Embryology

Question 1

Describe the primitive heart tube from cephalic to caudal end

Answer 1

Aortic root vessels,
Aortic roots,
Trucus arteriosus,
Bulbus cordus,
Ventricle,
Atrium,
Sinus venosus.
Suspended in pericardial cavity by membrane.

Question 2

Describe cardiac looping

Answer 2

The continued elongation of the heart tube results in bending as lateral growth is restricted by the pericardial cavity.
Cephalic end bends ventrally, caudally, to the right,
Caudal end bends dorsally, cranially, to the left, results in both inflow and outflow being cranial.
Atrium and ventricle communicate via the atrioventricular canal

Question 3

What is the first division between the primitive atrium and ventricle?

Answer 3

The atrioventricular canal

Question 4

When does the transverse pericardial sinus form?

Answer 4

During cardiac looping (days 23-28)

Question 5

Describe the development of the Right Atrium

Answer 5

Develops from most of the primitive atrium, absorbs the right horn of the sinus venosus (left horn recedes)

Question 6

What does embryonic folding do to the developing heart?

Answer 6

Lateral folding creates the heart tube

Cephalocaudal folding brings the tube into the thoracic region

Question 7

What is the transverse pericardial sinus?

Answer 7

The space between the inflow and outflow vessels of the heart.
Posteriorly to the pulmonary trunk and ascending aorta, anteriorly to the superior vena cava

Question 8

Describe the development of the left atrium

Answer 8

The auricle develops from the primitive atrium.

The rest sprouts the pulmonary vein then grows to absorb the proximal parts and the first four branches

Question 9

When does the oblique pericardial sinus form?

Answer 9

When the left atrium expands and absorbs the pulmonary veins