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Development of Venous System | Cardinal, Vitelline & Umbilical Veins Explained by Dr. Azam
MB MBBS
Overview
This video explains the embryological development of the venous system, focusing on three primary sets of veins: umbilical, vitelline, and cardinal veins. It details how these embryonic veins transform into the major veins found in adults, including the superior and inferior vena cava, and the portal system. The explanation emphasizes the dynamic nature of embryonic development, where structures regress, anastomose, and persist to form the final vascular architecture. Key concepts like the fate of the umbilical vein after birth, the derivation of the portal vein from vitelline veins, and the complex formation of the inferior vena cava from multiple contributing vessels are elaborated upon with diagrams and step-by-step explanations.
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Chapters
- The development of the venous system involves three main sets of embryonic veins: umbilical, vitelline, and cardinal veins.
- Umbilical veins carry oxygenated blood from the mother to the fetus.
- Vitelline veins collect blood from the yolk sac, which will develop into the gut.
- Cardinal veins (anterior and posterior) collect blood from the body wall of the embryo.
Understanding these three primary venous systems is crucial because they form the foundation for all major adult veins, and their transformations explain the origin of complex vascular structures.
The diagram illustrates the embryo, yolk sac, umbilical cord, and developing heart, showing the initial positions of the umbilical, vitelline, and cardinal veins relative to these structures.
- Before birth, the right umbilical vein regresses completely.
- The left umbilical vein persists and carries oxygenated blood from the mother to the fetus.
- The left horn of the sinus venosus also regresses, forming the coronary sinus.
- The cranial parts of the left umbilical and left vitelline veins degenerate due to the regression of the left horn of the sinus venosus.
- The ductus venosus forms as a temporary channel between the left umbilical vein and the right hepatocardiac channel, allowing blood to bypass the liver and reach the heart.
This transformation explains how the fetus receives oxygenated blood from the mother and how this blood is partially shunted away from the developing liver, a critical adaptation for fetal circulation.
The left umbilical vein carries oxygenated blood, which is then directed through the ductus venosus to the right hepatocardiac channel, bypassing the liver to reach the heart.
- Vitelline veins are primarily responsible for draining blood from the yolk sac, which develops into the gut.
- As the gut develops, the vitelline veins transform to form the portal venous system.
- Anastomoses form between the right and left vitelline veins, with parts degenerating.
- The remaining portions of the vitelline veins, along with specific anastomoses, ultimately form the portal vein, splenic vein, and superior mesenteric vein.
- The sinusoids, central veins, and hepatic veins within the liver also develop from the vitelline venous system.
This section clarifies the origin of the portal vein, which is essential for draining blood from the gastrointestinal tract to the liver, and highlights the vitelline veins' role in forming intrahepatic vasculature.
The portal vein, responsible for carrying nutrient-rich blood from the gut to the liver, is derived from the right vitelline vein and specific anastomoses, while the liver's sinusoids and hepatic veins also originate from this system.
- Cardinal veins (anterior and posterior) drain blood from the embryo's body wall.
- The right anterior cardinal vein and the right common cardinal vein form the superior vena cava.
- An oblique anastomosis forms to shunt blood from the left anterior cardinal vein to the right side.
- The left anterior cardinal vein and the oblique anastomosis contribute to the formation of the left brachiocephalic vein.
- Persistence of the left anterior cardinal vein without the oblique anastomosis can lead to a double superior vena cava.
This explains the development of the main venous return from the upper body to the heart, detailing how the superior vena cava and its tributaries, like the brachiocephalic veins, are formed.
The right anterior cardinal vein forms the majority of the superior vena cava, while the left anterior cardinal vein, via an oblique anastomosis, contributes to the left brachiocephalic vein.
- The inferior vena cava is formed from a complex combination of several embryonic veins, including parts of the posterior cardinal veins, subcardinal veins, and supracardinal veins.
- The right posterior cardinal vein, right supracardinal vein, right subcardinal vein, and the right hepatocardiac channel are key contributors to the inferior vena cava.
- A transverse anastomosis helps shunt blood from the left to the right side, as the inferior vena cava is primarily a right-sided structure.
- The subcardinal veins give rise to the suprarenal veins (from their cranial parts) and gonadal veins (from their caudal parts).
- The left renal vein is longer than the right because it forms from multiple embryonic venous sources, including the left subcardinal vein and an inter-subcardinal anastomosis.
This section unravels the intricate formation of the inferior vena cava, the largest vein in the body, explaining its multiple origins and the derivation of associated veins like the renal, suprarenal, and gonadal veins.
The inferior vena cava is formed from six contributing structures: the right posterior cardinal vein, right supracardinal vein, an anastomosis between supra- and subcardinal veins, the right subcardinal vein, another anastomosis, and the right hepatocardiac channel.
Key takeaways
- The venous system develops from three primary embryonic venous systems: umbilical, vitelline, and cardinal veins.
- Embryonic veins undergo significant regression, anastomosis, and remodeling to form the adult venous vasculature.
- The umbilical vein is crucial for fetal oxygenated blood supply, with its left portion persisting postnatally as the ligamentum teres hepatis.
- The vitelline venous system is the precursor to the entire portal venous system, including the portal vein and intrahepatic vessels.
- The superior vena cava is mainly derived from the right anterior cardinal vein and right common cardinal vein.
- The inferior vena cava has a complex origin, incorporating contributions from multiple embryonic veins on the right side, with shunting mechanisms from the left.
- Understanding the embryological origins explains anatomical variations and clinical conditions like double vena cava or abnormal venous drainage.
Key terms
Umbilical veinVitelline veinCardinal veinSinus venosusCoronary sinusDuctus venosusHepatocardiac channelPortal veinSuperior vena cavaInferior vena cavaSubcardinal veinSupracardinal veinMesenchymal veinLigamentum teres hepatisLigamentum venosum
Test your understanding
- What are the three primary sets of veins present during embryonic development, and what is the main function of each?
- How does the fate of the right and left umbilical veins differ before and after birth?
- Explain the embryological origin of the portal vein and its significance for the liver.
- What embryonic structures contribute to the formation of the superior vena cava, and how is blood shunted from the left side?
- Describe the multiple embryonic sources that contribute to the formation of the inferior vena cava and explain why the left renal vein is longer than the right.