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35 Cards in this Set
- Front
- Back
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What group of veins drains the body wall, having the intercostals veins as tributaries?
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Supracardinal veins drain the body wall by way of the intercostal veins, taking over the functions of the posterior cardinal veins
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What group of veins gives rise to liver sinusoids?
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Vitelline veins where the liver cord grows into septum transversum
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What fails to develop in double superior vena caba?
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Left brachiocephalic vein
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The ligamentum venosum is the obliterated ___
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Ductus venosus
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Where does the portal vein originate from?
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Anastomotic vitelline vein network around the duodenum
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Which way is blood flowing in the umbilical vein and umbilical arteries?
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Umbilical vein- blood from placenta to fetus
Umbilical artery- from fetus to placenta |
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Does the umbilical vein continue in the adult?
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Ligamentum teres hepatis
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Where do the renal veins originate from?
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Anastomosis between the subcardinal veins forms the left renal vein
Right subcardinal vein becomes main drainage channel and develops into renal segment of inferior vena cava |
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Where does the superior mesenteric vein originate from?
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Right vitelline vein
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Where does mixing of high oxygen blood with low oxygen content blood occur in the fetal blood as it travels from placenta to organs in the fetus?
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Liver, IVC, right atrium, left atrium, and at entrance of ductus arteriosus into descending aorta
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Describe the primitive venous network
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Venous system of embryo consists of a dorsal systemic and double nutritional network by week 4
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Describe the dorsal system network
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Drains body of embryo proper and carries all the intraembryonic blood
Formed by anterior (drain cephalic part) and posterior (drain remainder) cardinal veins which reach the sinus venous through short common cardinal veins |
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Describe the vitelline veins in relation to the double nutritional network
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Carries extraembryonic blood returning from gut or yolk sac derivatives
Contribute to portal system and form anastomotic network around duodenum on way to septum transversum and heart Liver cords grow into septum and break the vitelline veins into hepatic sinusoids Regress when yolk sac disappears |
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Describe cranial to liver bloodflow
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Left horn of sinus venosus disappears, right vitelline vein enlarges (right hepatocardiac channel) and will ultimately form hepatic segment or portion of IVC
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Describe caudal to liver bloodflow
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Network around duodenum forms a single trunk, portal vein
Right vitelline vein will become superior mesenteric vein which drains primary intestinal loop Distal portion of left vitelline disappears |
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Describe the umbilical veins in relation to the double nutritional network
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Enter embryo by way of connecting (allantoic) stalk and course through septum transversum to heart
More lateral than vitelline vessels but fragmented at later time by growin liver and then connected to sinusoids Proximal portion of both with right umibilica vein disappear, so only left remains to carry blood form placenta to liver Direct communication formed between left umbilical vein and right hepatocardiac channel, ductus venosus This bypasses hepatic sinusoids and connects left umbilical to IVC After birth, umbilical veins and ductus venosus are obliterated and form ligamentum teres hepatis and ligamentum venosum, respectively |
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Describe the development of the superior vena cava
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In week 8, an anastamosis (derived from thymic and thyroid veins) develops between the right and left anterior cardinal veins which gives rise to left brachiocephalic vein
Vena cava system is characterized by appearance of anastomoses between left and right so blood is channeled to right side Above anastamosis, anterior cardinal veins become internal jugular veins Subclavian veins forms in limb and eventually enters anterior cardinal vein Left posterior cardinal loses its connection with left common cardinal, part that persists is left superior intercostal vein Left anterior cardinal vein disappears Left common cardinal vein forms coronary sinus SVC is formed by right common cardinal vein and proximal portion of right anterior cardinal |
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What types of malformations of the SVC are there?
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Left SVC
Double SVC |
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Describe development of the inferior vena cava during week 4
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Series of successive venous networks take place in formation of IVC
Kidney system grows considerably and becomes highly vascularized Subcardinal network takes over the draining of this system initially drained by posterior cardinal veins Posterior cardinal system disappears in middle region of embryo Right subcardinal anastamoses will form prerenal segment of IVC Left subcardinal anastamoses persists as left renal vein Left gonadal vein will empty into left renal vein Right caudal portion of subcardinal vein will form right gonadal vein and a renal segment of IVC Right gonadal vein will empty into IVC |
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Describe development of the inferior vena cava during week 6 and 7
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Supplementary dorsal network develops, the supracardinal system
It runs parallel to sympathetic chain and opens into proximal segment of posterior cardinal veins Supracardinal system drains body wall by way of intercostal veins, taking over function from posterior cardinal veins Anastamoses between sacrocardinal veins forms left common iliac vein Right sacrocardinal vein becomes sacrocardinal segment of IVC Renal segment of IVC connects to hepatic segment (from right vitelline vein); IVC consists of hepatic segment, renal segment, and sacrocardinal segment |
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Describe formation of teh azygous system
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Azygous vein formed by 4th to 11th right intercostal emptying into right supracardinal vein and a portion of posterior cardinal vein
Hemiazygous vein is formed by left 4th to 7th intercostal vein entering the left supracardinal vein and then connects to azygous |
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What are some possible malformations of the IVC?
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Double IVC or absent IVC
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What forms the left brachiocephalic vein?
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Connection between the two anterior cardinal veins
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What forms the jugular system?
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Anterior cardinal veins
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What forms the superior vena cava?
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Right common cardinal vein
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What happens to most of the posterior cardinal veins as new veins form?
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They degenerate
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What are the veins that drain the body wall?
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Supracardinals
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What veins drain the kidneys?
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Subcardinals
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What veins drain lower extremities?
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Sacrocardinals
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What forms the hemiazygous and the azygous system?
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Supracardinals
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What forms the renal and gonadal veins?
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Subcardinals
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What forms the iliac veins?
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Sacrocardinals
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What is the shift of bloodflow?
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Flow for arteries tend to shift to left
Flow for veins tend to shift to right |
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Describe blood flow before birth
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1) Blood returns from placenta (80% O2 saturated) by way of umilical vein
2) Some short-circuited via ductus venosus. Some passes through liver via sinusoids. Sphincter in ductus venosus 3) Blood enters IVC and mixes with deoxygenated blood from lower limbs that enters right atrium 4) Blood guided toward foramen ovale, major portion of blood enters left atrium 5) Some remains in right atrium, mixes with blood from SVC and passes to right ventricle 6) Blood in left atrium mixes with small amount of blood returning from lungs, enters left ventricle then to ascending aorta. Heart and brain supplied with well-oxygenated blood 7) Blood from right ventricle passes into pulmonary trunk then most goes through ductus arteriosus 8) Blood travels through descending aorta to placenta by way of two umbilical arteries. O2 saturation in umbilical arteries is 58% |
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What are the changes in blood flow at birth?
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1) Umbilical arteries close functionally a few minutes after birth. Obliteration takes from 2-3 months. Distal parts become medial umbilical ligaments (folds), proximal parts become superior vesical arteries
2) Umbilical vein and ductus venosus close shortly after arteries. Umbilical vein forms ligamentum teres hepatic. Ductus venosum forms ligamentum venosum 3) Ductus arteriosus closes functionally immediately after birth. Obliteration takes from 1-3 months with formation of ligamentum arteriosum 4) Oval foramen closes due to increased pressure in left atrium and a decreased pressure on right side (blood flow from placenta stopped). Functionally closes immediately after birth. Anatomical fusion where septum primum and secundum fuse occurs later around 3 months (sometimes later). Probe patency- no fusion |
