11.22 B

Question 1

What are the endocardial tubes?

Answer 1

lines of embryonic heart precursor cells that will give rsie to the primitive heart tube

Question 2

The medial endocardial tubes give rise to what?

Answer 2

the dorsal aortae

Question 3

The lateral endocardial tubes give rise to what?

Answer 3

venous structures

Question 4

Cranial folding on day 20 gives rise to what embryonic heart changes?

Answer 4

• formation of the aortic arch

- fusion of the right and left endocardial tubes

Question 5

Describe the sequence of blood flow through the primitive heart tube.

Answer 5

sinus venosus to atrium to ventricle to bulbus cordis to aortic sac

Question 6

When does the embryonic heart start to beat?

Answer 6

it starts beating on day 22 but with little directionality

Question 7

What is the truncus arteriosus?

Answer 7

the part of the primitive heart tube that will give rise to the ascending aorta and pulmonary trunk

Question 8

What is the sinus venosus?

Answer 8

the primitive heart structure that gives rise to the right atrium and coronary sinus

Question 9

What events give rise to the pericardial sinuses?

Answer 9

folding of the primitive heart tube

Question 10

What is cardiac jelly?

Answer 10

ECM secreted in between myocardium and primitive endothelium of the heart tube

Question 11

The pericardial sac forms from what embryonic cell population?

Answer 11

mesothelial cells

Question 12

From inside out, what are the four layers of the heart tube?

Answer 12

• endocardium (primitive endothelium)
• cardiac jelly (ECM)
• myocardium
• epicardium (visceral pericardium)

Question 13

During folding of the heart tube, the bulbus cordis is displaced in which direction?

Answer 13

inferiorly, ventrally, and to the right side of the body

Question 14

Duringn folding of the heart tube, the sinus venosus is displaced in which direction?

Answer 14

superiorly and posteriorly

Question 15

What is dextrocardia?

Answer 15

improper twisting of the heart tube such that the base of the heart is directed to the right side of the body

Question 16

What is the difference in prognosis between those with dextrocardia and those with situs inversus?

Answer 16

those with just dextrocardia are more likely to have additional heart defects while those with situs inversus only have a slightly increased risk

Question 17

Endocardial cushions form what?

Answer 17

the septum intermedium which separates the atrium from ventricles

Question 18

What is the septum intermedium?

Answer 18

the structure that separates the atrium from the ventricles

Question 19

What is the septum primum?

Answer 19

a crescent-shaped structure that grows down from the superoposterior wall of the atrium to begin forming the left and right atrium

Question 20

What is the ostium primum?

Answer 20

the opening in the septum primum between the left and right atrium

Question 21

What is the ostium secundum?

Answer 21

an opening that forms in the septum primum before closure of the ostium primum to keep the right and left atria connected

Question 22

Endocardial cushion cells are derived from what?

Answer 22

neural crest cells

Question 23

Why do individuals that suffer from craniofacial defects often also have congenital heart defects?

Answer 23

because both are due to neural crest cell defects

Question 24

Neural crest cell deficits often disrupt formation of what heart structures?

Answer 24

endocardial cushions

Question 25

Endocarial cushion defects can lead to what heart defects?

Answer 25

- atrial and ventricular septal defects - atrioventricular defects - transposition of the great vessels

Question 26

What is an atrioventricular canal?

Answer 26

an atrioventricular septal defect (aka an endocardial cushion defect)

Question 27

People with Down Syndrome commonly have what heart defect?

Answer 27

an atrioventricular septal defect

Question 28

How does an atrioventricular septal defect often present?

Answer 28

- tachypnea - poor feeding (need to breath instead) - growth retardation - typically identified around 6 weeks - cyanosis sometimes seen

Question 29

What is the foramen ovale?

Answer 29

an opening in the septum secundum

Question 30

The foramen ovale and ostium secundum allow for what throughout embryonic development?

Answer 30

blood flow from the right to left atrium

Question 31

A one way intraatrial valve is formed by what structures during embryonic development?

Answer 31

the septum secundum (an its foramen ovale) and the ostium secundum in the septum primum

Question 32

In adults, an atrial septal defect allows flow of blood in which direction?

