Development Of The Great Vessels Flashcards
Intraembryonic Vasculogenesis happens what day
Day 19
How does the fetal circulation bypass the liver
The O2 rich blood bypasses the liver and flows into the IVC and RA
MOST OF IVC —> LA (through the foramen ovale)
MOST OF SVC —> RV
*ductus venosum
Where do most fetal blood go after RV
90% goes into descending aorta through the Ductus Arteriosus
10% thought the pulmonary a to lungs
LV pumps blood into
Ascending aorta
What keeps the ductus arteriosus open
Prostaglandins
What causes the ductus arteriosus to close
The O2 tension and BF changes + prostaglandins decrease = cause SM contractions in the patents arteriosus
What can you get if you have an unclosed patent ductus arteriosus
And increased risk for what
Pulmonary congestion and congestive heart failure from LV hypertrophy
Increased risk for maternal rubella infection
To for PDA
Idomethacin or surgery
Coarctation
When the descending aorta thickens in wall and gets constricted and Ductus arteriosus remains open(this can happen before the DA or after the DA attaches)
*more common in Turner’s syndrome
Interrupted aortic arch is most common in what
DiGeorges Syndrome
How many aortic arches are there
6
5th one never truly forms
Which aortic arches hypertrophy
3,4,6
Which vessels are added to the aortic arches
External carotid, distal part of pulmonary artery
Initial growth of dorsal aorta is how
Paired which fused and grows caudally from T4
How is the aorta and pulmonary a formed
The truncus arteriosus is divided by the aorticopulmonary septum
Intersegmental arteries
And how many are there
From parasail mesoderm and they connect to the dorsal aorta
There are 7 C, 12 T, 5 L
Cervical Dorsal Intersegmental Arteries
7
All connected by longitudinal anastomoses
1-6 drop out from anastomoses and become VERTEBRAL As
7th remains on left and becomes LEFT SUBCLAVIAN A and a portion on the RIGHT subclavian A on the right
Thoracic Dorsal Intersegmental Arteries
12
Anastomoses between the inferior and superior IA become INTERNAL THORACIC As
The IA themselves become INTERCOSTAL As
Lumbar Dorsal Intersegmental Arteries
5
These anastomoses become EPIGASTRIC VESSELS + ILIAC VESSELS
What happens to the Aortic Arch of 1
Breaks up and reorganizes with AA 2
Becomes MAXILLARY A
What happens to the Aortic Arch of 2
Breaks up and reorganizes with AA1
Becomes STAPEDIAL As
What happens to the Aortic Arch of 3
Also called carotid arch *main feeder to head
Becomes the COMMON CAROTID + PROXIMAL part of INTERNAL CAROTID
Where does the internal carotid come from
The dorsal aorta
Where does the external carotid come from
The from the AA3
What happens to the Aortic Arch of 4
Left side
Hypertrophied
LEFT : AORTIC ARCH in newborns.
1st part = aortic sac
2nd part = AA 4
3rd part = left dorsal aorta proximal to 7th intersegmental A
4th part = left dorsal aorta distal to 7th IA
5th part = spiral septum connects left AA 4 to the LV
*7th IA becomes the left subclavian a
What happens to the Aortic Arch of 4
RIGTH side
Hypertrophied
Becomes the PROXIMAL part RIGTH SUBCLAVIAN A
*right 7th IA makes the distal part
*dorsal aorta makes middle part
What makes up the proximal right subclavian
The AA 4 right side
What makes up the right subclavian distal part
The right 7th IA
What happens to the Aortic Arch of 5
Never forms
What happens to the Aortic Arch of 6
Becomes the PULMONARY As at proximal part of AA6 and aortic sac
AA 6 on the left side
DA is connected and the recurrent laryngeal N is hooked around distal AA6 = becoming the future LIGAMENTUM ARTERIOSUM
AA 6 of the RIGTH side
Distal part of AA 6 (right) loosed connection with right dorsal aorta as it regresses in the fetus
= causes recurrent laryngeal N (PA 6 nerve) to hook around the future RIGTH SUBCLAVIAN A
Dorsal Aorta has 3 parts
- Between AA 3 and AA 4 : CAROTID DUCT —> obliterated
- Between RIGTH 7th IA and Left dorsal aorta junction —> RIGTH dorsal aorta obliterated
