What layer do arteries veins, and lymphatic channels develop from?
mesoderm all vessels begin as groups of mesodermal cell clusters
What do extraembyronic vessels form from initially?
yolk sac vessels for the placenta
When do embyronic vessels form?
shortly after extraembryonic vessels
What structures do red blood cells form from initially?
1. yolk sac2. liver3. spleen, thymus, and bone marrow
What are the three big arterial networks seen in an embryo?
1.Aortic Arches: associated with pharyngeal arches (4th and 5th weeks)2.Vitelline3.Umbilical
What embryonic structure is the vitelline duct associated with?
yolk sac: blob of endoderm that will form the gut thus vitelline arteries supply the gut
What is the function of umbilical vessels?
connect to mother through placenta for exchange of nutrients
How many arches are initially seen on the aortic arch?
6note: do not pick arch number 5 for anything, dissappears in mammals and doesn't contribute to anything
Label part two of the aortic arches development
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Label part 3 of the developing aortic arches
Note: close to pattern seen in adults, shift in symmetry
What will occur to the different arches of the aorta during part 3 of development?
Dashed lines for 1 and 2: mostly regress and form parts of other vesselsArch 3 on both sides contributes to the carotid systemArch 4 on right forms the right subclavian artery, on the left it forms the arch of the aorta5 disappearsArch 6 will form the pulmonary artery, on the right it loses connection to subclavianOn the left the connection remains between pulmonary artery and ductus arteriosus
What is the ductus arteriosus?
A structure in embryo connecting the pulmonary trunk to the aortaActs as a shunt: prevents blood from going to lungs and instead dumps it back into aorta
What arches of the aorta is the vagus nerve associated with?
4 and 6 (through recurrent nerve) Right at root of the neck under subclavian artery Left: in thorax under the arch of the aorta
What will arch 3 of the aorta become?
contributes to carotid system (common and internal carotid arteries)
What will arches 1 and 2 of the aorta become?
regress and become parts of other vessels (maxillary artery)
What will part 4 of the aorta become?
on right forms the subclavian artery, on left forms the arch of the aorta
What will arch 6 of the aorta become?
pulmonary arteries and ductus ateriosus loses connection to subclavian on right but maintains connection to aorta on left through ductus arteriosus (shunt)
Besides rearrangement of branches 1-6, what other changes are seen in the aortic arch system?
disappearance of the carotid duct (connects the 3rd and 4th arches) the right dorsal aorta disappears between 7th intersegmental and left dorsal aorta elongation of carotid and brachiocephalic arteriesrecurrent laryngeal nerves: supply the 6th arch
Answer the following clinical case
supported by blood flow between aorta and pulmonary trunk: mixing of arterial and venus blood
A 22 year old male presents with the following image and dysphagia. What is the diagnosis?
Double aortic arch: compresses the esophageal airway
Answer the following clinical case
C: right subclavian artery, normally comes off of A
What are the different vitelline arteries and what do they supply?
Foregut: celiac artery Midgut: Superior mesenteric arteryHindgut: inferior mesenteric artery Thoracic: esophagus
Aside from aortic arches what are the other branches from the aorta?
•intercostal•middle suprarenal•renal•"gonadal": testicular or ovarian come off aorta sideways (lateral side)
What is an artery?
A blood vessel that carries blood away from the heart
What is a vein?
a vessel that carries blood to the heart
What vessel in the body will carry the most oxygenated blood?
pulmonary vein
What is the function of umbilical arteries and what will they form in adults?
Take blood from the embryo and send it to the placenta to be oxygenated initially paired branches of the dorsal aorta that supply the allantois during the 4th week of development the vessels shift to the common iliac after birth these vessels loose functional significance and become obliterated and become known as medial umbilical ligaments
What anomalies are associated with development of the arterial system?
1. Patent ductus arteriosus (PDA) 2. Coarctation of the aorta a. Infantile: often symptomatic in early childhood; with tubular hypoplasia of the aortic arch proximal to a PDA b. Adult: narrowing of the aorta opposite a closed ductus arteriosus, but distal to the great vessels arising from the aortic arch On chest radiograph = "figure 3 sign" (see radiopedia.org) 3. Abnormal origin of the right subclavian artery; dysphagia lusoria 4. Double aortic arch
What are the symmetric systems of veins seen in the 5th week of development?
1. Vitelline (omphalomesenteric)2. umbilical 3. cardinal
Where will vitelline veins carry blood from?
yolk sac (GI tract) to the sinus venosus
What will form form blood islands?
vascular endothelium and red blood corpuscles
Where will umbilical veins carry blood?
carry oxygenated blood from the placenta to the embryo (through umbilical cord)
Where will cardinal veins drain blood from?
