Embryo- Heart development Flashcards
during Week 3, the Heart Development Begins Within what?
Cardiogenic Mesoderm
what is the 1st sign of heart development?
formation of a solid, horseshoe-shaped endothelial cord
where does the horseshoe-shaped endothelial cord form?
within the cardiogenic mesoderm
what is another name for the endothelial cells that make up the horseshoe cord?
Angioblastic cord
- made of splanchnic mesenchymal cells
during early development, what cavity is forming just dorsal to endothelial cords?
pericardial cavity
the lateral sides of the horseshoe-shaped endothelial tubes fold in medially & ventrally, forming what?
a single heart tube (endocardial tube)
the ______ ________ holds the heart to the back of the pericardial cavity
Dorsal mesocardium
Prior to head folding, the heart is:
- Rostral to oropharyngeal membrane
- Ventral to pericardial cavity
after head-folding is complete, the heart is:
- Caudal to oropharyngeal membrane
- Dorsal to pericardial cavity
the Dorsal Mesocardium eventually degenerates, forming what?
Transverse Pericardial Sinus
name the layers of the primitive heart tube, from deep to superficial
1) Endothelium
2) Cardiac jelly
3) Myocardium
4) Epicardium
what are the eventual derivatives of the primitive heart tube layers?
Endothelium- endocardium
Cardiac jelly- extracellular matrix
Myocardium- cardiac muscle
Epicardium- Visceral pericardium
all layers of the primitive heart tube are derived from ________ _________
splanchnic mesoderm
the cardiac jelly is produced by the ________, and will eventually degenerate
myocardium
name the 5 primitive chambers of the developing heart tube
A) Truncus arteriosis B) Conus Cordis C) Primordial Ventricle D) Primordial Atrium E) Sinus Venosus
the Bulbus Cordis contains what?
The Truncus Arteriosis and the Conus Cordis
what separates the Conus cords from the primordial ventricle?
Bulboventricular sulcus
the Atrioventricular sulcus separates which 2 structures?
Primordial ventricle & the Primordial Antrum
all blood first enters the ________
sinus venosus
The __________ separates the sinus venosus from the primordial atrium
sinoatrial canal
what structure connects the Primordial ventricle to the Bulbus Cordis?
Primary interventricular foramen
found within the bulboventricular sulcus
As the heart folds, its cranial end will shift:
ventrally, caudally, and to the right
during heart folding, the caudal end will shift:
dorsally & superiorly
trace the flow of blood through the primordial heart:
1) Sinus venosus
2) primordial atrium
3) atrioventricular (AV) canal
4) left ventricle (primordial ventricle)
5) interventricular (IV) foramen
6) right ventricle
7) conus cordis
8) truncus arteriosus
9) aortic sac
10) pharyngeal aa.
11) dorsal aortae
During partitioning of the AV canal, _________ cells near the AV junction revert to mesenchymal state
endothelial
what causes the endocardium to bulge out into the Atrioventricular canal?
proliferation of mesenchymal cells (from the endothelium of the AV junction)
what forms the atrioventricular septum?
Dorsal and ventral endocardial cushions develop and fuse together
what does the atrioventricular septum divide?
divides the atrioventricular canal into right and left AV canals.
Partitioning the primordial atrium involves forming two septa that will fuse together to form the ____________
interatrial septum
which atrial septum is developed first? second?
Septum primum
Septum secundum
the ___________ develops from the roof of the primordial atrium as a thin, moon-shaped membrane
septum primum
what is the foramen primum?
The opening between the inferior edge of the septum & the endocardial cushions
where are the foramen secundum formed?
holes form in center of septum primum through apoptosis
what develops as a result of holes forming/uniting in the septum primum membrane?
foramen secundum
the Septum secundum grows inferiorly and develops an opening, called the ____________
the foramen ovale
Blood entering heart now passes from R to L atrium through which structures?
foramen ovale (in the septum secundum) and foramen secundum (in the septum primum)
Before Birth: Blood Flows From Right to Left Atrium Through what?
the foramen ovale
when does the foramen ovale close off?
at birth
what is the postnatal remnant of the foramen ovale?
The foramen ovale closes off as a depression in the wall of the R atrium - the fossa ovalis
The opening between R + L ventricles is the ______________
Interventricular foramen
Endocardial cushions fuse with each other, forming a twisting ___________ _______
aorticopulmonary septum
what does the Aorticopulmonary septum divide?
divides the outflow tract into:
A) pulmonary trunk (from right ventricle)
B) aorta (from left ventricle)
the Aorticopulmonary septum fuses inferiorly with what?
membranous IV septum
what is the most common congenital heart defect? what is it a result of?
Ventricular Septal Defect (VSD)
Failure of IV septum to completely form
-usually the membranous portion fails to form
what condition is caused by the Aorticopulmonary septum growing in straight instead of spiraling?
Transposition of the Great Vessels
pulmonary trunk on left, aorta on right
what problems are associated with the Tetralogy of Fallot?
remember: INTERnational House Of PancakeS
A) Interventricular septal defect (VSD)
B) Hypertrophy of right ventricle
C) Overriding aorta
D) Pulmonary stenosis
name the pairs of veins draining into the Sinus venosus
- ) Vitelline veins
- ) Umbilical veins
- ) Common cardinal veins
Originally, the sinus venosus opens directly into the central dorsal wall of the _________
primordial atrium
what is the result of the remodeling of the 3 paired veins?
the right horn of the sinus venosus becomes larger than the left.
Sinos venous shift right
what is the adult remnant of the right horn of the sinus venosus?
Sinus venarum
smooth-walled portion of R. atrium
what does the Left Horn of Sinus Venosus eventually form?
Coronary Sinus
primordial pulmonary veins eventually form what adult derivative?
Smooth Portion of Inner Wall of atrium
what is the final derivative of the Aortic sac?
Ascending aorta
the Truncus arteriosus will become what final structure?
Roots + proximal portions of aorta and pulmonary trunk
which structure will give us the Outflow tracts of ventricles?
Conus cordis
the Proximal segment of the bulbus cordis will form the ______
right ventricle
the Left ventricle is formed from the
Primordial ventricle
the primordial atrium will eventually give rise to the:
Left and right auricles + trabeculated portions of atria
Primordial pulmonary vein and its branches will become what structure in a grown human?
Smooth-walled portion of left atrium
T/F: muscular portion of the Interventricular septum grows cranially toward the AV septum to fuse with it
False
the muscular portion grows toward the AV septum, but does not fuse with it
- a membranous portion closes the 2 ventricles
what closes the Interventricular foramen?
membranous portion of the interventricular septum
