Cardiac Embryology

Question 1

Which germ-layer contributes to the cardiovascular system?

Answer 1

Mesodermal layer

Question 2

How does folding of the embryo contribute to the development of the cardiovascular system?

Answer 2

Lateral folding - creates the heart tube

Cephalocaudal folding - brings the tube into the thoracic region

Question 3

Parts of the primitive heart tube

Answer 3

Truncus arteriosus
Bulbus cordis
Primitive ventricle
Primitive atrium

Question 4

When does looping occur

Answer 4

Starts around day 23

Ends around day 28

Question 5

Adult derivative of septum primum

Answer 5

Left side of the atrial septum

Question 6

Adult derivative of septum secundum

Answer 6

Right side of the atrial septum

Question 7

What happens to the ductus arteriosus at birth?

Answer 7

Closes at birth

Then known as ligamentum arteriosum

Question 8

What happens to the ductus venosus at birth?

Answer 8

Open at birth
Closes by itself within the first week of most neonates (takes longer in pre-term babies)
Stops functioning within minutes of birth
Then known as the ligamentum venosus

Question 9

What happens to the foramen ovale at birth?

Answer 9

Closes at birth
Pulmonary pressure decreases, when lungs become functional, and the left atrial pressure exceeds that of the right -> forces the septum primum against the septum secundum closing the foramen ovale
Leaves remnant fossa ovalis