Atrial, Ventricular, Septal, & Valvular Development

Question 1

Heart Tube Formation

Answer 1

• Occurs in Week 3 (with gastrulation, neuralation, and neural plate formation)
• Angioblastic bands form pair endocardial hearts tubes
• Paired heart tubes fuse to form a single heart tube during lateral folding

Question 2

Bulbous Cordis (BC)

Answer 2

Becomes most of the right ventricle (smooth part) and outflow tracts (aorta, pulmonary trunk)

Question 3

Primitive ventricle (V)

Answer 3

Becomes most of the left ventricle

Question 4

Primitive atrium (A)

Answer 4

Becomes almost all of the left atrium and anterior part of the right atrium

Question 5

Right sinus venosum (RSV)

Answer 5

Forms the posterior right atrium (smooth area), SVC, and IVC

Question 6

Left sinus venosum (LSV)

Answer 6

Forms the coronary sinus, which lives in the AV sulcus and drains the heart

Question 7

Pulmonary veins

Answer 7

Develop from a pulmonary venous tree at the back of the left atrial wall.

As the left atrium grows, part of the tree trunk gets incorporated into the LA. This is why most of the LA wall is smooth.