Basic Cardiac Embryology - Module 4

3-7 weeks

What gestational age is the heart formed

True

T/F: the heart is the 1st organ to develop

Cardiogenic area

What first appears in week 3, marking the start of heart formation

Cardiogenic area

What does this image represent

Pericardial cavity

Where does the heart lie

2 tubes

What does the heart start off as

Fuse and twist

What must the 2 heart tubes to in order to from the adult heart

Heart tube fusion

What does this image show

Heart tube begins to fold and twist

What does this image show

First aortic arch

What is 1

Bulbus cordis

What is 2

Ventricle

What is 3

Atrium

What is 4

Unidirectional

Describe the blood flow in the fetal heart tube when it first forms

Ascending ao and pulmonary trunk

What does truncus arteriosus develop into

Infundibulum and LVOT

What does bulbus cordis develop into

LV

What does primitive ventricle develop into

Atrium

What does primitive atrium develop into

Coronary sinus

What does sinus venosus develop into

Heart now a more complex structure with two atria and two ventricles

What does looping of the heart transform the single heart tube into

Rightwards

What is normal looping

Leftwards

What is ABNORMAL looping

Top twists to the RT of fetus

Describe how a normal rightwards looping occurs

Truncus arteriosus (asc ao + pulm trunk)

What is 1

Bulbus cordis (infundibulum + LVOT)

What is 2

Primitive ventricle (LV/RV?)

What is 3

Primitive atrium (atrium)

What is 4

Sinus venosus (coronary sinus)

What is 6

Interventricular secular (IVS)

What is 7

Atrioventricular sulcus (AVS)

What is 8

LT transposition of the great arteries

What does leftwards folding result in

LT transposition of the great arteries

What does L-TGA stand for

Separates

What does septum mean

Hole

What does foramen mean

Truncus arteriosus

What is 1

Ventricle

What is 2

Atrium

What is 3

First and second arches

What is 4

Truncus arteriosus

What is 5

Bulbus cordis

What is 6

Sinus venosus

What is 7

Common cardinal vein

What is 8

Umbilical vein

What is 9

1st (think primary)

What does primum means

2nd

What does secundum mean

Normal rightward looping of the heart tube

What does this image show

Primitive atrium

What does the yellow circle indicate

Septum primum

What is stage 1 of atrial septal formation

Divides atrium into RT and LT

What does septum primum do

Extends down from the roof of the common atrium toward endocardial cushion

How does the septum primum develop

No

Does septum primum fully connect to the endocardial cushions and close off the IAS

Foramen primum

What is the gap between the septum primum and endocardial cushions

Primum ASD

What ASD does the foramen primum turn into if this gap does not close off after baby is born

Septum primum

What is 1

Foramen primum

What is 2

Endocardial cushions

What is 3

Septum primum grows toward endocardial cusions

What is step 2 of atrial septal formation

Foramen primum closes

Besides growing inferiorly towards the endocardial cushions, what else does the stage 2 involve (what does this growth result in)

Perforations

What appears in the upper portion of the septum primum after its inferior growth in stage 2

Foramen secundum

What does these perforations result in

Secundum ASD

What ASD would these perforations lead to if it doesn't close up properly

Septum primum growth

What is 1

Foramen secundum

What is 2

Septum secundum

What is the 3rd stage of atrial septal formation

Adjacent and to the right of septum primum (superior atrium)

How does septum secundum grow

Foramen secundum

What does septum secundum partially overlap

Foramen ovale

What does septum secundum creat by partially ovale flapping foramen secundum

PFO

What ASD does foramen ovale form if not closed fully

Septum secundum

What is 1

Foramen ovale

What is 2

Foramen ovale

What is stage 4 of atrial septal formation

Upper septum primum

What disappears in stage 4 of atrial septal formation

Valve of foramen ovale

What does the lower part of septum primum become (once the upper part disappears

RA>LA pressure

What keeps the foramen ovale open during gestation

Septum secundum grows superior from the AV cushions

What happens to septum secundum as well during stage 4

Original growth of septum secundum

What is 1 pointing to

New growth of septum secundum

What is 2 pointing to

Disappearance of upper septum primum

What is 3 pointing to

Valve of foramen ovale (lower part of septum primum)

What is 4 pointing to

Foramen ovale

What is 5 pointing to

Increase in systemic vascular resistance and decrease in RA pressure results in the LA pressure rising higher than the RA pressure

Describe the changes of pressure at brith in te heart

Pushes the valve of foramen ovale against the septum secundum, closing the foramen ovale hole

What does this increase in LA pressure at birth result in

Fuse

Over time, the valve of foramen ovale and septum secundum should _____________

25%

What % of people is it estimated that the flaps of foramen ovale don't fully fuse together

Ostium primum ASD

What is 1

PFO (fossa ovalis)

What is 2

Ostium secundum ASD

What is 3

Sinus venous ASD (superior and inferior)

What is 4

Fossa ovalis

What is another term for a PFO

Patent foramen ovale

What does PFO stand for

Primitive ventricle/bulbus cordis

What does the yellow circle indicate

Atrioventicular

What does AVC stand for

Bulbus cordis

What does BC stand for

Primitive ventricle

What does PV stand for

Trabecular IVS

What is stage 1 of ventricle septal formation

Part of the RV

What does the bulbus cordis become in stage 1

LV and the rest of the RV

What does the primitive ventricle become in stage 1

Trabecular IVS (muscular)

What part of the IVS grows in stage 1

Grows from apex to base but stops part way

Describe how the trabecular IVS grows in stage 1

Allows blood flow from both ventricles to exit the truncus arteriosus through the interventricular foramen

Why does the trabecular IVS stop partway while growing in stage 1