Heart embryology and morphogenesis Flashcards
What does the truncus arteriosus give rise to?
Ascending aorta and pulmonary trunk
What does the bulbus cordis give rise to?
Smooth parts (outflow tract) of left and right ventricles
What does the primitive atrium give rise to?
Trabeculated part of left and right atria
What does the primitive ventricle give rise to?
Trabeculated part of left and right ventricles
What does the primitive pulmonary vein give rise to?
Smooth part of left atrium
What does the left horn of the sinus venosus give rise to?
Coronary sinus.
What does the right horn of the sinus venosus give rise to?
Smooth part of right atrium (sinus venarum)
What does the right common cardinal vein and right anterior cardinal vein give rise to?
Super vena cava.
Big picture: what are the steps of cardiac morphogenesis?
- Myocardial specification
- Formation of linear heart tube
- Cardiac looping
- Septation of the chambers
- Outflow tract formation
- Valve development
How early are cells assigned myocardial fate?
As early as first few weeks - heart beats spontaneously by week 4.
What is the cardiac crescent?
Group of cells on the anterior rim that will form the heart tubes.
From what does the linear heart tube initially form?
Two separate tubes that migrate to the midline and fuse
Why is dorsal mesocardium important?
It suspends the developing heart from the rest of the embryo; very important bc all the vessels going in/out of heart must travel in the dorsal mesocardium
Where does the heart beat in the linear heart tube come from?
Intrinsic pacemaker activity of heart tube cells, caudal > cranial
In what direction is blood flow in the linear heart tube?
Caudal to cranial
When does cardiac looping begin?
Week 4 of development
What does cardiac looping establish?
Left to right polarity
What can cause dextrocardia?
Defect in L/R dynein, as seen in Kartagener syndrome (primary ciliary dyskinesia)
Where is the atrioventricular canal and what does it give rise to?
In between atrium and Left ventricle section on looped primary heart tube; gives rise to the mitral and tricuspid valves
What forms the valve of the foramen ovale?
Septum secondum and leftover septum primum
How is a patent foramen ovale caused?
By failure of septum secondum and septum primum to fuse after birth.
What can a patent foramen ovale cause?
Allows venous thromboemboli to enter systemic circulation instead of getting caught in the lungs; can result in stroke or arterial thromboembolism.
What are the three components of closure of the interventricular foramen?
1) proliferation of muscular tissue
2) Aorticopulmonary extension and 3) endocardial cushion extension form membranous portion of interventricular septum
Where are ventricular septal defects commonly found?
In the membranous portion of the septum.
