Cardio FA - Embryo p 278-280

Question 1

Bulbus Cordis gives rise to?

Answer 1

Smooth parts (outflow tract) of left and right ventricles

Question 2

Endocardial cushion gives rise to?

Answer 2

Atrial septum, membranous inter ventricular septum, AV and semilunar valves

Question 3

Left horn of sinus venosus gives rise to?

Answer 3

Coronary sinus

Question 4

Posterior, sub cardinal, supracardinal vein gives rise to?

Answer 4

IVC

Question 5

Primitive Atrium gives rise to?

Answer 5

Trabeculated part of left and right atria

Question 6

Primitive pulmonary vein gives rise to?

Answer 6

Smooth part of left atrium

Question 7

Primitive ventricle gives rise to?

Answer 7

Trabeculated part of left and right ventricles

Question 8

Right common cardinal vein and right anterior cardinal vein gives rise to?

Answer 8

SVC

Question 9

Right horn of sinus venosus gives rise to?

Answer 9

Smooth part of right atrium (sinus venarum)

Question 10

Truncus arteriosus gives rise to?

Answer 10

Ascending aorta and pulmonary trunk

Question 11

Primary heart tube loops to establish left and right polarity at what week of gestation?

Answer 11

Week 4

Question 12

Defect in cardiac looping leads to what?

Answer 12

Defect in left-right Dynein ( involved in L/R asymmetry) can lead to dextrocardia as seen in Kartagener syndrome aka primary ciliary dyskinesia

Question 13

Septation of chambers in the atria name the 7 steps ? ( sorry for the length)

Answer 13

1-Septum primum grows toward endocardial cushions, narrowing foramen primum. 2-Foramen secundum forms in septum primum (foramen primum disappears). 3-Septum secundum develops as foramen secundum maintains right-to-left shunt. 4-Septum secundum expands and covers most of the foramen secundum. The residual foramen is the foramen ovale. 5-Remaining portion of septum primum forms valve of foramen ovale. 6. (Not shown) Septum secundum and septum primum fuse to form the atrial septum. 7. (Not shown) Foramen ovale usually closes soon after birth because of increased LA pressure and and decreased RA pressure.

Question 14

What is the cause of Patent Foramen Ovale and what does it lead to?

Answer 14

caused by failure of septum primum and septum secundum to fuse after birth; most are left untreated. Can lead to paradoxical emboli (venous thromboemboli that enter systemic arterial circulation), similar to those resulting from an ASD.

Question 15

Name the 3 steps for separation of ventricles

Answer 15

1-Muscular interventricular septum forms. Opening is called interventricular foramen. 2-Aortico-pulmonary septum rotates and fuses with muscular ventricular septum to form membranous interventricular septum, closing interventricular foramen. 3- Growth of endocardial cushions separates atria from ventricles and contributes to both atrial septation and membranous portion of the interventricular septum.

Question 16

Most common congenital cardiac anomaly, usually occurs in membranous septum?

Answer 16

VSD

Question 17

Outflow tract formation how?

Answer 17

Neural crest and endocardial cell migrations–>>> truncal and bulbar ridges that spiral and fuse to form aorticopulmonary septum —>>> ascending aorta and pulmonary trunk.

Question 18

Name 3 Conotruncal abnormalities associated with failure of neural crest cells to migrate?

Answer 18

• Transposition ofgreat vessels. • Tetralogy of Fallot. • Persistent truncus arteriosus.

Question 19

Heart Valves development derived from where?

Answer 19

Aortic/pulmonary: derived from endocardial cushions of outflow tract. Mitral/tricuspid: derived from fused endocardial cushions of the AV canal.

Question 20

Name a few common valvular anomalies which are commonly seen?

Answer 20

Valvular anomalies may be stenotic, regurgitant, atretic (eg, tricuspid atresia), or displaced (eg, Ebstein anomaly).

Question 21

Umbilcal vein vs Umbilical Artery ( in terms of differences in O2 saturation)

Answer 21

Blood in umbilical vein has a Po2 of = 30 mm Hg and is = 80% saturated with 0xygen. Umbilical arteries have low 0xygen saturation

Question 22

Name the 3 important shunts in fetal circulation?

Answer 22

1-) Blood entering fetus th rough the umbilical vein is conducted via the ductus venosus into the IVC, bypassing hepatic circulation. 2-) Most of the highly Oxygenated blood reaching the heart via the IVC is directed through the foramen Ovale and pumped into the aorta to supply the head and body. 3-) Deoxygenated blood from the SVC passes through the RA–>RV–> main pulmonary artery—>Ductus arteriosus—> Descending aorta; shunt is due to high fetal pulmonary artery resistance (due partly to low 0xygen tension).

Question 23

What happens when baby takes 1st breath?

Answer 23

At birth, infant takes a breath —>decreases resistance in pulmonary vasculature—>>> Leading to increase left atrial pressure vs right atrial pressure—-> foramen ovale closes (now called fossa ovalis); increase in Oxygen (from respiration) and decrease in prostaglandins (from placental separation) - closure of ductus arteriosus.

Question 24

What closes a PDA?

Answer 24

indomethacin ( PDA becomes ligamentum arteriosum–remnant of PDA)

Question 25

What keeps PDA open?

Answer 25

PGE1, PGE2

Question 26

allantois becomes what?

Answer 26

median umbilical ligament

Question 27

What is the urachus part of and found where?

Answer 27

urachus is part of allantoic duct b/w bladder and umbilicus

Question 28

postnatal remnant of ductus arteriosus?

Answer 28

ligamentum arteriosum

Question 29

postnatal remnant of ductus venosus?

Answer 29

ligamentum venosum

Question 30

postnatal remnant of foramen oval?

Answer 30

fossa ovalis

Question 31

postnatal remnant of notochord?

Answer 31

nucleus pulposus

Question 32

postnatal remnant of umbilical arteries?

Answer 32

Medial umbilical ligaments

Question 33

postnatal remnant of umbilical vein? where is this remnant found?

Answer 33

Ligamentum teres hepatis ( aka round ligament) contained in the faliciform ligament

Question 34

When does the heart begin to form in embryo?

Answer 34

week 4

Question 35

What is the tissue of origin of the heart?

Answer 35

Embryonic mesoderm

Question 36

Embryonic origin of coronary sinus?

Answer 36

left horn of sinus venosus

Question 37

Causes a harsh holosystolic murmur?

Answer 37

VSD - most common congenital heart anomaly,

Question 38

Due to failure of neural crest cells to migrate?

Answer 38

Transposition of great vessels Tetralogy of Fallot Persistent truncus arteriosus

Question 39

What is the O2 saturation of umbilical vein/arteries?

Answer 39

Vein = 80% saturation, A= very low

Question 40

What is the change in pressure that allows the foramen ovale to close?

Answer 40

At birth, the infant takes a breath - there is a decreased resistance in pulmonary a/v and the LA pressure increases versus the R atrial pressure makes the foramen ovale closes

Question 41

What process leads to the closure of ductus arteriosus?

Answer 41

Higher levels of O2 from respiration and decrease in prostaglandins due to placental separation lead to closure of ductus arteriosus

Question 42

Which drug aids in closing PDA? What keeps it open?

Answer 42

Close PDA - Indomethacin Keep PDA open - PGE1; PGE2

Question 43

With what disease would you want to keep a PDA open?

Answer 43

Transposition of vessels, Pulm atresia

Question 44

What is the origin of the nucleus pulposus?

Answer 44

notochord