7 - Development of Great Vessels Flashcards by Tyler Brown

Development of the Arterial System

1st month to 1st breath

Occurring at the same time with
expanding rest of body vessels

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Aortic Arches: Arise from the

aortic sac

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Aortic Arches: Terminate in the

right & left dorsal aortae

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Aortic Arches: Appear in a

cranial to caudal sequence & not all simultaneously

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Aortic Arches:

Aortic arch arteries, pharyngeal arch arteries and branchial (gill) arch arteries are all synonyms

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Note: right & left dorsal aortae fuse into a

single vessel from 4th thoracic region to 4th lumbar region

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1st arch

Regress – maxillary a.

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2nd arch

Regress – stapedial & hyoid aa.

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3rd arch

L/R common carotid, internal carotid, & external carotid aa.

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4th arch

Left: Part of aortic arch

Right: Part of the r. subclavian a.

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6th arch

Left: L. pulmonary a. & ductus arteriosus

Right: R. pulmonary a.

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7th segmental artery

Left: L. subclavian a.

Right: Part of r. subclavian a.

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Dorsal aorta

Left: Descending thoracic aorta

Right: Regress – part of r. subclavian a.

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Aortic sac*

Left: Part of aortic arch

Right: Brachiocephalic trunk

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Note that the arteries arising from the first three pairs of aortic arch arteries are

bilateral, whereas vessels derived from arches four and six develop asymmetrically

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Also note the aortic sac will form

right and left horns which will subsequently form the left/right adult derivatives

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Sixth arch is known as the

pulmonary arch.

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7th segmental artery will form the whole

left subclavian artery and part of the right subclavian

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Note the aortic sac forms

right and left horns which will subsequently form the left/right adult derivatives

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Part of right dorsal aorta

disappears
Heart moves into thoracic cavity; carotid & brachiocephalic aa. elongate; left subclavian shifts position
Course of recurrent laryngeal nn. becomes different on right and left

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Most somatic arteries of trunk develop from

intersegmental arteries from dorsal aorta

Develop:
Intercostal aa.
Lumbar aa

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Vitelline Artery: Initially are number of

paired vessels supplying the yolk sac

Will fuse to form arteries in dorsal mesentery of the gut

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Vitelline Artery: Develop into:

Celiac a. (trunk)

Superior mesenteric a.

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Umbilical Artery: Initially are paired

ventral branches off dorsal aorta; course to the placenta

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Umbilical Artery: Develop into:

Inferior mesenteric a.

Umbilical Artery: During week 4 also forms

secondary connection with dorsal aorta | Common iliac a.

Umbilical Artery: After birth, proximal portions persist as

internal iliac & superior vesical aa. | Distal parts are obliterated to form the median umbilical ligaments

Intersegmental arteries | derivatvies

Intercostal arteries | Lumbar arteries

Vitelline arteries derivatvies

Celiac trunk | Superior mesenteric artery

Umbilical arteries derivatvies

Inferior mesenteric artery Common iliac artery Proximal portion - Internal iliac artery & superior vesical artery Distal portion – Medial umbilical ligaments

Umbilical arteries derivatvies

Inferior mesenteric artery Common iliac artery Proximal portion - Internal iliac artery & superior vesical artery Distal portion – Medial umbilical ligaments

Great vessels derived from

Derived from epicardium

Connection to the aorta is formed by

ingrowth of arterial endothelial cells | This is how the coronary aa. “invade” the aorta

Embryonic Venous System: 3 pairs of

major veins All three systems are initially bilaterally symmetrical and converge on the right and left sinus horns of the sinus venosus. However, the shift of the systemic venous return to the right atrium initiates a remodeling that reshapes these systems to yield the adult patterns.

Embryonic Venous System: Vitelline veins

Drains GI tract & gut derivatives

Embryonic Venous System: Umbilical veins

Oxygenated blood from placenta to embryo

Embryonic Venous SystemCardinal veins

Draining head, neck, & body wall

Before entering sinus venosus, Vitelline veins forms

plexus around duodenum & pass through septum transversum

Liver cords growing into the septum interrupt the course & form

hepatic sinusoids

The network around the duodenum will form a

single vessel, the hepatic portal vein

These veins (vitelline veins) arise from

capillary plexuses of yolk sac & forms part of vasculature of gut & derivatives Initially drain into sinus horns of sinus venosus

A reduction in the l. sinus horn results in:

Rechanneling of blood from l. side of liver toward the right | Enlargement of r. vitelline duct

Enlargement of r. vitelline duct | Will form

part of the inferior vena cava

The superior mesenteric vein is also derived from the

r. vitelline vein

Right-left anastomoses remodeled to drain into the

portal vein | This is the splenic vein & inferior mesenteric vein

A single oblique channel among the hepatic anastomoses becomes

dominant and drains directly into the inferior cava. This is the ductus venosus which we will look at when we describe the umbilical vein derivatives

Persisting branches collect blood from the

abdominal foregut and the midgut.

