L2: Development of the heart & its anomalies

Question 1

What is the time of the development of the Primitive heart?

Answer 1

At the beginning of 4th week

Question 2

What is the origin of the primitive Heart?

Answer 2

The cardiogenic plate of mesoderm (Angioblastic cells )

Question 3

What are the steps of the development of the primitive heart?

Answer 3

• Cells in the cardiogenic area collect into two-heart tubes (one on each side).
• Then the two heart tubes will fuse together to give a single heart tube with 2 ends
• one end is venous that receives blood and the other is arterial ejecting the blood.
• Constrictions appear in the heart tube dividing it to 5 segments
• Growth of the heart tube, resulting in its bending into an S-shape.

“After U-shaped, Due to attachment with the esophagus with elongation”

Question 4

What are the segments of the Primitive heart from causal to cranial?

Answer 4

1. Sinus venosus “receive venous blood”
2. Primitive atrium.
3. Primitive ventricle.
4. Bulbus cordis.
5. Truncus arteriosus.

Question 5

What does the S-shaped heart consist of?

Answer 5

1. The right limb: which is formed by truncus arteriosus and bulbus cordis.
2. The transverse limb: which is formed by the primitive ventricle.
3. The left limb: which is formed by the primitive atrium and sinus venosus.

Question 6

When does the heart first beat?

Answer 6

starts at early 4th week (22 days).

Question 7

When are heartbeats first heard?

Answer 7

1st detected heartbeat by ultrasound can be done as early as 6th week.