- Caudal part of right and left Dortal Aorta : FUSE ——> Descending thoracic and abd aorta*
Vitelline arteries
Vessels to YOLK SAC which become GI VASCULATURE
Umbilical arteries
Paired from dorsal aorta
To PLACENTA + bladder
Connects to 5th IA lumbar
(Distal parts go to umbilicus are obliterated at birth)
Distal Umbilical arteries
Obliterated and become MEDIAL UMBILICAL LIGAMENTS
Proximal part of 5th lumber IA
Still stay in adult as umbilical arteries with SUPERIOR VESICULAR A branch ——> bladder
In the fetus most O2 rich blood goes where
From the Ascending Aorta to the Heart, Head, Neck, and upper extremities
Reason LV hypertrophies in PDA
The Pressure in the aorta is higher then the pulmonary a
To blood flows from the aorta to the pulmonary a recirculating the lungs (2-3 times) = more work for the LV to pump blood to the body
Endothelin
GF released from lung endothelial cells in fetus = stimulate SM contractions to close the DA
Reason for pulmonary congestion and congestive heart failure in PDA
Increased BF to the lungs = increased pulmonary resistance to limit amount going through lungs
——> pulmonary congestion and eventually backs up into the heart causing congestive heart failure (blowing type murmur)
preductal vs postductal coarctation
POST: sometimes unnoticed due to well developed IA and intercostal As inde interval thoracic As collateral system
PRE : child dies unless surgery, not well developed collaterals, O2 blood doesn’t reach body
Aberrant origin of right subclavian
RIGTH subclavian is made by : DISTAL right dorsal aorta + 7th IA
Right AA 4 and PROXIMAL right dorsal aorta obliterated
*difficulty swallowing + breathing (rda must cross esophagus to reach upper right limb)
Double aortic Arch
Goes around the esophagus and trachea
Can cause esophageal dysfunction or strangulation of trachea
Right Aortic Arch dysfunction
Left AA 4 and Left dorsal aorta are obliterated
Cause dysphagia, dyspnea (left subclavian goes behind and ligamentum arteriosum goes in front of trachea——> left side)
Interrupted Aortic Arch
Right AA 4 + proximal rda obliterated (like in aberrant right subclavian)
AND LEFT AA 4 obliterated also
Ductus Arteriosus remain open (lowO2 to body)
* more likely in DiGeaorges Syndorme
3 Venous systems in the fetus
- VITELLINE : blood from yolk sac —> sinus venosus —> septum transversum
- UMBILLICAL : from chorionic villli in placenta (O2 blood)
- CRDINAL : drains embryo body
Where do the vitelline veins go
Through the sinus venosum, septum transversum, —> liver primordia ( becoming HEPATIC SINUSOIDS)
Right part of liver, veins become HEPATOCARDIAC CHANNEL —> IVC
Inferior vitelline veins become
Regress except some is left ——> portal vein, superior + inferior on mesenteric vein, Splanchnic vein
Umbilical veins travel how and connect to what
On either side of the liver and connect to hepatic sinusoid
*Left umbilical vein is the only one that stays and take blood from placenta to liver
Connection between what and what make the ductus venosus
The left umbilical vein and right hepatocardiac channel
DV bypass blood past the hepatic sinusoidal plexus
What happens to the left umbilical vein and ductus venosus after birth
The left umbilical vein —> LIGAMENTUM teres hepatis
The DV —> LIGAMENTUM venosum
Cardinal Vein join and enter what
The anterior and posterior Cardinal veins join (COMMON Cardinal vein) and then inter the sinus horn
Anterior Cardinal veins
Drain head and neck
Forms LEFT BRACHIOCEPHALIC VEIN
*most of left anterior cardinal vein regresses forming coronary sinus
SVC is formed from what
Right common cardinal vein
Abnormal anterior cardinal vein can cause
SVC to drain to the heart through the coronary sinus
Posterior Cardinal veins
2 of them
Subcardinal
Supracardinal
Subcardinal veins
Veins to kidney, and gonads
Forms ABD IVC
Supra cardinal veins
Veins draining body wall
Forms part of IVC and AZYGOS system
