Cardiac embryology Flashcards
What is the heart formed from
Cardiogenic plate of mesodermal tissue at head end of embryonic disc
What does the cardiovascular system start as
Pulsatile tube
Where do paired vein enter the heart tube from during development
The trunk, liver, yolk sac, placenta
Where do the arterial arches develop and emerge
From the upper end of the embryo
What are the 5 zones of the primitive tube
- Arterial trunk/ truncus arteriosus
- Bulbus cordis
- Ventricle
- Atrium
- Sinus venosus
Describe the layers of the heart and what they develop from
- Endocardial tube= endocardium
- Cardiac jelly= myocard contraction, cell migration- septa and valves
- Thick layer of mesoderm= myocardium
- Thin epicardial layer= epicardium
How does the developing heart fall during growth of the primitive tube
Falls to the right in a d-looping fashion
How is blood supplied to the heart at this stage
Blood flows from vitelline to common cardial veins to sinus venous, then to atria, from atria to common ventrical, then out through arterial trunk
During this, how does the heart take shape
Sinous venous shifts across bottom to cover all of it, Bulbus cordis folds in to be inline with ventricle, Atrium splits to be alongside bulbus cordis and ventricle on both sides and slightly above, Arterial trunk stays at the top
Describe the partitioning of blood flow through cardiac chambers
- Atria
- Atrio-ventricular canal
- Bulboventricular loop
- Arterial trunk
- Separation of the aorta and pulmonary artery
What do the two horns of the sinous venosus become
- Right horn - becomes incorporated into the atrial wall
2. Left horn not incorporated - becomes coronary sinus
What do the atrioventricular cushions form?
They develop on the atrioventricular canal forming the valves and septa in this area to make the heart four chambered
What is the interatrial septum?
wall that separates atria
What is the intra-atrial septum?
Second septum that forms to maintain R to L flow. Forms a second foramen, which occurs before the closure of foramen primum.
Describe the blood flow into the atria during development
- blood enters the atria from caudal vena cava at this stage
- Aimed at septum primum - pushing to left keeping Foramen ovale open - right atrium to left atrium
- Blood then goes to left atrium - left ventricle - aorta - body