Development Of The Heart

Question 1

Which germ layer does the cardiovascular system develop from

Answer 1

Mesoderm

Question 2

What does the heart develop from

Answer 2

Cardiogenic mesoderm

Question 3

What do angiogenic cell clusters in the cardiogenic mesoderm coalesce to form

Answer 3

Left and right endocardial tubes

Question 4

What causes the endocardia tubes to fuse into the primitive heart tube

Answer 4

Lateral folding of embryo

Question 5

What does the truncus arteriosus become

Answer 5

Proximal aorta and pulmonary artery

Question 6

What does the bulbous cordis become

Answer 6

Ventricular outflow tracts and right ventricle

Question 7

What does the primitive ventricle become

Answer 7

Left ventricle

Question 8

What does the primitive atria become

Answer 8

Left and right atria

Question 9

What does the sinus venosus become

Answer 9

Smooth part of right atrium and coronary sinus

Question 10

What parts of the heart are present at 21 days gestation

Answer 10

Truncus arteriosus
Bulbous cordis
Primitive ventricle
Primitive atria
Sinus venosus

Question 11

Why does the primitive heart tube fold as it lengthens

Answer 11

Length limited by pericardium

Question 12

What causes the chambers and vessels of the heart to align during gestation

Answer 12

Folding of primitive heart tube

Question 13

When does the primitive heart tube fold

Answer 13

Days 23 - 28

Question 14

What connects the atrium and ventricle at 35 days

Answer 14

Atrioventricular canal

Question 15

What are the endocardial cushions and when do they form

Answer 15

2 swellings of mesenchymal tissue from walls of atrioventricular canal
28 days

Question 16

What does the septum of the atrioventricular canal form from

Answer 16

Endocardial cushions

Question 17

Where does the foramen ovale shunt blood from and too

Answer 17

Taught atrium to left atrium

Question 18

Why does the foramen ovale fuse after birth

Answer 18

Higher pressure in left atrium than right atrium

Question 19

Are atrial septal defects more common in males or females

Answer 19

Females

Question 20

2 parts of atrial septum

Answer 20

Septum premium
Septum secondum

Question 21

When does the muscular interventricular septum develop

Answer 21

End of 4th week

Question 22

Where does the muscular interventricular septum grow from and towards

Answer 22

From floor of primordial ventricle
Towards membranous interventricular septum

Question 23

What does the membranous interventricular septum form from

Answer 23

Endocardial cushions

Question 24

What is the most common type of cardiac defect

Answer 24

Ventricular septal defect

Question 25

What proportion of ventricular septal defects are in the membranous septum

Answer 25

90%

Question 26

Where and when do the truncoconal swellings form

Answer 26

Truncus arteriosus 5th wk

Question 27

Why do the truncoconal swellings grow towards each other in a spiral

Answer 27

So aorta connects to LV and pulmonary ventricle to RV

Question 28

What does the ductus venodud shunt blood between

Answer 28

Umbilical vein to IVC

Question 29

What does the foramen ovale shunt blood between

Answer 29

RA to LA

Question 30

What does the ductus arteriosus shunt blood between

Answer 30

Pulmonary trunk to ascending aorta

Question 31

What structure allows foetal blood to bypass the liver

Answer 31

Ductus venosus

Question 32

What structure allows foetal blood to bypass the pulmonary circulation

Answer 32

Foramen ovale

Question 33

What structure allows foetal blood to bypass the lungs

Answer 33

Ductus arteriosus - Pulmonary trunk to ascending aorta

Question 34

What does the ductus venosus fibrosis to form

Answer 34

Ligamentum venosus/teres

Question 35

What does the foramen ovale close to form

Answer 35

Fossa ovalis

Question 36

What does the ductus arteriosus fibrose to form

Answer 36

Ligamentum arteriosum

Question 37

Acyanotic congenital heart disease

Answer 37

Group of cardiac diseases with a left to right shunt or left heart abnormality which do not result in cyanosis

Question 38

Patent ductus arteriosus

Answer 38

Ductus arteriosus does not close postnatally

Question 39

What does a patent ductus arteriosus increase risk for

Answer 39

Bacterial endocarditis

Question 40

Patent ductus arteriosus treatment

Answer 40

Prostaglandin inhibitor - eg ibuprofen Surgical closure with clip - If not closed by 3 months

Question 41

Coarctation of the aorta

Answer 41

Constriction of aorta

Question 42

What is the difference between pre ductal and post ductal coarctation of the aorta

Answer 42

Pre ductal occurs above ductus arteriosus post ductal below ductus arteriosus

Question 43

What allows blood flow in pre ductal aortic coarctation

Answer 43

Ductus arteriosus persists

Question 44

What allows blood flow in post ductal coarctation of the aorta

Answer 44

Collateral circulations establish

Question 45

How is blood pressure affected by coarctation of the aorta

Answer 45

High bp before coarctation Low bp after coarctation

Question 46

Cyanosis heart lesions

Answer 46

Group of cardiac diseases which allow deoxygenated blood to bypass lungs and enter systemic circulation causing cyanosis

Question 47

What defects comprise tetralogy of fallot

Answer 47

Ventricular septal defect Overriding aorta Pulmonary stenosis Right ventricular hypertrophy

Question 48

Persistent truncus arteriosus

Answer 48

Single truncus arises from heart supplying both aorta and pulmonary artery, large VSD below truncus valve allows blood in LV and RV to mix

Question 49

Features of persistent truncus arteriosus

Answer 49

Variable degree of cyanosis Presents with progressive heart failure

Question 50

Transposition of the great ventricles

Answer 50

Aorta and pulmonary arteries switched

Question 51

What causes transposition of the great vessels

Answer 51

Conotruncal septum runs straight down instead of spiralling

Question 52

What is transposition of the great vessels usually accompanied by

Answer 52

Open ductus arteriosus

Question 53

Transposition of great vessels treatment

Answer 53

Immediate surgical catheterisation of fossa ovalis to increase mixing of pulmonary and systemic blood Further surgery at later date

Question 54

Acyanotic heart lesion examples

Answer 54

Atrial septal defects Ventricular septal defects Patent ductus arteriosus Coarctation of the aorta

Question 55

Cyanosis heart lesion examples

Answer 55

Tetralogy of fallot Transposition of the great vessels Patent truncus arteriosus