holes in the two septa in relation to one another
foramen ovale (septum secondum) is lower
what keeps the foramen ovale closed in adults
higher pressure in the left A
what are the common atrial septum defects
excessive resorption of septum primum
diminished septum secundum
ostium primum defect
what is a lower osteum defect
osteum primum defect
what causes double outlet RV
insufficient shifting of AV septum or cardiac looping
what are the symptoms of double outlet right ventricle
show within days
- cyanosis
- breathlessness
- murmur
- eventually, poor weight gain
what is double outlet RV
pulmonary trunk and aorta both exit RV
what does the truncus arteriosis split into
pulmonary trunk and aorta
how do we ensure that we get complete septation of the outflow tract
- have the conal truncal ridges extend completely
2. downgrowth from the atrioventricular cushion tissues
if NCC don’t migrate what effects does that have on cardiopulmonary system
malformation of the heart and great vessels
craniofacial deformations and cardiac issues are both related to what
NCC
what are the most common heart defects
VSD
what do VSD causes
L-> R shunting
what are the symptoms of VSD
- pulmonary congestion
- RV hypertonicity
- pulmonary htn
what is persistent truncus arteriosus
the pulmonary trunk and aorta don’t split
what causes persistent truncus arteriosus
lack of conal truncal ridges
what is the most common cause of cyanosis at birth
tetralogy of fallot
what is the tetralogy of fallot
pulmonary stenosis
RV hypertrophy
overriding aorta
VSD
what does transposition of great vessels and pulmonary valvular atresia cause
immediate cyanosis
what is tranposition of great vessels
RV gets aorta; LV gets pulmonary trunk
what is pulmonary valvular atresia
lack of formation of the pulmonary semilunar valve out of the RV
what things cause RV hypertrophy
aortic valvular atresia
tetralogy of fallot
hypoplastic left ventricle
what causes aortic valvular stenosis
congenital
pathological - rhematic fever
degenerative (over time)
what cardiac defect affects males more than females
aortic valvular stenosis
what heart defect is associated with the development of aortic aneurysms
bicuspid aortic valves
what is bicuspid aortic valve
the semilunar valve leaving the LV is bicuspid instead of tricuspid; expect symptoms similar to aortic valve stenosis
what heart defect is inheritable
bicuspid aortic valve
what is tricuspid atresia
now way from the RV to the pulmonary trunk
what is hypoplastic left ventricle
LV is underdeveloped Mitral valve is not formed or small Aortic valve is not formed or small Ascending portion of aorta is underdeveloped heart works as a single ventricle unit