Answer 32

left to right atrium

Question 33

What symptoms are present with an atrial septal defect?

Answer 33

- often very few - shortness of breath - easy fatigue - poor growth

Question 34

What murmur most often accompanies an atrial septal defect?

Answer 34

an S2 split thanks to delayed pulmonic valve closure due to more blood passing through the right side of the heart

Question 35

How is an atrial septal defect often treated?

Answer 35

by placing a septal occluder and without open heart surgery

Question 36

How does a secundum atrial septal defect arise?

Answer 36

poor growth of the septum secundum leaves overlap between the foramen ovale and the ostium secundum

Question 37

How does a patent foramen ovale develop?

Answer 37

from failure of the two atrial septa to fuse

Question 38

A patent foramen ovale doesn't often lead to problems because...

Answer 38

as long as pressure in the left atrium is higher than that of the right, the foramen ovale "valve" is kept shut

Question 39

A patient presents with fixed splitting of the second heart sound, an ejection murmur, right ventricular conduction delay, and enlargement of the right heart. You suspect what?

Answer 39

an atrial septal defect

Question 40

Patent foramen ovale are most problematic because they can lead to what?

Answer 40

paradoxical embolization

Question 41

What is a paradoxical embolization?

Answer 41

an embolus arising in the systemic venous system or right atrium crosses the patent foramen ovale and enters systemic arterial circulation

Question 42

The smooth walls of the atria are derived from what heart tube structure?

Answer 42

the sinus venosus

Question 43

What is the interventricular septum?

Answer 43

the divider between the two ventricles

Question 44

What is the interventricular foramen?

Answer 44

the hole between the two ventricles left by the halted growth of the muscular interventricular septum

Question 45

The interventricular septum is composed of what two portions?

Answer 45

the muscular and the membranous

Question 46

How are ventricular septal defects treated?

Answer 46

most close on their own by age 5

Question 47

What is the truncus arteriosus?

Answer 47

the structure that will give rise to both the aorta and the pulmonic trunk

Question 48

What are conotruncal swellings?

Answer 48

ridges that develop in the truncus arteriosus wall that will divide it into the aorta and pulmonic trunk

Question 49

The conotruncal swellings of the truncus arteriosus are derived from what cell population?

Answer 49

neural crest cells

Question 50

Failure to form the septum of the truncus arteriosus outflow tract leads to what problems?

Answer 50

- transposition of the great arteries - pulmonary stenosis - persistent truncus arteriosus - tetraology of Fallot

Question 51

How does transposition of the great vessels present?

Answer 51

with cyanosis

Question 52

Infants with transposition of the great vessels can live longer without treatment if what occurs?

Answer 52

persistent or patent foramen ovale or patent ductus arteriosus

Question 53

What is the ductus arteriosus?

Answer 53

a vessel connecting the pulmonary artery to the proximal descending aorta

Question 54

What is persistent truncus arteriosus?

Answer 54

failure of the truncus arteriosus to divide and give rise to the aorta and pulmonary trunk

Question 55

Persistent truncus arteriosus presents with what?

Answer 55

cyanosis and death unless corrected

Question 56

What is the tetraology of Fallot?

Answer 56

- ventricular septal defect - pulmonary stenosis - aorta that overrides both ventricles - hypertrophy of right ventricle

Question 57

When is tetraology of Fallot typically detected?

Answer 57

months to years after birth

Question 58

How does tetraology often present?

Answer 58

sudden incidence of cyanosis with hyperpnea between 2 mo and 2 yrs old

Question 59

The severity of Tetraology of Fallot is largely dictated by what factor?

Answer 59

the degree of pulmonary stenosis

Question 60

How does pulmonary stenosis present?

Answer 60

- usually asymptomatic unless the individual is exercising | - if more severe, there may be a an S2 split

Question 61

S2 splitting is most often indicative of what?

Answer 61

pulmonary stenosis

Question 62

Rheumatic disease can sometimes lead to what heart defect?

Answer 62

aortic valve stenosis

Question 63

Aortic valvular stenosis leads to what secondary problem?

Answer 63

enlargement of the aortic arch

Question 64

How do chordea tendonae form?

