Embryology Heart Glossary Flashcards
What is the bulbus cordis?
Superior part of the heart tube. Caudal end forms the smooth part of the ventricles and the cranial end forms the truncus arteriosus
Is there an adult remnant of the bulbus cordis?
No
What is the cardiac jelly?
Gelatinous extracellular matrix that helps regulate migration, proliferation and differentiation. Also plays role in development of the valves and septa of the heart. Separates myocardium and heart tube.
Is cardiac jelly present in adults?
No
What is cardiac looping?
Bending of the heart tube positions the heart in the left thoracic region and creates the “typical” heart shape with the atria posterior to the ventricles.
What are the crista terminalis?
Ridge of tissue in the right atrium between the trabeculated part of the right atrium and the smooth-walled part derived from the sinus venosus.
What are the endocardial tubes?
Paired tubes of the embryo formed by angioblasts. Folding of the embryo brings the tubes into closer proximity and they fuse to form the primitive heart tube.
What are endocardial tubes formed by?
Angioblasts
What do endocardial tubes fuse to form? What brings them closer together to fuse?
Craniocaudal folding
Fuse to form the primitive heart tube
What is the endocardium?
Inner endothelial layer of the heart derived from the heart tube
Where is the endocardium derived from?
The heart tube
What is the epicardium?
Outer layer of the heart also known as the visceral layer of the pericardium. It is derived from the visceral mesoderm. Forms the coronary arteries
What is the epicardium derived from?
The visceral mesoderm
What does the epicardium go on to form?
The coronary arteries
What is purpose of the foramen ovale?
Allows blood to flow from the right atrium into the left atrium, bypassing the right ventricle and lungs
What is the remnants of the foramen ovale after birth?
Septum primum and secundum fuse to form the fossa ovalis (depression found on interatrial septum in the right ventricle)
What is the foramen primum?
Gap in the septum primum where blood can pass between the common atria. Becomes obliterated as the foramen secundum forms superiorly on the septum primum
Is the foramen primum present in adults?
No
What is the foramen secundum?
Opening that forms in the upper part of the septum primum by apoptosis as the foramen primum becomes obliterated
What is the myocardium?
Middle contractile layer of the heart derived from the visceral mesoderm overlying the heart tube
What is the primitive atrium?
A dilation of the developing heart tube that forms from the roughened wall of the atrial wall formed by the pectinate muscles
What is the primitive ventricle?
A dilation of the developing heart tube that goes on to form the roughened majority of the ventricle –> trabeculae carnae
What are the endocardial cushsions?
Structures consisting of loose connective tissue covered by endothelium that are responsible for most septation processes occuring in the heart, particularly between the atria and ventricles
What is the conus arteriosus?
A swelling near the cranial end of the developing heart tube. Goes on to form the smooth parts of the ventricle just before the pulmonary trunk and aorta
What are the smooth parts of the ventricle just before the pulmonary trunk called?
The conus arteriosus
What are the smooth parts of the ventricle just before the aorta called?
Aortic vestibule
What is the septum primum?
First septum to grow down from the roof of the common atrium and contributes to the interatrial septum
What is the septum secundum?
Second septum to grown down from the roof of the common atrium towards the atrioventricular endocardial cushions. An oblique opening (foramen ovale) is created between the septum secundum and septum primum that allows the shunting of blood from the right to left atrium during fetal development.
What happens to the opening between the septum secundum and septum primum after birth?
Opening is closed when septum primum is pressed against the septum secundum and the adult pattern of blood flow is established
What is the sinus venosus?
Caudal end of the developing heart tube that largely degenerates by week 5. The right horn goes on to form the smooth part of the right atrial wall (sinus venarum). The left horn forms the oblique vein of the left atrium and coronary sinus.
What is the truncus arteriosus?
Common arterial outflow at the cranial end. It is septated by the conotruncal septum to form the pulmonary trunk and aorta
What is the ductus arteriosus?
A patent vessel in foetal circulation between the pulmonary trunk and aorta. A shunt in fetal circulatory system so blood can bypass the lungs. Closes shortly after birth to form the ligamentum arteriosum.
What is the conotruncal septum?
Formed by conotruncal swellings in the truncus arteriosus. The septum forms in spiral formation. Contains neural crest cells. Separates the common outflow tube to the aorta and the pulmonary trunk
