Embryo 4

Question 1

Vasculogenesis

Answer 1

• formation of new vascular channels by assembly of individual cells precursors called angioblast or hemoangioblast
• from mesoderm

Question 2

Mesenchyme

Answer 2

embryonic CT

Question 3

Angiogenesis

Answer 3

development of blood vessels from pre-existing vessels (adults/cancer)

Question 4

Arteriogenesis

Answer 4

remodeling of existing arteries in response to different pathological/physiological changes

Question 5

What two cells do angioblasts give rise to?

Answer 5

1. Hematopoeitic stem cells

2. Endothelial precursor cells

Question 6

When does vasculogenesis begin?

Answer 6

end of third week

Question 7

Where are Hematopoeitic stem cells formed?

Answer 7

AGM

Question 8

What do blood islands produce?

Answer 8

Plexuses

*channels form within the plexuses, and these channels then enlarge/unite to form arteries and veins

Question 9

Angioma

Answer 9

1. Capillary Hemagioma (nevus vascular): excessive growth of small capillary networks->cherry angiomas (campbell de morgan spots)
2. Cavernous Hemagioma: proliferation of large dilated vascular channels
3. Hemangioma of infancy: benign tumor; consists of many endothelial cells (due to v asculogenesis; enlarge birth -one year, and then many will regress

Question 10

Infants with segmental hemangioma should also be evaluated for…

Answer 10

PHACE syndrome

Question 11

What are the three branches of the fused dorsal aorta?

Answer 11

1. Ventral Segmental Arteries
2. Lateral Segmental Arteries
3. Dorsal Segmental Arteries

Question 12

What do Ventral Segmental Arteries supply?

Answer 12

splanchnic layer of lateral plate mesoderm and endoderm (ex. IMA, SMA)

Question 13

What do Lateral Segmental Arteries supply?

Answer 13

intermediate mesoderm derivatives (ex. renal, ovarian, and testicular arteries)

Question 14

What do Dorsal Segmental Arteries supply?

Answer 14

derivatives of somites; when they come off we call them intersegmental arteries (ex. intercostal and lumbar arteries)

Question 15

What does the first formed aortic arch supply?

Answer 15

first pharyngeal arch

Question 16

What forms day 26-32? 32-37?

Answer 16

1. rudiments of remaining aortic arches (as 3 forms, 1 degenerates; 4, 2…)
2. completion of aortic arches; send a lot of branches to the head

Question 17

Derivatives of aortic arches: 1st

Answer 17

external carotid, maxillary

Question 18

Derivatives of aortic arches: 2nd

Answer 18

stems of stapedial arteries

Question 19

Derivatives of aortic arches: 3rd

Answer 19

common carotid, internal carotid

Question 20

Derivatives of aortic arches: Aortic sac

Answer 20

brachiocephalic artery, base of arch of aorta

Question 21

Derivatives of aortic arches: 4th

Answer 21

left: medial portion of arch of aorta
right: proximal right subclavian

Question 22

Derivatives of aortic arches: 6th

Answer 22

pulmonary arteries

• left: distal ductus arteriosus
• right distal degenerates

Question 23

Derivatives of aortic arches: 7th intersegmental arteries

Answer 23

right: distal part of right subclavian
left: entire left subclavian

Question 24

Derivatives of aortic arches: dorsal aorta

Answer 24

right: portion of right subclavian artery
left: descending aorta

Question 25

Fetal Blood Circulation

Answer 25

O2 blood from placenta-->left umbilical vein-->liver-->ductus venous-->inferior vena cava-->right atrium-->foramen ovale/secundum-->left atrium-->left ventricle--> aorta-->branches going to head/descending aorta

Question 26

What happens if theres too much blood coming form the placenta?

Answer 26

sphincter constructs, and directs blood into the sinusoids of the liver

Question 27

What three things do we get with aeration of the lungs?

Answer 27

1. Decrease in pulmonary vascular resistance 2. Increase in pulmonary blood flow 3. Thinning of walls of pulmonary arteries

Question 28

What is the round ligament of liver/ligamentum teres?

