Embriologia do sistema cardiovascular: Veias.

Summary

In this lecture on embryology, Professor Verônica discusses the formation of veins in the cardiovascular system, detailing the embryonic development of venous vessels. She explains how veins, including vitelline, umbilical, and cardinal veins, develop from differentiated cells in the splanchnic mesoderm. The process involves various venous structures evolving to form critical components like the hepatic veins, inferior vena cava, and ductus venosus. Professor Verônica also highlights the differentiation of the left and right vitelline veins, the changes in the cardinal veins, and the subsequent formation of essential adult venous structures. She concludes by touching on related anomalies and clinical considerations.

Takeaways

• 😀 The lecture discusses the formation of veins in the cardiovascular system during embryonic development.
• 😀 Venous vessels, like arterial vessels, originate from mesodermal cells called hemangioblasts.
• 😀 The differentiation of venous and arterial vessels depends on different inductors that guide endothelial cell formation.
• 😀 The formation of venous vessels begins around day 17 of embryonic development.
• 😀 Three main groups of veins form the venous system: vitelline veins, umbilical veins, and cardinal veins.
• 😀 Vitelline veins drain the yolk sac and play a role in the development of structures like the liver and the portal vein.
• 😀 Umbilical veins bring oxygen-rich blood from the placenta to the embryo, with the right umbilical vein regressing and the left one continuing to develop.
• 😀 Cardinal veins drain the head, neck, and body regions, eventually forming structures like the jugular veins and the superior vena cava.
• 😀 The venous system undergoes significant changes and regressions after birth, including the formation of ligaments from structures like the umbilical vein and ductus venosus.
• 😀 Anomalies in the venous system, such as failure of regression or improper differentiation, can lead to developmental issues, which will be discussed in future lessons.

Q & A

What is the main topic discussed in this lecture?

The lecture focuses on the formation of veins and venous structures in embryology, specifically the development of the venous system in the cardiovascular system.

What is the origin of venous vessels in the embryonic development?

Venous vessels originate from differentiated cells in the splanchnic mesoderm, particularly the hemangioblasts, which give rise to precursor cells that form the venous vessels.

How is the formation of venous vessels different from arterial vessels?

The formation of venous vessels differs from arterial vessels in that different inducers trigger the differentiation of endothelial cells into venous or arterial structures. Both processes begin at around the 17th day of embryonic development.

What are the main groups of veins formed in the embryonic cardiovascular system?

The main groups of veins are the vitelline veins, umbilical veins, and cardinal veins, which are crucial for forming the venous structures in the embryo.

What happens to the venous structures as they approach the heart?

All veins eventually drain into the caudal portion of the heart tube, known as the sinus venosus, where blood enters the heart before being pumped out through the arterial structures.

What is the role of the vitelline veins in embryonic circulation?

The vitelline veins drain the yolk sac and contribute to the formation of the hepatic sinusoidal capillaries, the superior mesenteric vein, the portal vein, and the inferior vena cava.

What does the left vitelline vein contribute to in the developing embryo?

The left vitelline vein regresses and contributes to the formation of the coronary sinus, whereas the right vitelline vein differentiates into several important structures, including the hepatic sinusoidal capillaries and the portal vein.

What are the key derivatives of the umbilical veins?

The umbilical veins bring oxygenated blood from the placenta to the embryo. The right umbilical vein regresses, while the left continues to bring blood but eventually loses its direct connection with the sinus venosus and connects to the ductus venosus, which leads to the inferior vena cava.

What happens to the cardinal veins during the formation of the venous system?

The cardinal veins are divided into anterior and posterior groups. The anterior cardinal veins contribute to the formation of the jugular veins, while the posterior cardinal veins contribute to the formation of the veins in the thorax, abdomen, and pelvis.

What happens to the ductus venosus after birth?

The ductus venosus, which connects the umbilical vein to the inferior vena cava, closes after birth and forms the ligamentum venosum, a fibrous remnant of the fetal circulatory system.