Early heart development and folding of the primitive heart tube

Question 1

During the 3rd week of development, the heart if formed from cells that form a horseshoe shaped region called the _______?

Answer 1

Cardiogenic Region

Question 2

By day 19 (3rd week) two endocardial tubes form. These two tubes will fuse to form a single __________?

Answer 2

Primitive Heart Tube

Question 3

At what day does the embryo undergo lateral folding in which the endocardial tubes have fused to form a single heart tube?

Answer 3

Day 21

Question 4

The heart tube grows and develops bulges that are named what ?

Answer 4

• Bulbis Cordis
• Primitive Ventricle
• Primitive Atrium
• Sinus Venosus (R & L Horn)

Question 5

The Bulbis Cordis forms what structures?

Answer 5

• Most of the RV
• Parts of the Outflow tracts of the Aorta
• Pulmonary Trunk

Question 6

The Primitive Ventricle forms what structures?

Answer 6

• Most of the LV

Question 7

The Primitive Atrium forms what structures?

Answer 7

• Anterior parts of the right and left atria

Question 8

The Sinus Venosus which consists of a Right horn and a Left horn forms what structures?

Answer 8

• Superior Vena Cava
• Part of the Right Atrium

Question 9

At what day does the heart begin to beat ?

Answer 9

Day 23

Question 10

At what day does the heart begin to bend and fold?

Answer 10

Day 23

Question 11

The Bulbis Cordis moves

Answer 11

Inferiorly, Anteriorly, and to the Embryo’s right.

Question 12

The Primitive Ventricle moves to the Embryo’s _____?

Answer 12

Left Side

Question 13

The Primitive Atrium and Sinus Venosus Move

Answer 13

Superiorly and Posteriorly. Now the Sinus Venosus is now posterior to the primitive atrium