Answer 28

remnant of the left umbilical vein

Question 29

Where does ligamentum arteriosum come from?

Answer 29

- ductus arteriosus fuses within 72 hours after birth | - due to increased prostaglandins and bradykinin

Question 30

Coarctation of Aorta

Answer 30

- due to aortic constriction (above/below ductus arteriosus) - normal/high pulses/BP of UE; low/absent for LE a. Preductal: can become cyanotic (prostaglandins are given, so duct arteriosus doesn't close) b. Postductal: fetus often develops collateral system (angiogenesis) *due to smooth muscle abnormally goes into aorta, and constricts OR aortic arches remodeled, and narrowed

Question 31

Double Aortic Arch

Answer 31

- persistence of distal portion of right dorsal aorta (normally it becomes right subclavian, and the rest degenerates) - vascular rings forms around the trachea/esophagus - symptoms: stridor, respiratory infections/distress, wheezing, cough, esophageal complains (dysphagia, feeding difficulty, vomiting)

Question 32

Interrupted Aortic Arch

Answer 32

- both right and left 4th aortic arch arteries are obliterated - distal right dorsal aorta is retained; normally have VSD and PDA - Symptoms (day 1-2): weakness, fatigue, poor feeding, false HR, low O2 levels (especially legs) - associated with DiGeorge Syndrome *right side always gets O2; left side is variable

Question 33

What is the most severe form of a coarctation of the aorta?

Answer 33

Interrupted Aortic Arch

Question 34

Abnormal Origin of the Right Subclavian Artery

Answer 34

- arises from the distal part of the right dorsal aorta, and the 7th intersegmental artery - the right 4th aortic arch, and the proximal part of the right dorsal aorta obliterate - right subclavian passes behind the esophagus and trachea - some people are asymptomatic, and some have esophageal problems - may see lower pulse in right UE than left because the Rt. subclavian can get compressed on by the vertebral bodies

Question 35

Right Aortic Arch

Answer 35

- the left fourth arch and left dorsal aorta are obliterated and replaced by the corresponding vessels on the right side - swallowing can be impaired if ligamentum arteriosum lies on the left side and passes behind the esophagus

Question 36

What are the three sets of veins?

Answer 36

1. Cardinals (anterior, posterior, common): O2 poor blood from body back to heart 2. Vitelline (around yolk sac/liver): O2 poor blood from body back to heart 3. Umbilical: O2 rich blood from placenta back to heart

Question 37

Vitelline Veins

Answer 37

- proximal to heat: left: degenerates; right persists | - within liver: right forms hepatic vein (part of inferior vena cava); right and left form portal vein (from gut)

Question 38

Umbilical Veins

Answer 38

- Right degenerates entirely - Left persists: brings O2 rich blood from placenta back to heart a. Proximal degenerates b. Anastomoses with ductus venosus c. Distal persists in embryo providing placental return

Question 39

Cardinal Veins

Answer 39

a. Anterior: drainage from cranial territory - right forms internal jugular and superior VC - left forms left brachiocephalic b. Posterior: drainage from body wall - degenerate except fro root of azygos and common iliac; replaced by sub cardinal and supra cardinal veins

Question 40

Venous System Defects: left superior vena cava

Answer 40

-persistence of left anterior cardinal vein and obliteration of the common cardinal and proximal part of the anterior cardinal veins on the right

Question 41

Venous System Defects: double superior vena cava

Answer 41

-persistence f the left anterior cardinal vein and failure of the left brachiocephalic vein to form

Question 42

Inferior Vena Cava 1. Hepatic segment 2. Prerenal 3. Renal 4. Postrental 5. Malformations

Answer 42

1. right vitelline/hepatic veins and sinuses 2. right sub cardinal 3. sub cardinal-supracardinal anastomosis 4. right supra cardinal 5. Persistence of a sacrocardinal vein (2 inferior VCs)