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How many aortic arches do you have? What is the numbering?
What is the adult derivative of Aortic Arch #1
R/L maxillary arteries (most of this arch degenerates)
Blood vessels form from where?
TWO PLACES: Splanchnic mesoderm in the yolk sac (form vitelline vessels) and in the embryo
What week does the vasculature system develop?
Cardinal, vitelline and umbilical veins drain into what?
the R/L horns of the sinus venosus
Blood vessel connections btw the placenta and embryo develop when?
By week 4
The cells of the splanchnic mesoderm differentiate into what 2 cells?
- Angioblasts-form endothelial layer
- Hemangioblasts-form primitive blood cells
Your primitive blood vessels once they rearrange and form lumens differentiate by what two processes?
- Vasculogenesis- forms major vessesl by the fusion of seperate cavities
- Angiogenesis-forms remainder of vascular system and smaller vessels + branches
- forms major vessels by the fusion of seperate cavities
forms remainder of vascular system and smaller vessels + branches
Fusion @ what level forms the descending aorta?
of L/R dorsal aorta
Aortic arch arteries connect to what vessel?
L/R Dorsal Aorta
What does your second aortic arch form?
Dorsal end forms h
yoid artery which forms L/R stapedial arteries (associated with the EAR)
- **note the stapedial artery is transiently present in fetal life, and it should degenerate
What happens if you stapedial artery doesn't degenerate?
- stapedial artery is from your 2nd aortic arch--
- called Persistent Stapedial Artery (PSA) if it doesn't degenerate
-forms pulsatile mass in middle ear cavity if it doesn't degenerate
Third aortic arch forms what?
- Right and Left Common Carotid arteries (symetrical)
- each common carotid gives rise to an:
- internal carotid (dual origin)
- external carotid (maybe from 3rd aortic arch)
Fourth aortic arch is symmetrical or asymmetrical?
- Asmmetry exists, the left side forms aortic archRight side forms proximal segment right subclavian arteryDistal portion of the right side
Third aortic arch derivatives are symmetrical or asymmetrical?
Symmetrical! what is happening on the left is happening on the right!
in this case, R/L common carotids form and from each an internal and external carotid artery
Left side of the 4th aortic arch forms what structure?
the aortic arch
Right side of the 4th aortic arch forms what structure?
subclavian artery (proximal segment)
The fifth aortic arch forms what structure?
The sixth aortic arch forms what structure(s)?
- Pulmonary ArchRight side forms right pulmonary artery (grows towards lungs)
- Left side forms ductus arteriosus (ligamentum arteriosum after birth and some left pulmonary artery
Is sixth aortic arch development asymmetrical or symmetrical?
Six AA = Asymmetrical, just like 4th.
Sixth aortic arch forms what structures?
- Development is asymmetrical remember.
- pulmonary arch:
- right side forms right pulmonary arch
- left side forms ductus arteriosus (ligmentum arteriosum after birth) + some of the left pulmonary artery
The left recurrent laryngeal nerve loops under what 6th aortic arch derivative?
the ductus arteriosus, which is known after birth as the ligamentum arteriosum)
Important for you to know this for anatomy + embryo
the Right recurrent laryngeal nerve loops under what 4th aortic arch derivative (what side too)
loops under the 4th Aortic Arch derivative on the right side, subclavian artery
The aorta consists of what parts?
- 1.) Ascending aorta
- 2.) Arch of the aorta
- 3.) Descending aorta: which has thoracic and abdominal parts!!!****
What is coarctation of the aorta (CoA)?
Where is it most commonly found?
- the constriction or narrowing of the aorta (results in limited blood flow
- **most commonly found distal to the left subclavian artery
What is a post ductal coarctation?
a constriction of the aorta below (caudual) the ductus arteriosus
MOST COMMON TYPE of CoA
Ductus Arteriosus is normally closed (not patent)
When a postductal CoA is found with a closed ductus arteriosus the extent of the problem depends on WHAT?
****the severity of the stenosis, and development of collateral circulation.
What is pre ductal coarctation?
- Constriction of the aorta above/before the ductus arteriosus.
- Can occur WITH/WITHOUT patent DA
Preductal CoA with a patent DA allows what to happen?
- Right to left shunt, allows for a continuous blood flow from the pulmonary artery to the aorta(low pressure due to the CoA)
- Bad because not much oxygenated blood is going to the systemic circulation because deoxy blood is passing through the DA (DEATH withing a few months of birth due to poor collateral circulation)
- Results in RV hypertrophy/pulmonary hypertension.
Preductal CoA with a closed DA causes what?
- tiny channel in aorta! (no shunt, DA is closed)
- Diastolic overload as a result
- LV failure from overload of blood in LV
- Not many seen, 88% mortality rate
What is the most common type of coarctation?
- POSTductal CoA
- We will see this in our clinics.
*CoA is distal to the ductus arteriosus
Postductal coarctation reults in what?
