Cardiac embryo

Question 1

Cardiac muscle origin

Answer 1

Splachnic mesoderm

Question 2

Begining of heart formation?

Answer 2

End of week 3

Question 3

Primordial heart starts beating

Answer 3

beginning of week 4

Question 4

Heart ends up in the thoracic cavity because of ___ folding

Answer 4

cranial

Question 5

2 hearts fuse into one because of the _____ folding

Answer 5

lateral

Question 6

the endothelial tube cells that fuse form the

Answer 6

endocardium

Question 7

The embryonic heart begins to beat by day:

Answer 7

22-23

Question 8

Primitive heart is surrounded by

Answer 8

the coleomic cavity, which will form the visceral and parietal layers of the pericardium

Question 9

The primitive heart is surrounded by

Answer 9

coelomic cavity, will form the serous (visceral and parietal) and fibrous pericardium.

Question 10

Fused tubes get thicker and form segments

Answer 10

bulbus cordis, ventricle, atrium and sinus venosus

Question 11

Heart folds on itself, S shaped so,

Answer 11

ventricle move ventrally and right

atrium move dorsally and left

Question 12

On the adult heart there is a portion that is trabeculated and the other smooth, why?

Answer 12

Depending on its “origin” primitive (trabeculated) or from the vessels ( smooth)

Question 13

Answer 13

Question 14

How is the heart attach to the body walls ( first weeks and later weeks)

Answer 14

First weeks by the dorsal mesocardium, later by blood vessels.

Question 15

What is the transverse sinus and where does it originate from

Answer 15

space between pulmonary trunk/aorta and the SVC

Question 16

Week 4 symmetrical veins that enter to the atrium

Answer 16

cardinal, umbilical and vitelline ( most disappear)

Question 17

What is the crista terminalis?

Answer 17

Is the separation of smooth and trabecula on the right atrium.

Question 18

Valves of the inferior vena cava and coronary sinus from on:

Answer 18

The caudal region of the right atrium

Question 19

The left atrium smooth portion is formed by which vessels?

Answer 19

pulmonary veins

Question 20

The atrioventricular septum is formed by:

Answer 20

the thickening of the endocardial cushions.

Question 21

Endocardial cushion cells origin

Answer 21

neural crest cells

Question 22

What is the septum primum

Answer 22

The septum primum grows toward the fusing endocardial cushions from the roof of the primordial atrium, partially dividing the common atrium into right and left halves.

Question 23

What is the ostium/foramen primum?

Answer 23

As the septum primum grows the foramen primum forms as an opening that remains between its edge and the endocardial cushions

This foramen serves as a shunt, enabling oxygenated blood to pass from the right to the left atrium.

The foramen becomes progressively smaller and disappears

Question 24

What is the ostium/foramen secundum

Answer 24

Before the foramen primum disappears, perforations produced by
apoptosis appear in the central part of the septum primum. These perforations form the foramen secundum.

The foramen secundum ensures continued shunting of oxygenated blood from the right to the left atrium.

Question 25

What is the septum secundum?

Answer 25

The septum secundum, thicker, grows from the wall of the right atrium, adjacent to the septum primum.

As it grows it overlaps the foramen secundum.

The septum secundum forms an incomplete partition between the atria; conse-
quently, a foramen ovale(flap-like) forms

Question 26

Why is the foramen ovale important

Answer 26

Before birth, the foramen ovale allows most of the oxygenated blood
entering the right atrium from the IVC to pass into the left atrium.
It also prevents the passage of blood in the opposite direction because the septum primum closes against the relatively rigid septum secundum

Question 27

How does the foramen ovale allow blood flow to bypass from right to left before birth

Answer 27

Because the pressure on the left side is lower than on the right side, after birth it switches and no longer blood can flow

Question 28

Embryonic circulation shunts

Answer 28

ductus venosus, foramen ovale and ductus arteriosus

Question 29

What is the ductus venosus

Answer 29

Shunt for the umbilical vein

Question 30

What is the ductus arteriosus?

Answer 30

Shunt between the pulmonary artery and the aorta.

Ductus arteriosus becomes the ligamentum arteriosum

Question 31

Atrial septum defects (ASD)

Answer 31

Ostium primum defect and ostium secundum defect

Question 32

What is the origin of the AV valves cells?

Answer 32

Neural crest cells, like the endocardial cushions.

Question 33

Outflow of ventricles is formed by

Answer 33

the bulbus cordis and troncus arteriosus, they grow in a spiral way

Question 34

How does the ventricular septum grows?

Answer 34

It grows from the floor of the ventricles, leaving an opening (interventricular foramen), which closes by week 7.

Question 35

Cardiac anomalies

Answer 35

tetralogy of fallot (pulmonary stenosis), aortic stenosis, etc.