Embryological Heart and Clinical Correlates

Question 1

Precursor of Aorticopulmonary Septum

Answer 1

truncal and bulbar ridges of neural crest cells through pharyngeal arches (ectoderm)

Question 2

Function of aorticopulmonary septum

Answer 2

partition of bulbis cords and trunks arteriosis via spiral growth

Question 3

Failure of aorticopulmonary septum to develop correctly

Answer 3

one outflow path from fused ventricles, or transportation of great arteries (straight line development)

Question 4

Transportation of Great Arteries

Answer 4

right ventricle to aorta with deoxygenated blood; left ventricle to pulmonary trunk with oxygenated blood. defect in aorticopulmonary septum

Question 5

Transportation of Great Arteries incompatible with life unless:

Answer 5

patent ductus arteriosus or foramen ovale or a VSD exists so that oxygenated blood in pulmonary trunk (if ductus arterosus present) can go to aorta and systemic system. foramen ovale or VSD would allow mixture of deoxygenated and oxygenated blood in atrium or ventricles, respectively, to provide some oxygenated blood to systemic system.

Question 6

most common VSD

Answer 6

membranous VSD

Question 7

Cause of membranous VSD

Answer 7

failure of bulbous ridges to fuse with endocardial cushions and close the intraventricular foramen.

Question 8

Clinical results of membranous VSD

Answer 8

initially a left to right shunt, causing pulmonary hypertension leading to pulmonary stenosis which reverses shunt and leaders to cyanosis to CHF and Eisenmenger’s Syndrom

Question 9

Failure of correct migration of neural crest cells from neural tube (ectoderm)

Answer 9

Tetralogy of Fallout, smaller pulmonary trunk (think secondary formed, so smaller) and overriding aorta, Transposition of Great Vessels

Question 10

4 Effects of Tetralogy of Fallout

Answer 10

1) overriding aorta
2) pulmonary stenosis which results in
3) right ventricle hypertrophy
4) VSD due to superior malalignment of sub pulmonary infundibulum

Question 11

Parts of the Primitive Heart

Answer 11

blood flows from sinus venous (sinus vernarum and coronary sinus) to primitive atrium (auricles of right and left atria) to primitive ventricle (left ventricle) to bulbis cordis (right ventricle) to conus cordis (conus arteriousus and aortic vestibule) to truncus arteriosus (ascending aorta and pulmonary trunk) to aortic arch

Question 12

Conus cordis

Answer 12

upper bulbis cords that splits into conus arteriousus (for right ventricle to pulmonary trunk) and aortic vestibule (for left ventricle to aorta)

Question 13

ASDs

Answer 13

sinus venosis, probe patencey foramen ovale/ AV canal, foramen secundum, common atrium

Question 14

Probe Patency of foramen ovale/AV Canal

Answer 14

not clinically relevent– failure to fuse septum premium and second, maintaining foramen ovalis,

Question 15

Foramen secundum ASD

Answer 15

excessive reabsorption, most common, clinically significant

Question 16

Common Atrium

Answer 16

complete failure for foramen secondum or primum to develop

Question 17

Ectopia Cordis

Answer 17

faulty development of stream and pericardium due to incomplete fusion of lateral folds, cardiac failure, hypoxema. incompatible with life

Question 18

Right Sinus venosus splits into

Answer 18

sinus venarum (smooth part of right atrial wall… incorporated in primitive atrium) and coronary sinus

Question 19

Sinus venarum

Answer 19

pushes pectinate muscles into right half ventral part of primitive atrium, resulting in right auricle and becomes incorporated in wall of atrium.

Question 20

Original right side of primitive atrium

Answer 20

right auricle

Question 21

Left atrial wall (grows out, grows in)

Answer 21

incorporation of primitive pulmonary veins (split of the original pulmonary vein) gives it a smooth appearance

Question 22

left auricle

Answer 22

pectinate muscles displaced by the incorporation of primitive pulmonary veins into left atrial wall.

Question 23

Pressure switches in primitive atrium and septum closure

Answer 23

Initially, right atrium high pressure keeping flimsy septum primum away from rigid septum secundum due to umbilical vein supply being larger than the pulmonary supply (not needed for fetal lungs). first breath, lungs need oxygenated blood, pressure switch (left more than right) sealing the septum primum to septum secundum becoming the fossa ovalis

Question 24

Bending of heart tube results in:

Answer 24

shifting of sinus venous into right and left horns to empty in to the right atrium via coronary sinus or septum vernarum (superior vena cava)

