Embryology Flashcards
(24 cards)
What is the name of the remnant of the ductus arteriosus?
Ligamentum arteriosum
What is the name of the remnant of the ductus venosus?
Ligamentum venosum
What is the name of the remnant of the foramen ovale?
Fossa ovalis
What two components make up the interventricular septum?
Membranous and muscular
What two walls make up the interatrial septum?
Septum primum, septum secundum
Which of the two interatrial septae develop first?
Septum primum
What forms the primitve heart tube?
Fused endocardial tubes
From which germ layer does heart tissue arise?
Splanchnic mesoderm
In the direction of blood flow, name the primitive heart tube sections?
Sinus Venosus, Atrium, Ventricle, Bulbus Cordis, Truncus Arteriosus, Aortic Roots
In which direction does blood flow in the primitive heart tube?
Caudal–>cranial
Describe the flow of blood through the primitive heart after looping?
Through common atria, atrioventricular canal, primitive L ventricle, interventricular foramen, primitive R ventricle, bulbus cordis, truncus arteriosus
What forms the right atrium?
Most of the primitive atrium, a little bit of the sinus venosus (when it enlarges and incorporates it)
What forms the left atrium?
Very little bit of prim. atrium, absorbs proximal parts of pulmonary veins.
What happens to the sinus venosus?
Originally they are equal sized, then venous return favours RHS,
What does fetal circulation bypass? And why?
Liver- otherwise all nutrients would be used up here.
Lungs- because they are behind in development so would become damaged due to blood flow.
What does septation achieve?
Formation of interventricular septum, interatrial septum, also septation of ventricular outflow tract to form aorta & pulm. trunk
Then do lots more on stages of different septations
?
How does the foramen ovale close upon birth?
Upon first breath after birth, pressure in L atrium increases to above pressure in R atrium, TF septum primum pushes against septum secundum and fuses.
What ‘holes’ form in the septum primum?
1st- ostium primum, 2nd- ostium secundum.
Describe the direction of growth in ventricular septation
Muscular septum grows upwards towards endocardial cushion. Then membranous portion closes hole.
Describe septation of ventricular outflow tract
Week 5- spiralled ridges form in walls of Truncus Arteriosus, these ridges then fuse by growing towards each other. They form contruncal ridges which splits it into aorta & pulm. trunk
What results if septation of ventricular outflow trunk in truncus arteriosus fails?
Transposition of great vessels.
How many aortic arches do we have in development?
5–> numbered 1, 2, 3, 4, 6 (NO FIVE!!!)
Where is the recurrent laryngeal nerve found?
Hooked around the ductus arteriosus/ligamentum arteriosum