Prominent left-to-right vitelline anastomoses are remodeled to deliver blood to the

distal end of the portal vein through two veins: the splenic vein and the inferior mesenteric vein.

R. umbilical vein will

regress and obliterate

L. umbilical vein will lose connection to

sinus horn & form ductus venosus

Bypasses the sinusoidal plexus of the

liver | Drains blood directly into the inferior vena cava

In contrast to the vitelline veins, in which the left regresses and the right persists, during the second month the right umbilical vein becomes

completely obliterated and the left umbilical vein persists

Ductus venosus is crucial during fetal life because it receives

oxygenated blood from the umbilical system and shunts it directly to the right vitelline vein and, hence, the right atrium

Left umbilical v. will become

ligamentum teres hepatis

Ductus venosus becomes

ligamentum venosum

This cardinal system is initially

bilaterally symmetrical

Anterior cardinal veins

Drain cephalic part of embryo

Posterior cardinal veins

Drain rest of embryo

Common cardinal veins

Ant. & post. cardinals join to form | Empty into sinus horns

Subcardinal veins & supracardinal veins will form to

supplement & later replace post. cardinal vv.

Posterior cardinal veins Major Derviatives

Common iliac veins | Sacral portion of IVC

Major Derviatives Anterior cardinal veins

Brachiocephalic veins Internal jugular vein External jugular vein

Major Derviatives Supracardinal veins

Intercostal veins Hemiazygos vein Azygos vein Segment of IVC inferior to kidneys

Major Derviatives Subcardinal veins

Renal veins Gonadal veins Renal segment of IVC

Major Derviatives | Common cardinal veins

Superior vena cava (from right common cardinal)

Fate of Posterior Cardinal Veins: Become obliterated over

most of their length

Fate of Posterior Cardinal Veins: Most caudal portions (including a large median anastomosis) persist & form a

new anastomosis with the supracardinals

Fate of Posterior Cardinal Veins: Caudal remnant develops into the

common iliac veins and the sacral portion of the IVC

The common iliac veins sprout the

internal and external iliac veins

Fate of Anterior Cardinal Veins: Cranial portions give rise to:

Internal jugular veins

Fate of Anterior Cardinal Veins: Capillary plexuses in the face become connected with

these vessels to form the external jugular veins

Fate of Anterior Cardinal Veins: Forms:

Brachiocephalic veins

Fate of Anterior Cardinal Veins: Superior vena cava is formed by

r. common cardinal & proximal portion of r. ant. cardinal

Anastomosis between the ant. cardinal vv. will develop into the

left brachiocephalic vein

Fate of Supracardinal Veins: Abdominal portions: | Inf. portion of l. supracardinal

obliterates

Fate of Supracardinal Veins: Abdominal portions: | R. supracardinal & subcardinal anastomose to form a

segment of the IVC just inf. to the kidneys

Thoracic portions: | Fate of Supracardinal Veins

Intercostal veins L. thoracic supracardinal Remaining portion of the inf. r. supracardinal drains into the heart.

Thoracic portions: Fate of Supracardinal Veins: L. thoracic supracardinal =

hemiazygos vein | Drains into the r.supracardinal system.

Thoracic portions: Fate of Supracardinal Veins Remaining portion of the inf. r. supracardinal drains into the

heart.

Fate of Supracardinal Veins take over the function of

posterior cardinals

Fate of Subcardinal Veins: Reorganization between the two subcardinals

Numerous median anastomoses & some lateral anastomoses | Forms the renal veins & gonadal veins

Fate of Subcardinal Veins: Longitudinal segments of the left subcardinal

regress

Fate of Subcardinal Veins: Right subcardinal loses its connection with the posterior cardinal vein and develops an

anastomosis with a segment of the right vitelline vein (inf. to heart)

Fate of Subcardinal Veins: Forms the portion of the

renal segment of IVC

Fate of Subcardinal Veins: Through the remodeling process blood from the organs originally drained by the right and left subcardinal veins now returns to the

right atrium via the IVC.

Development of Lymphatic System: 6 primary lymph sacs:

Jugular (2) Iliac (2) Retroperitoneal (1) Cisterna chyli (1)

Lymphatic vessels will connect to the

sac & pass along main veins

Sacs coalescing and segmenting – similar processes that we have seen with all of the

vascular developmental processes.

Right and left thoracic ducts initially connect the

jugular sacs with the cisterna chyli. Anastomosis forms between these channels

Thoracic duct = caudal right lymphatic duct + anastomosis of

left and right cranial thoracic ducts

Right lymphatic duct =

cranial portion of the right thoracic duct