Question 25

Only source of oxygenated blood into the sinus venosus

Answer 25

Umbilical veins from mother

Question 26

3 ways blood enters sinus venosus

Answer 26

``` common cardinal veins (anterior/cranial; posterior/caudal) umbilical veins (oxygenated) vitelline veins (deoxygenated) all come into the heart caudally via sinus venosus ```

Question 27

caudal and rostral anchor of the primitive heart

Answer 27

caudal-sinus venosus, central tendon of diaphragm | rostral--neck walls

Question 28

endocardial cushions

Answer 28

divide AV canal into right and left atrioventricular openings

Question 29

fusion of endocardial cushions

Answer 29

AV septum, preventing mixture of oxygenated and deoxygenated blood

Question 30

endocardial cushions participate in the formation of

Answer 30

membranous portion of IV septum, closure of foramen primum (helps complete both IV and AV septum)

Question 31

muscular part of IV septum

Answer 31

muscular upgrowth from primitive ventricle

Question 32

membranous portion of IV septum

Answer 32

endocardial tissues/endocardial cushions and bulbar ridges (so bulbus is more caudal than truncus)

Question 33

Primary Intraembryonic Arteries

Answer 33

Paired dorsal aortae Intersegmental arteries between somites Aortic arch arteries

Question 34

Primary Embryonic Veins

Answer 34

cardinal system of veins, and this mixes with umbilical vein

Question 35

Placenta Bloodflow to Embryo

Answer 35

Umbilical vein

Question 36

Yolk Sac blood blow

Answer 36

Vitelline veins

Question 37

What is important about the vitelline vein?

Answer 37

first source of blood cells in the embryonic circulation

Question 38

what vessel brings embyronic blood back to the heart

Answer 38

cardinal veins

Question 39

Where/what happens to the dorsal aorta

Answer 39

Caudally fuse together to form descending aorta

Question 40

what occurs at the rostral end of the embryo in vessel development

Answer 40

truncus arteriousus is continuous cranially with aortic sac, which is produce the pharyngeal arch arteries. aortic arches connect aortic sac to the dorsal aortae

Question 41

what is the purpose of the caudal umbilical arteries during vessel development?

Answer 41

the develop in the connecting stalk to link the dorsal aortae to the capillaries in the chorionic villi

Question 42

role of the vitilline arteries in the vessel formation

Answer 42

connected to the dorsal aortae, make a capillary connection to the yolk sack, and become the digestive system arteries (celiac, superior mesenteric, inferior mesenteric)

Question 43

what are the digestive system arteries from cranial to caudal

Answer 43

celiac, superior, and inferior mesenteric

Question 44

connects to the dorsal aortae by aortic arches

Answer 44

aortic sac

Question 45

dorsal aortae to chorionic vessels

Answer 45

umbilical arteries

Question 46

6 pharyngeal arches suppled by arteries called

Answer 46

aortic arch

Question 47

aortic arches arise from _____, and this gives rise to

Answer 47

aortic arches arise from aortic sac, which gives rise to the brachiocephalic artery, and the right side of the aortic arch

Question 48

what happens to first and second aortic arches

Answer 48

regress

Question 49

what happens to third aortic arch

Answer 49

common carotid arteries, and proximal internal carotid

Question 50

what happens to fifth aortic arch

Answer 50

there is not a fifth aortic arch

Question 51

internal carotid is formed by

Answer 51

third aortic arch (proximal) and remainder of upper end of dorsal aorta (distal)

Question 52

external carotids

Answer 52

sprout from internal carotids

Question 53

lose dorsal aorta

Answer 53

between 3 and 4 arches on both sides, but also distal to the 7th intersegmental artery (forms the subclavian)

Question 54

what does the 7th intersegmental artery form

Answer 54

subclavian

Question 55

dorsal aorta persists on right side and left side to form

Answer 55

dorsal aorta persists on right side to form the medial portion of right subclavian (distal portion is 7th intersegmental arch), persists on left to from the descending thoracic aorta, which the left 7th intersegmental arch branches from to form the left subclavian artery

Question 56

4th aortic arch

Answer 56

left side is the aortic arch | right side is the proximal subclavian artery

Question 57

6th aortic arch

Answer 57

right side is the right pulmonary artery | left side is the left pulmonary artery and the ductus arteriousus

Question 58

proximal part of internal coratid artery

Answer 58

3rd aortic arch

Question 59

a portion of the aortic arch is dervived from

Answer 59

4th aortic arch

Question 60

position of recurrent laryngeal nerves in accordance to development

Answer 60

on right side, distal part 6th aortic arch regresses, so the RLN stays with subclavian left side, distal part of 6th aortic arch remains as ductus arteriousus, so it is brought down with aorta

Question 61

rib notching

Answer 61

caused by postductal/distal coarctation of aorta which promotes development of extensive collateral circulation to get blood to descending aorta

Question 62

subcardinal veins

Answer 62

from posterior cardinal veins and drain mesoneophric kidneys, join at mid line to form a venous H

Question 63

4 components of diaphragm

Answer 63

pleuroperitoneal membranes, central tendon of diaphragm (septum transversum), myoblasts from lateral body walls (skeletal muscle), and dorsal mesentary of diaphragm (crura)

Question 64

precursor to gonadal veins

Answer 64

caudal subcardinal after the formation of the RCI/LCI

Question 65

hepatic segment

Answer 65

right subcardinal joint the vitelline duct

Question 66

renal segment of IVC

Answer 66

distal subcardinal, before hepatic segment

Question 67

left renal vein

Answer 67

anastomosis of the subcardinal veins

Question 68

RCI/LCI

Answer 68

right sacrocardinal for RCI | anastomosis of sacrocardinal for LCI

Question 69

precursor to left bracheocephalic vein

Answer 69

anterior cardinal veins

Question 70

function of the left bracheocephalic in embryo

Answer 70

shunt blood from left to right anterior cardinal vein

Question 71

what forms the superior vena cava

Answer 71

right anterior cardinal vein and right common cardinal vein

Question 72

precursors to azygous vein, hemiazygous vein, accessory hemiazygous vein

Answer 72

AZ-right supracardinal vein HZ-caudal left supracardinal vein AHZ- cranial left supracardinal vein

Question 73

portal vein

Answer 73

anastomosis of vitelline veins around the duodenum

Question 74

definitive umbilical vein

Answer 74

the dominate, left umbilical vein, returns all of the blood from the placenta

Question 75

ductus venosus

Answer 75

an anastomosis via hepatic sinusoids between umbilical vein and proximal right vitelline vein