1 - Development of Great Vessels Flashcards
How is the heart initially connected to the paired dorsal aorta?
What embryological structure is the aortic sac the rostral part of?
What occurs to this pair of vessels during development?
By paired aortic arches from the aortic sac
Truncus Arteriosus
The paired dorsal aortae fuse to form single aorta
What are the branches of the fused single aorta?
- Paired intersegmental arteries
- Unpaired Vitelline arteries
- Paired umbilical arteries
- Paired Lateral splanchnic arteries
Where do the paired intersegmental arteries grow?
Where do they supply blood?
What do they form in the mature body (from what intercostal spaces)?**
Grow between somites
Supply blood to body wall
- Posterior Intercostal and Lumbar Arteries (part of right / left subclavian A.’s) - 7th Intersegmental - Upper Extremity
- Common Iliac Arteries - 5th Lumbar Intersegmental - Lower Extremity
What structures do the unpaired vitelline arteries supply?
What vessels do they form in the mature body?
Yolk Sac (primitive gut) derivatives
- Esophageal and Bronchial Arteries
- Celiac, Superior/Inferior Mesenteric
What do the Paired Umbilical Arteries branch off?
What do they become in the mature body?
Branch off 5th Lumbar Intersegmental Artery (future Common Iliac)
- Internal Iliac Arteries
- Superior Vesicle Artery (bladder)
- (Not artery) Medial Umbilical Ligament
What is the fate of aortic carches 1, 2, and 5?
What do aortic arches 1 and 2 form?
They degenerate
Part of Maxillary A. and Stapedial A.
What does Aortic Arch 3 from?
What occurs to the dorsal aortae connecting Arches 3 and 4?
Proximal - Forms Common Carotid Artery
Distal + oart of dorsal Aorta form Internal Carotid Artery, External Carotid Artery
They degenerate
What does the Left Aortic Arch 4 form?
What does the Right Aortic Arch 5 form?
Left - Arch of the Aorta (with Aortic Sac / Left Dorsal Aorta)
Right - Right Subclavian Artery (with Right Dorsal Aorta / Right 7th Intersegmental Artery)
What three embryonic vessels for the Arch of the Aorta?
What three embryonic vessels for the Right Subclavian?
What forms the Left Subclavian?
Arch of Aorta: Left Aortic Arch 4, Aortic Sac, Left Dorsal Aorta
Right Subclavian: Right Aortic Arch 4, Right Dorsal Aorta, Right 7th Intersegmental Artery
Left Subclavian: Left 7th Intersegmental Artery
What does the Proximal part of Aortic Arch 6 form?
What does the Distal part of Aortic Arch 6 form?
Proximal - Left and Right Pulmonary Arteries
Distal - Right degenerates, Left persists as ductus arteriosus
What are the two fetal bypasses of pulmonary circulation?
What occurs to these following birth?
- Foramen Ovale connecting RA and LA
- Ductus Arteriosus connecting Left Pulmonary Artery to Arch of Aorta
- - - - Foramen Ovale closes (normal) due to reversal of Pressure Gradient
- Ductus Arteriosus smooth muscle wall constrict, closing off. Becomes Ligamentum Arteriosum
What forms the braciocephalic trunk?
Aortic Sac
What is the fate of the causal part of right dorsal aorta bwteen the 7th Intersegmental Artery and the fused right and left dorsal aortae?
Shit go bye bye
What nerve supplies the 6th Pharyngeal Arch?
Recurrent laryngeal nerve of the vagus nerve
What is the fate of the right recurrent laryngeal nerve?
What structure does it hook around?
Due to the 6th/5th Aortic Arch degeneration on the right, it hooks around the 4th which forms the right subclavian artery
This is how the Right Recurrent Laryngeal Nerve hooks around the Right Subclavian Artery
What is the fate of the left recurrent laryngeal nerve?
Left 6th Arch persists as ductus arteriosus
Left Recurrent Laryngeal hooks around the mature form of this, the Ligamentrum Arteriosus as well as the Arch of the Aorta
Left Hooks Ligamentum Arteriosus
Clinical: Postductal Coarctation of the Aorta
How does blood reach structures?
What is a clinical presentation?
Narrowing of the Aorta
Postductal = Narrowing inferior to ductus arteriosus (normally closed)
Most Common
- - -
For blood to reach inferior structures, collateral circulation develops in 2 locations
1. Anterior Intercostal Branchs of Internal Thoracic + Posterior Intercostals of Aorta
2. Superior Epigastric + Inferior Epigastric
- - -
Often asymptomatic, but xrays may show rib-notching
Clinical: What anastomes must form to provide inferior circulation to a Postductal Coarctation Aortic narrowing?
