Heart Development Flashcards
where is the cardiogenic area during the third week of development?
above the neural plate and oropharyngeal membrane
primary heart field
location and composition
progenitor heart cells have migrated and formed the horseshoe shaped primary heart field located in the SPLANCHNIC LAYER OF LATER PLATE MESODERM
secondary heart field
located caudal to the primary heart field in the splanchnic mesoderm prior to foldind and will give rise to most of the outflow track and the right ventricle
endocardial cells
cardiac progentior cells give rise to these endocardial cells that LINE INTERIOR OF HEART.
what lines the interior of the heart/endocardium?
epithelium! from the cardiac progenitor cells of the lateral plate splanchnic mesoderm
what moves the developing endocardial tubes to the thoracic region?
descent of the heart is progressively initated by the head folding
epicardium made from?
migrating cells derived from the proepicardial organ. they migrate over the entire myocardium, eventually forming the epicardium
proepicardial organ
gives rise to the epicardium of the heart and coronary vessels, cardiac fibroblasts
epicardium derived cells form what?
coronary vascular smooth muscle and cardiac fibroblasts (interstitial cells)
three main things the heart develops from
- splanchnic mesoder - primary and secondary heart fields
- neural crest cells
- proepicardium - epicardium, coronary vessels, and fibroblasts (coronary vascular smooth muscle)
when does body folding occur?
3-4 weeks
beginning of heart development where are the outlfow and inflow tracts?
caudal end is receiving end and cranial is the outflow
- MIXING OF DEOXY AND OXY AT THIS POINT
dorsal mesocardium
in early heart development this attaches the heart tube to the dorsal side of the pericardial cavity
suspends the heart in the paracardial cavity
when does heart begin beating?
day 22 of development
transverse pericardial sinus
from the dorsal mesocardium. as it breaks down it forms this cavity/sinus which LIBERATES the tube for further growth and cardiac looping
where does the cranial (arterial end) attach?
pharyngeal arches
where does the caudal end (atrial/venous portion) attach?
embedded in the septum transversum
5 dialtions of heart through development
- Sinus Venous
- Primitive atrium
- Primitive ventricle
- Bulbus cordis (proximal and distal)
- Truncis arteriousis
Sinus venous
Left/right sinus horns that intitially receives three paired veins
primitive atrium
rise to the L and R atria
primitive ventricle
left ventricle
bulbus cordis (proximal and distal (conus cordis)
Proximal = right ventricle
Distal = smooth wall of outflow track of right ventricle = conus arteriousis and left ventricle = aortic vestibule)
PART OF OUTFLOW TRACT
Truncis arteriousis
proximal ascending aorta, pulmonary trunk
symmetry of heart early in development
bilaterally symmetric
dextral looping
cardiac looping and the heart will become asymmetric
where is rapid growth occuring - initiating the cardiac looping?
PROXIMAL BULBOUS cordis and primitive ventricle
cause of differential growth in cardiac looping?
by the primtive ventricle (left) and the proximal bulbis cortis (right)
displacement of the bulbous cordis
caudally, ventrally, and to the RIGHT
displacement of the primitive ventricle
to the left (left is left)
displacement of the primitive atrium
dorsally and cranially
after folding where is the truncoconal region?
toward the midline
the truncis arteriosis is in midline
blood flow early in development
- sinus venosus
- atrium
- ventricle
- outflow tract
- aortic sac
with mixture of oxygenated and de-oxygenated blood
primitive blood inflow (3 veins)
- Vitelline veins
- Umbilical veins
- common cardinal veins
Vitelline veins
de-oxygenated draining the yolk sac and primordial intestine
umbilical veins
oxygenated blood from the placenta
common cardinal veins
de-oxygenated blood draining the head/neck/limbs of embryo
fate of the vitelline veins
(embryo = yolk sac and gut tube_ Adult = 1. portion of inferior vena cava 2. Splenic vein 3. Portal vein 4. superior mesenteric vein 5. inferior mesenteric vein
fate of umbilical vein
right regresses and the LEFT (‘is left’) which continues to bring in oxygenated blood to the embryo from the placenta
fate of cardinal veins
(was draining major part of embryo - head/neck/ and limbs)
FORMS the following:
1. Superior vena cava
2. brachiocephalic vein
3. portion of the inferior vena cava (other portion from the vitalline)
left horn of sinus venosus becomes?
oblique vein of left atrium and coronary sinus
right horn of sinus venosus becomes?
incorporated into the right strium as the smooth walled portion SINUS VENARUM
entrance/ sinuatrial orifice of sinus venosus becomes?
valve of inferior vena cava and valve of the coronary sinus
crista terminalis
dividing line between the trabeculated wall of the primitive atrium and the smooth wall (from right sinus horn)
when do the aoritic arches arise?
end of 4th week
development of endocardial cushions does what
starts to create septation and walls in the heart
septa will form in the what?
