Embryology Flashcards
From what germ layer are the heart and vessels developed from?
Splanchnic mesoderm of lateral plate mesoderm of mesoderm
When does development of the primitive heart tube occur?
Week 3, day 16
When does the primitive heart begin to beat?
Week 4, around day 19-20
What is the sinus venosus?
Inferior portion of primitive heart tube that receives blood from the placenta
What are the parts of the primitive heart tube from inferior to superior?
Sinus venosus
Primitive atrium
Primitive ventricle
Bulbus cordis
Truncus arteriosus
Where does blood from the primitive heart tube go?
Into the aortic arch system
What develops from the truncus arterioris?
Ascending aorta
Pulmonary trunk
What develops from the bulbus cordis?
Conus arteriosus
Aortic vestibule
What develops from the primitive ventricle?
Trabeculated portions of the R and L ventricle
What develops from the primitive atrium?
Trabeculated portions of the R and L atrium
What develops from the sinus venosus?
Left horn becomes coronary sinus
Right horn becomes sinus venarum
What is another name for heart tube folding?
Cardiac looping
About when does cardiac looping end?
Day 28
What is dextrocardia?
Heart lies on the R instead of the L
What occurs during cardiac looping that leads to dextrocardia?
Heart loops to the L instead of to the R
What other condition is associated with dextrocardia?
Situs inversus
What does the atrial septum begin to develop?
Day 30
What neural crest derivative is the beginning of atrial septum development?
Endocardial cushions
Where do the endocardial cushions appear?
AV canal
What does the interatrial septum develop from?
Septum primum and septum secundum
What mechanism closes the foramen ovale?
Pressure in the L atrium presses the septa together and closes the foramen
Which shunting is associated with non-cyanotic defects?
Left to right
What type of shunting is seen with ASD?
Left to right
What occurs with premature closure of the oval foramen?
Massive hypertrophy of R atrium and R ventricle
Underdevelopment of L side of heart
Death shortly after birth
What is the time frame for IV septum development?
Wk 4 to wk 7
What forms the thick muscular component of the IV septum?
Septum from the base of the ventricle
What forms the membranous part of the IV septum?
R conus swelling
L conus swelling
Inferior endocardial AV cushions
What defect is associated with failure of migration of neural crest cells into the endocardial cushions?
Ventral septal defects
What defect is associated with abnormal development of septum primum or septum secondum?
Atrial septal defects
What type of shunting is seen in VSDs?
Left to right
What septal defect is pulmonary HTN related to?
VSD
What develops into the tricuspid and mitral valves?
Atrioventricular endocardial cushion tissue
What develops into the semilunar valves?
3 swellings of subendocardial cushions