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17 Cards in this Set
- Front
- Back
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What is the septum transversum |
The primordial diaphragm |
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How do the vitelline veins transport blood? |
They run cranially from the yolk sac to the heart, paired on either side of the gut, through the septum transversum and entering through the sinus venosus. A venous plexus is formed from the vitelline veins as they pass through the developing liver. They will become incorporated as hepatic sinusoids. |
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What does the right cranial part of the vitelline veins become? |
The caudal vena cava |
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How is the portal vein formed? |
Two anastamoses form between the caudal parts of the left and right vitelline veins. By rotation of the gut and the opening of the vitelline veins |
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Describe umbilical blood flow into the heart |
Paired umbilical veins bring O2 rich blood from the allantois (ie placenta) and into the portal veins, through the septum transversum and into the sinus venosus. |
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How are umbilical veins altered? |
Middle parts of umbilical veins are incorporated into hepatic sinusoids (similar to vitelline veins). The caudal portion of the right umbilical vein atrophies, while the left caudal portion enlarges. This left caudal portion will transport oxygenated blood from the placenta to liver. |
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Describe the shunt formed in the fetal liver |
A venous shunt forms between the left umbilical vein and the cranial part of right vitelline vein. Both of these structures make up the ductus venosus that will flow straight into the caudal vena cava. After birth, ductus venosus becomes capillary beds. |
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Which veins fuse to form the common cardinal veins? |
The paired cranial cardinal veins and the paired caudal cardinal veins fuse to form common cardinal veins and flow into sinus venosus. |
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What do cranial cardinal veins become with development? |
Cranial vena cava, brachiocephalic vein and internal and external jugular veins |
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What do caudal cardinal veins become with development? |
The caudal vena cava (the right vitelline vein also contributes to this), paired subcardinal veins and paired supracardinal veins. |
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Describe signalling that induces lymphatic vessels |
Lymphatic lineage is similar to venous vessel lineage. From angioblasts, a small amount of NOTCH stimuli induces a venous endothelial cell. Prox1 received by VEGFR3 will induce differentiation into a lymphatic endothelial cell. VEGF C,D will further induce cells to form lymphatic sacs. |
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What are the six lymphatic sacs in the embryo? |
Paired jugular sacs lateral to jugular veins single retroperitoneal lymph sacs close to root of mesentery cisterna chyli dorsal to retroperitoneal Paired iliac sacs near the junction of iliac veins |
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What does the thoracic lymphatic duct connect? |
The jugular sacs with the cysterna chyli early in development, each jugular sac connected to cysterna chyli be a single lymphatic vessel. lymphatic vessels anastamose to form thoracic duct By late stage of development all lymphatic sacs are connected by lymphatic vessels |
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How does a lymph node form? |
lymphatic sacs accumulate lymph tissure around the sacs. Mesenchymal cells of mesodermal origin infiltrate the sacs to form lymph channels |
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Compare and contrast lymph nodes in typical mammals and pigs |
Typical mammal: Afferentvessel runs in through the cortex, past the nodules, then to the medulla, then to the hylusand out efferent lymphatic vessel Nodules are in the cortex Porcine: Instead,lymph moves in through hylus, out through the efferent vessel in the cortex Nodules are in the medulla |
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Which lymphatic sacs become lymph nodes? |
All but the cisterna chyli (paired jugular, retroperitoneal, paired iliac) |
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Describe patent ductus arteriosus (PDA) |
Ductus arteriosus remains open postpartum. Causes rising pressure in the aorta, left ventricle and increase in cardiac output to prevent backflow of blood from aorta into left pulmonary artery. Can also cause increased pressure in right ventricle beacue of increased output into the aorta. continuous or machine like murmur over semilunar valves. |