PARTITION THE HEART Atrioventricular canal primitive atrium outflow tract primitive ventricle
Endocardial cushions - where do they form and how?
form in the atrioventricular canal and in the outflow tract as expansions of the ECM (jelly) between the myocardium and endocardium
cushion in the atrioventricalar canal are derived from where?
endocardium
cushion in the ouflow tract are derived from where?
neural crest cells
mesencymal transition in atrioventricular canal
the epithelial cells of the endocardium proliferate into the jelly between the myocardium and endocardium (ECM jelly) and form a fibrous like connective tissue)
where do the endocardial cushions form?
dorsal/inferior and ventral/superior portion of the canal and will meet and fuse to form a right and left canal
they also function as primitive valves propelling the blood forward
what becomes aligned with the formation of the atrioventricular septum?
the left av canal is now lined up with the left atrium and left ventricle (canal will become the tricuspid orifice) and the right av canal is now lined up with the right atria and right ventricle
what forms the atrial septum
two embryonic septa (walls) 1. primary septum/septum primum 2. secondary septum/septum secondum and two foramen 1. primary ostium (ostium primum) 2. secondary ostium (ostium secundum)
‘hole in the heart’
from open foremen ovale
foremen ovale and how is it formed
direct pathway of blood from the right and left atrium/ so bypasses the right and left ventricle because receieving oxygenated blood from the mother
FORMED BY INCOMPLETE CLOSURE OF THE SECONDARY SEPTUM SECUNDUM
KNOWN AS THE FETAL SHUNT
position of the foreman ovale
beginning of development this is between the caudal edge of the septum primum and the endocardial cushions (aka the interatrial foramen primum)
septum primum
grow on dorsal part of the atrial chamber and growing towards the atrioventriucla endocardial cushion
foramen secundum
forms by the coalescence of small ruptures in the septum primum
how does the foraemen ovale end up closing?
after birth a fall in pressure will result in the valve of the foramen ovale (from the primary septum) pressing up against the secondary septum
conotruncal septation
BY NEURAL CREST CELLS
the initial single chambered outflow tract is partitioned into separate aortic and pulmonary channels by conotruncal ridges
neural crest cells in heart
migrate from the hindbrain through the pharyngeal arches to reach the heart and contribute to the outflow tract and partitioning of the aortic and pulmonary trunk
what becomes aligned in spiral septation?
aligns the pulmonary trunk with the right ventricle and the aorta with the left ventricle
truncal coushin forms…
DIVIDES the outflow tract into aorta and pulmonary trunk
conal coushin forms…
SEPTATES the outflow tract into left and right ventricular outlets
conotruncal junction…
where the aortic valves and pulmonic valves develop
development of the conotruncal septum
separates the aortic and pulmonary outflow tracts
intraventtricular foramen
apical aspects of the right and left ventricles expand and walls grow closer to eachother and protrude into the lumen and towards the endocardial cushions. They do not fuse at the cushion and the opening is the intraventricular foramen
tissues involved in the mebraneous part of ventriucular system
- right and left conus cordis swellings
- endocardial cushion
- neural crest cells
intraventricular septum
muscularis and membraneous
muscularis septum fuses with what in the interventricular septum development?
fuses with conotruncal septum and endocardial cushion - the ventricular side of the AV septum
complete fusion of the interventricular septum occurs with what
formation of the membraneous part
ductus venosus
a shunt in fetal circulation that allows oxygenated blood from the placenta(mother) to bypass liver and go directly to the inferior vena cava
fetal blood flow
- umbilical vein
- ductus venosus (shunt to inferior vena cava/bypass liver)
- right atrium and through Oval foramen to
- left atrium
- ascending aorta - head and neck regions
ductus arteriosis
blood that has entered right atrium and pulmonary trunk is shunted by this to the descending aorta
umbilical arteries
how blood flow goes back to the placenta
umbilical arteries become
medial umbilical ligaments and superior vesical arteries
umbilical vein becomes
ligamentum teres
ductus venosus becomes
ligamentum venosum
ductus arteriousis becomes
ligamentum arteriosum - connecting trunk to aorta
foremen ovale
fossa ovalis
- complete fusion of the primary and secondary septum usually occurs around 3 months after birth