- Anterior Intercostal Branchs of Internal Thoracic + Posterior Intercostals of Aorta
- Superior Epigastric + Inferior Epigastric
Clinical: Preductal Coarctation
Narrowing of aorta superior to ductus arteriosus
Ductus Arteriosis remains patent to supply aorta with blood
Clinical: Patent Ductus Arteriosus
At Risk Population?
When surgically correcting, what is a complication you need to avoid?
Failure of clusure of the ductus post-natally
Results in shunting of blood from aorta (high pressure) to pulmonary artery (low pressure)
At Risk: Premature Infants, Mothers with Rubella
During surgery you have to watch for Left Recurrent Laryngeal Nerve (permanent hoarse voice)
Clinical: Abnormal Right Subclavian Artery
Symptoms?
Cause?
Abnormal branch of aortic arch, passes posterior to esophagus
Can result in kinking of the esophagus, difficulty swalling
Cause:
Obliteration of right 4th aortic arch and adjacent part of rt dorsal aorta (between 4th and 7th)
Forms from right 7th intersegmental artery and persistence of distal part of right dorsal aorta (which normally degenerates)
Clinical: Double Aortic Arch
Abnormal right arch develops in addition to left
Due to persistence of distal part of right dorsal aorta
Forms vascular ring around trachea and esophagus causing difficulty in swallowing or breathing
Clinical: Right Aortic Arch
Can oass anterior or posterior (retroesophageal) to the esophagus and trachea
Retroesophageal Right Arch can cause difficulties in swallowing or breathing
Due to persistence of entire right dorsal aorta and degeneration of distal part of left dorsal aorta
What are the major three pairs of embryonic veins?
What type of flow occurs during embryonic development?
Vitelline Veins
Umbilical Veins
Cardinal Veins
Left-to-Right Shunting of blood to right atrium
What do the right and left Vitelline Veins drain?
What definitive structures do they form?
What is the ultimate fate of each of the two veins?
Primitive Gut
Form: Hepatic Sinusoids (liver channels), Ductus Venosus
Right: Forms part of Inferior Vena Cava and Hepatic Portal System
Left: Degenerates due to L-to-R shunting post-natally
What is the purpose of the Ductus Venosus during natal development?
What does it form post natally?
Venous by-pass of developing liver and a L-to-R shunt to Right Atrium
Shunts fblood from left umbilical vein to inferior vena cava
Forms Ligamentum Venosum post natally
What is the fate of the Left and Right paired Umbilical Veins?
Right: Degenerates
Left: Fetal - carries oxygenated placental blood, goes to liver–drains into Hepatic Sinusoids and (via Ductus Venosus) drains into Inferior Vena Cava
Post Natal: Left forms Ligamentum Teres Hepatis
Why is the liver mostly bypassed during development?
How does this occur?
Blood is already ‘processed’ by mother
Ductus Venosus shunts oxygen rich blood into inferior cava for distribution by heart
What is the developmental purpose of the Three Cardinal Veins?
What is the fate of the Right and Left Anterior Cardnial Veins?
What forms the Superior Vena Cava?
What is the fate of the Posterior Cardinal Vein?
Anterior / Posterio drain Cephalic and Caudal early embryo into the Common Cardinal V. , which drains into Sinus Venosus
- - -
R/L Anterior Cardinal Veins: Contribute to Internal Jugular V., become connected by Oblique ansatomosis–which become Left Brachiocephalic Vein
Right also conributes to Right Brachiocephalic V.
- - -
R. Anterior Cardinal + R. Common Cardinal form Superior Vena Cava
Mostly degenerate; form segment of Inferior Vena Cava and Common Iliac Veins
Clinical: Double Superior Vena Cava
Terminal L. Ant. Cardinal vein normally degenerates sticks around to be a dick
Clinical: Left Superior Vena Cava
Terminal L. Ant. Cardinal V. normally degenerates, but terminal R. Ant. Cardinal V. degenerates instead–
results in a Left Superior Vena Cava
Prenatal: Left Umbilical Vein
Postnatal: ?
Postnatal: Ligamentum teres Hepatis
Prenatal: Ductus Venosus
Postnatal: ?
Postnatal: Ligamentum Venosum
Prenatal: Foramen Ovale
Postnatal: ?
Postnatal: Fossa Ovalis (closes foramen)
Prenatal: Ductus arteriosis
Postnatal: ?
Postnatal: Ligamentum Arteriosum
Prenatal: Umbilical Artery
Postnatal: ?
Postnatal: Gives rise to Internal Iliac A., Superior Vesicle A., Medial Umbilical Ligament
