Embryology

Question 1

forms the primordium of the heart (muscular wall), conduction system, inflow tract

Answer 1

LP splanchnic mesoderm

Question 2

earliest sign of development of the heart

Answer 2

paired angioblastic cords (paired endothelial strands)
these fuse to form a single tube that folds back on itself (beginning around day 23) to become the 4 chambers of the heart

Question 3

when heart begins to beat

Answer 3

day 22-23

Question 4

forms the fibrous cardiac skeleton, valves, cardiac cushions, atrial & membranous ventricular septa, outflow tract (bulbus cordis and truncus arteriosus) chordae tendinae

Answer 4

neural crest

Question 5

what forms the hepatic portal system

Answer 5

right vitelline vein

note: the left vitelline vein regresses

Question 6

Where does the umbilical vein deliver oxygenated blood from the placenta early in development?

Answer 6

sinus venosus

umbilical veins lose their connection with the heart as the embryo develops and empty into the liver

Question 7

Which umbilical vein disappears during the 7th week of gestation?

Answer 7

right

left umbilical vein remains to carry oxygenated blood from placenta

Question 8

What connects the umbilical vein to the inferior vena cava?

Answer 8

ductus venosus

this helps most of the oxygenated blood to bypass the liver and pass directly to the heart

Question 9

most common anomaly of IVC in the adult?

Answer 9

IVC is interrupted in its course and blood drains from the lower limbs, abdomen and pelvis to the heart through the azygos veins

Question 10

right to left shunt caused by persistence of left anterior cardinal vein

Answer 10

persistent left SVC

the SVC is normall formed by the right anterior cardinal vein and right common cardinal vein

Question 11

degeneration of the right anterior cardinal vein and right common cardinal vein, leaving blood to enter the SVC and then the coronary sinus via the left brachiocephalic vein

Answer 11

left superior vena cava

Question 12

inferior part of left supracardinal vein persists

Answer 12

double inferior vena cava

Question 13

become the internal iliac arteries and superior vesicle arteries (to urinary bladder)

Answer 13

proximal parts of the umbilical arteries

Question 14

becomes the endocardium

Answer 14

endothelial tube

Question 15

forms the epicardium

Answer 15

mesothelial cells that arise from the external surface of the sinus venosus

Question 16

forms the aortic arches

Answer 16

LP splanchnic mesoderm

Question 17

What composes the truncus arteriosus and bulbis cordis?

Answer 17

neural crest

Question 18

becomes the foramen ovale

Answer 18

septum secundum

Question 19

What makes the valve of the foramen ovale?

Answer 19

septum primum

Question 20

anatomical closure of the foramen ovale occurs when?

Answer 20

around 1 year

Physiological closure occurs after birth when pressures rise on the left side of the heart

Question 21

most common ASD

Answer 21

probe patent foramen ovale

Question 22

causes right ventricular hypertrophy

Answer 22

ostium secundum defect

Question 23

forms from the bulbus cordis

Answer 23

conus arteriosus (right ventricle) and aortic vestibule (left ventricle)

Question 24

caused by the spiraling failing to occur

Answer 24

transposition of the great arteries

death within a few days or months without surgical intervention

Question 25

How does IV septum form?

Answer 25

fusing of left and right bulbar ridges with the endocardial cushion

Question 26

splanchnic mesoderm problem

Answer 26

low VSD

Question 27

neural crest problem

Answer 27

high VSD, ASD

Question 28

neural crest and splanchnic mesoderm problem

Answer 28

common ventricle

Question 29

forms the adult renal veins

Answer 29

subcardinal-supracardinal anastomosis

Question 30

becomes the coronary sinus

Answer 30

left horn of the sinus venosus

Question 31

contain the pectinate muscles

Answer 31

the auricles of the atria

Question 32

carotid arteries form from which aortic/pharyngeal arch

Answer 32

3rd

Question 33

arch of aorta, R brachiocephalic artery & proximal subclavian form from which aortic/pharyngeal arch

Answer 33

4th

Question 34

which aortic/pharyngeal arch degenerates?

Answer 34

5th

Question 35

which aortic arch/pharyngeal arch becomes the pulmonary arteries and ligamentum arteriosum

Answer 35

6th

Question 36

3rd and 4th pharyngeal pouches fail to differentiate into the thymus and parathyroid glands, leading to facial abnormalities and susceptibility to infection. deletion on chromosome 22q11

Answer 36

DiGeorge Syndrome

Question 37

embryonic heart tube bends toward the left instead of the right, displacing the heart to the right and reversing the heart and its vessels to a mirror image or the normal configuration heart function is normal

Answer 37

dextrocardia if transposition of the abdominal viscera accompanies it: dextrocardia with situs inversus

Question 38

heart is partially or completely exposed on the surface of the thorax associated with cleft sternum and open pericardial sac death within a few days of birth

Answer 38

ectopic cordis