10.24.16 Embryology of the Heart

Question 1

The cardiovascular system begins to develop at the end of the ___.

Answer 1

3rd week

Question 2

The primordial heart starts to beat at the beginning of the ___.

Answer 2

4th week

Question 3

What develops into two heart tubes that join to form the primordial vascular system?

Answer 3

Proliferating mesenchymal cells derived from the splanchnic mesoderm

Question 4

What are the three layers of heart cells?

Answer 4

1. Endocardium
2. Myocardium
3. Epicardium

Question 5

What are the 5 chambers of the heart tube (cranio-caudal order)?

Answer 5

1. Truncus arteriosus
2. Bulbus cordis
3. Primitive ventricle
4. Primitive atrium
5. Sinus venosus

Question 6

Which chamber of the heart contributes to the pulmonary trunk and aorta?

Answer 6

Truncus arteriosus

Question 7

Which chamber of the heart contributes to the right and left auricles?

Answer 7

Primitive atrium

Question 8

Which chamber of the heart contributes to the coronary sinus and part of the right atrium?

Answer 8

Sinus venosus

Question 9

Which chamber of the heart contributes to the smooth part of the right and left ventricles?

Answer 9

Bulbis cordis

Question 10

Which chamber of the heart contributes to the rough part of the the right and left ventricles?

Answer 10

Primitive ventricle

Question 11

What cause the “S” shaped lopping of the heart?

Answer 11

As the heart grows, it bends to the right, which moves the primitive atrium and ventricle into roughly correct anatomical position

Question 12

The right horn of the sinus venosus gives the ___.

Answer 12

Sinus venarum (smooth part of right atrium)

Question 13

The left horn of the sinus venosus gives the ___.

Answer 13

Coronary sinus

Question 14

How is the atrioventricular canal formed?

Answer 14

Two endocardial cushions grow and fuse to form the AV septum. This divides the canal into right AV (tricuspid) and left AV (bicuspid) canals.

Question 15

What is the crescent membrane that grows down from the wall of the atrium toward the endocardial cushions?

Answer 15

Septum primum

Question 16

What is the opening that allows blood flow from the right atrium to the left atrium?

Answer 16

Ostium primum

Question 17

What is the new opening that appears by perforation of the septum primum?

Answer 17

Ostium secundum

Question 18

What membrane grows down from the atrium and covers (but does not seal) the ostium secundum, leaving an opening which is a valve-like path for the blood from the right to the left atrium?

Answer 18

Septum secundum

Question 19

After birth, the septum secundum closes, leaving behind the ___.

Answer 19

Fossa ovalis

Question 20

The ___ becomes divided into two halves by interventricualr septum which is formed of two parts.

Answer 20

Primitive ventricle

Question 21

The spiral orientation of the bulbar and truncal ridges results in the formation of a spiral ___ which provides continuity of the aorta with the left ventricle and the pulmonary trunk with the right ventricle.

Answer 21

Aorticopulmonary septum

Question 22

As the pharyngeal arches form during the 4th and 5th weeks, they are penetrated by ___ that arise from the aortic sac.

Answer 22

Pharyngeal arteries

Question 23

___ pairs of aortic arches connect the dorsal aorta with the ventral aortic sac.

Answer 23

Six

Question 24

Which aortic arch completely disappears?

Answer 24

5th

Question 25

What is the derivative of the 1st aortic arch?

Answer 25

Maxillary artieres

Question 26

What is the derivative of the 2nd aortic arch?

Answer 26

Hyoid and stapedial arteries

Question 27

What is the derivative of the 3rd aortic arch?

Answer 27

Common carotid and first part of the internal carotid arteries

Question 28

What is the derivative of the 4th aortic arch (left side)?

Answer 28

Arch of the aorta from the left common carotid to the left subclavian arteries

Question 29

What is the derivative of the 4th aortic arch (right side)?

Answer 29

Right subclavian artery (proximal portion)

Question 30

What is the derivative of the 6th aortic arch (left side)?

Answer 30

Left pulmonary artery and ductus arteriosus

Question 31

What is the derivative of the 6th aortic arch (right side)?

Answer 31

Right pulmonary artery

Question 32

The fetal cardiovascular system is structurally designed so that blood is oxygenated in the ___ and most of it bypasses the lungs.

Answer 32

Placenta

Question 33

Failure of the postnatal circulatory changes to occur at birth results in two of the most common congenital anomilies of the heart - what are they?

Answer 33

Patent foramen ovale and patent ductus arteriosus (PDA)

Question 34

PDA is the most common congenital cardiac malformation associated with ___.

Answer 34

Rubella infection of the mother

Question 35

What type of defect is patent foramen ovale?

Answer 35

Atrial septal defect (ASD)

Question 36

What is the most common congenital heart defect?

Answer 36

Ventricular septal defects (VSD) - usually in the membranous part

Question 37

What are the three abrnomal divisions of the truncus arteriosus?

Answer 37

1. Persistent truncus arteriosus 2. Transposition of the great vessels 3. Fallot's tetralogy

Question 38

What is dextrocardia?

Answer 38

Right-sided heart

Question 39

What is the most common cyanotic heart lesion?

Answer 39

Fallot's tetralogy

Question 40

What are the four features of Fallot's tetralogy?

Answer 40

1. Overriding aorta 2. Pulmonary stenosis 3. VSD 4. Hypertrophy of right ventricle