Cardinal veins: principle veins of the embryo, drains body wall, trunk, limbs, head and neck
What is the sinus venosus?
bottom of the embryonic heart, collects all the venous blood from the embryo (send it to right atrium)
How will the vitelline and umbilical veins shift during development?
Right umbilical vein is smaller and shrinking, will eventually disappearLeft vitelline vessel will disappear and will be left with vitelline vessel only on the right
How is the portal vein formed?
Vitelline veins form a plexus aroun duodenum which will eventually conalesce into the portal vein
What part of the vitelline ceins will contribute to portal system?
left vitelline veins, will loose their direct connections ot the sinus venosus
LIst the veins that will arise from the vitelline veins
i. small region of the IVC (see below) ii. portal vein iii. ductus venosus iv. hepatic v. superior mesenteric vi. inferior mesenteric vii. splenicThink: Small Penises Dont Hurt SIS
What is the ductus venosus?
A shunt at the end of the umbilical cord which allows blood coming from the placenta to bypass the liver and empty directly into the IVCallows nutrient rich blood to reach the brain and face
What will be the most oxygenated blood in an embryo?
blood in umbilical vein (coming straight from placenta)
What will the left umbilical vein remain as in adults?
ligamentum teres hepatis
What iwll the ductus venosum remain as in adults?
ligamentum venosum
What does the ductus venosus allow communication between?
left umbilical vein and right vitelline (hepatocardiac) channel
What are the four main channels initially seen in cardinal veins?
right and left anterior cardinal veins (head, neck, UL>>>trunk) right and left posterior cardinal veins
How are common cardinal veins formed?
formed as the anterior and posterior veins fuse before entering the sinus venosus
How will the cardinal veins shift throughout development?
Anterior cardinal veins eventually shift and only seen on the right, left just has coronary sinus remainAnterior cardinal vein will become superior vena cavaLeads to asymmetric drainage of the gonads: on right drain directly to IVC, on the left drain into renal vein
What are the additional channels formed from cardinal veins during weeks 5-7 of development?
a. subcardinal veins - drain the kidneys b. sacrocardinal veins - drains the lower extremities c. supracardinal veins - drain the body wall
What is shown in the following image?
double SVC
During fetal life, in which of the following structures is the percent hemoglobin/oxygen saturation level of fetal blood the lowest?A.Umbilical veinB.Ductus venosusC.Inferior vena cavaD.Ductus ateriosusE.Left ventricleF.Ascending aorta
Answer: D, shunts blood away from arteries to the umbilical arteries which will then take it to the placenta to be oxygenated
What is the ductus venosus directy continuous with?
umbilical vein
What is the function of the valve of the coronary sinus?
prevent backflow into the coronary sinus
What is the function of the valve of the IVC?
not a backup valve, is a direction valve, bypasses right side of the heart, goes from right atrium to left atrium through the foramen ovale
List the structure in the adult that are direct remnants of the neonatal circulation
Umbilical arteries become umbilical ligamentsUmbilical veins become round ligament of the liverDuctus venosum becomes ligamentum venosumDuctus arteriosum becomes ligamentum arteriosum
Fill in the following charts of fetal structures, shunts, and adult remnants
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What veins drain the embryonic kidney and what will they become?
the posterior cardinal veins play a major role in draining the embryonic kidney, as the embryonic kidney regresses so does the blood supply; the vast majority of the posterior cardinal veins disappear, as a result the supracardinal veins take on the role of draining the body wall and become the azygos system of veins
How is the left common iliac vein formed?
anastamosis between sacrocardinal veins
What structure will the right sacrocardinal vein contribute to?
lower IVC
What vein will contribute to both the arch of the azygos vein and the left superior intercostal vein?
anterior cardinal veins
Where will the gonadal veins drain?
remember that the venous system is initially a bilaterally symmetric system and the gondal veins initially drain to the subcardinal veins; as development ensues and there is a shift to the rightas a result the right gonadal vein drains to the IVC and the left gonadal vein drains to the left renal vein
What is shown in the following?
congenital lymphedema: dilation of lymphatic channels or congenital hypoplasia of lymphatic channels
What is shown in the following?
fetal hydrops
What is shown in the following?
Cystic hygroma - large swellings composed of fluid filled cavities; involve jugular lymph sacs that fail to connect lymphatic vessels
What are anomalies associated with the development of the venous system?
1. double IVC: persistence of left supracardinal vein 2. absence of IVC 3. Perisisten left SVC/ souble SVC
How does the lymphatic system develop? Include lymph sacs that will form
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How is the thoracic duct formed?
initially a paired vessel that has numerous anastomotic channels and later fuses to form the definitive thoracic duct; formed by the inferior portion of the right thoracic duct, the superior part of the left thoracic duct and the connecting channels
Draw fetal circulation and compare to changes after birth
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