- Normall the DA is closed so collateral branches (up left subclavian around down internal thoracic and into posterior intercostal arteries) develop during fetal period via intercostal and thoracic arteries!!!!!****
They live because the collateral circulation works WELL.
Double aortic arch is what?
- failure of the right aorta to regress, so you have a R and a L dorsal aorta (only supposed to have L!
- You can have the two aorta constric the esophagus and trachea and cause problems!
What are the adult derivatives of the Vitelline arteries that form the arteries of the gut?***
- 1) Celiac (T12)
- 2) Superior Mesenteric (L1)
- 3) Inferior Mesenteric (L3)
In the fetus your umbilical arteries carry what?
deoxygenated blood and waste products back to the placenta!
In the 5th week your umbilical arteries lose connection with the dorsal aorta and connect to what?
5th pair of lumbar intersegmental artery branches = which form internal iliac arteries
After birth the proximal portions of the umbilical arteries yield what two structures?
- internal illiac arteries
- superior vesicle arteries (supply the bladder)
KNOW! this is easy!!!
After birth the distal portions of the umbilical arteries yield what structure?
They are obliterated to yield medial umbilical ligaments!!!!
Vitelline Veins drain?
Poorly oxygenated blood from yolk sac
Umbilical Veins return?
oxygenated blood from placenta
Common cardinal veins drain ?
poorly oxygenated venous blood from the body of the embryo
Vitelline veins form what two important veins?
- Portal vein, connects to hepatic sinusoids in the liver
- Right vitelline vein enlarges becomes right hepatocardiac channel or the hepatic portion of the IVC
Right vitelline vein enlarges to form what?
right hepatocardiac channel, the Hepatic portion of the IVC
DON'T FORGET THIS!
What happens to your umbilical veins?
- Right umbilical vein is completely obliterated in 2nd month
- Left umbilical vein persists only vein to carry oxygenated blood from the placenta to the heart.Umbilical vein drains into ductus venosus which forms in the liver--which is a fetal shunt to bypass the liver sinusoids.
After degeneration of the posterior cardinal veins what three veins will form in the 7th week to take over their role?
- supracardinal veins: drain body wall
- subcardinal veins: drain kidneys
- sacrocardinal veins: drain lower limb
Anterior and posterior cardinal veins drain into the left and right horns of the sinus venosus via what vein?
Common cardinal vein = MAIN VENOUS DRAINAGE OF THE BODY OF THE EMBRYO
Supracardinal veins, Subcardinal veins and sacrocardinal veins give rise to what veins?
renal, adrenal, gonadal, azygos, hemiazygos veins, which contribute segments to the IVC
The IVC consists of what three segments?
- Hepatic segment (from hepatocardiac channel) right vitelline vein
- Renal segment derived from right subcardinal vein
- Postrenal (sacrocardinal) segment derived from right sacrocardinal vein
ALL FROM THE RIGHT
Superior vena cava forms from what?
anastomoses between right common cardinal vein and right anterior cardinal vein
What is the function of the left brachocephalic vein?
- to shunt blood from left to right
- forms from an anastomoses btw left and right anterior cardinal veins
What is the most common IVC abnormality?
- Absence of Hepatic Segment of IVC
- assoicated with heart malformations
Double IVC is caused by what?
- left sacrocardinal vein fails to lose its connection with the left subcardinal vein
The subcardinal veins mainly drain
The supracardinal veins drain?
the body wall
The sacrocardinal veins drain the ?
The left IVC typically ends at the _________ which crosses anterior to the aorta in the normal fashion to join the right IVC
left renal vein
What is the most common congential persistent segment?
left superior vena cava
What is the cause of a persistent left SVC?
failure of the left anterior cardinal vain to become obliterated
Obliteration of common cardinal and portion of anterior cardinal on the right takes place!
What does a persistent left SVC result in?
blood from rigth side is drained by the persistent SVC into the right atrium through the coronary sinus!!!!
Double SVC is caused by what?
- persistence of the left anterior cardinal vein and failure of left brachiocephalic vein to form.
- So you get two seperate SVC's entering the right atrium!!!!!!
What three shunts exist in fetal life?
- Ductus arteriosus
- Foramen ovale
- Ductus venosus (allows bypassing of liver by majority of blood)
What closes the shunts after birth?
Both cause circulatiory changes in the newborn, which close the shunts! (high pressure now in LA, closes foramen ovale!)
- Opening of pulmonary circulation
- Cessation of placental blood flow
What is the adult derivative of the foramen ovale?
What is the adult derivative of the ductus arteriosus?
What is the adult derivative of the umbilical arteries?
medial umbilical ligaments
What is the adult derivative of the umbilical vein?
ligamentum teres hepatic
Ductus venosus is obliterated, what is the adult derivative?
What is the adult derivative of the ductus venosus (allows shunting of blood around liver in fetus)?
What is the adult derivative of the intra-abdominal portion of the umbilical vein?
ligamentum teres hepatic