Answer 64

through programmed cell death

Question 65

What is the ligamentum arteriosum?

Answer 65

the remnants of the ductus arteriosus

Question 66

What is special about ductus arteriosus smooth muscle?

Answer 66

it is induced to contrcat upon exposure to oxygen

Question 67

Coarctation of the aorta is due to what?

Answer 67

malpositioning of the ductus arteriosus smooth muscle

Question 68

Hypertension in the upper extremities and hypotension in the lower is the hallmark of what defect?

Answer 68

coarctation of the heart

Question 69

How does coarctation of the heart often present?

Answer 69

- upper extremity hypertension and lower extremity hypotension - left ventricular hypertrophy - pain upon exercise in lower limbs

Question 70

Notching of the lower surface of the ribs is indicative of what heart defect?

Answer 70

coarctation of the aorta

Question 71

The third aortic arch often gives rise to what adult structures?

Answer 71

internal carotid artery

Question 72

The fourth aortic arch often gives rise to what adult structures?

Answer 72

the right subclavian artery and arch of the aorta

Question 73

The sixth aortic arch often gives rise to what adult structures?

Answer 73

the pulmonary arteries and ligamentous arteriosus

Question 74

What is the embryonic importance of the ductus arteriosus?

Answer 74

connect the pulmonary arteries to the arch of the aorta thus bypassing the fetal lungs

Question 75

The aortic arches are surrounded by what nerves?

Answer 75

the left and right recurrent laryngeal nerve

Question 76

Name the three arteries that come off the aortic arch?

Answer 76

- brachiocephalic - left common carotid - left subclavian

Question 77

Aortic/branchial arch anomalies often lead to what?

Answer 77

disrupted breathing and problems swallowing

Question 78

What are the vitelline veins?

Answer 78

those serving the yolk sac

Question 79

What are the umbilical veins?

Answer 79

those serving the placenta

Question 80

What are the cardinal veins?

Answer 80

those serving the embryo

Question 81

What are the three pairs of veins returning blood to the embryonic heart at the sinus venosus?

Answer 81

- vitelline - umbilical - cardinal

Question 82

How does venous return shift during development?

Answer 82

initially, cardinal veins are bilateral with return of teh blood to both horns of teh sinus venosus, but then there is a shift to the right

Question 83

The superior vena cava is derived from what?

Answer 83

the right anterior cardinal vein

Question 84

The inferior vena cava is derived from what embryonic structure?

Answer 84

the inferior vitelline vein

Question 85

The right horn of the sinus venosus becomes what?

Answer 85

part of the right atrium

Question 86

The left horn of the sinus venosus becomes what?

Answer 86

the coronary sinus

Question 87

The portal vein in liver develops from what?

Answer 87

vitelline veins

Question 88

What is the ductus venosus?

Answer 88

a channel through the liver that allows blood from the left umbilical vein directly through the liver to the inferior vena cava

Question 89

What happens to the left umbicial vein in the liver?

Answer 89

- at first it enlarges to become the ductus venosus | - then it involutes after birth to form the ligamentum venosum

Question 90

The ductus venosus is derived from what embryonic vein?

Answer 90

the left umbilical vein

Question 91

Prior to birth, what are the two shunts that allow right to left blood flow to bypass the fetal lung?

Answer 91

- foramen ovale | - ductus arteriosus

Question 92

What role does bradykinin play in the cardiovascular system immediately at birth?

Answer 92

it serves to decrease the vascular resistance within the lung as the oxygen source changes

Question 93

What happens to right arterial pressure just after birth?

Answer 93

it declines as umbilical blood flow is lost

Question 94

What molecule reduces the vascular resistance of the lungs just after birth?

Answer 94

bradykinin

Question 95

What is indomethican?

Answer 95

a prostaglandin inhibitor given to speed up the closure of the patent ductus arteriosus

Question 96

Why would transposition of the great arteries be treated with prostaglandin?

Answer 96

prostaglandin will slow closure of the ductus arteriosus allowing some oxygenated blood from the right ventricle to reach the systemic arteries

Question 97

A machine like murmur present during systole and diastole and cyanosis of just the toes is indicative of what?

Answer 97

patent ductus arteriosus