11.22 B Flashcards

1
Q

What are the endocardial tubes?

A

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

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2
Q

The medial endocardial tubes give rise to what?

A

the dorsal aortae

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3
Q

The lateral endocardial tubes give rise to what?

A

venous structures

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4
Q

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

A
  • formation of the aortic arch

- fusion of the right and left endocardial tubes

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5
Q

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

A

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

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6
Q

When does the embryonic heart start to beat?

A

it starts beating on day 22 but with little directionality

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7
Q

What is the truncus arteriosus?

A

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

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8
Q

What is the sinus venosus?

A

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

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9
Q

What events give rise to the pericardial sinuses?

A

folding of the primitive heart tube

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10
Q

What is cardiac jelly?

A

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

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11
Q

The pericardial sac forms from what embryonic cell population?

A

mesothelial cells

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12
Q

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

A
  • endocardium (primitive endothelium)
  • cardiac jelly (ECM)
  • myocardium
  • epicardium (visceral pericardium)
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13
Q

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

A

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

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14
Q

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

A

superiorly and posteriorly

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15
Q

What is dextrocardia?

A

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

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16
Q

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

A

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

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17
Q

Endocardial cushions form what?

A

the septum intermedium which separates the atrium from ventricles

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18
Q

What is the septum intermedium?

A

the structure that separates the atrium from the ventricles

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19
Q

What is the septum primum?

A

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

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20
Q

What is the ostium primum?

A

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

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21
Q

What is the ostium secundum?

A

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

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22
Q

Endocardial cushion cells are derived from what?

A

neural crest cells

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23
Q

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

A

because both are due to neural crest cell defects

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24
Q

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

A

endocardial cushions

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25
Q

Endocarial cushion defects can lead to what heart defects?

A
  • atrial and ventricular septal defects
  • atrioventricular defects
  • transposition of the great vessels
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26
Q

What is an atrioventricular canal?

A

an atrioventricular septal defect (aka an endocardial cushion defect)

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27
Q

People with Down Syndrome commonly have what heart defect?

A

an atrioventricular septal defect

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28
Q

How does an atrioventricular septal defect often present?

A
  • tachypnea
  • poor feeding (need to breath instead)
  • growth retardation
  • typically identified around 6 weeks
  • cyanosis sometimes seen
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29
Q

What is the foramen ovale?

A

an opening in the septum secundum

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30
Q

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

A

blood flow from the right to left atrium

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31
Q

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

A

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

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32
Q

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

A

left to right atrium

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33
Q

What symptoms are present with an atrial septal defect?

A
  • often very few
  • shortness of breath
  • easy fatigue
  • poor growth
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34
Q

What murmur most often accompanies an atrial septal defect?

A

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

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35
Q

How is an atrial septal defect often treated?

A

by placing a septal occluder and without open heart surgery

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36
Q

How does a secundum atrial septal defect arise?

A

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

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37
Q

How does a patent foramen ovale develop?

A

from failure of the two atrial septa to fuse

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38
Q

A patent foramen ovale doesn’t often lead to problems because…

A

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

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39
Q

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?

A

an atrial septal defect

40
Q

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

A

paradoxical embolization

41
Q

What is a paradoxical embolization?

A

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

42
Q

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

A

the sinus venosus

43
Q

What is the interventricular septum?

A

the divider between the two ventricles

44
Q

What is the interventricular foramen?

A

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

45
Q

The interventricular septum is composed of what two portions?

A

the muscular and the membranous

46
Q

How are ventricular septal defects treated?

A

most close on their own by age 5

47
Q

What is the truncus arteriosus?

A

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

48
Q

What are conotruncal swellings?

A

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

49
Q

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

A

neural crest cells

50
Q

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

A
  • transposition of the great arteries
  • pulmonary stenosis
  • persistent truncus arteriosus
  • tetraology of Fallot
51
Q

How does transposition of the great vessels present?

A

with cyanosis

52
Q

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

A

persistent or patent foramen ovale or patent ductus arteriosus

53
Q

What is the ductus arteriosus?

A

a vessel connecting the pulmonary artery to the proximal descending aorta

54
Q

What is persistent truncus arteriosus?

A

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

55
Q

Persistent truncus arteriosus presents with what?

A

cyanosis and death unless corrected

56
Q

What is the tetraology of Fallot?

A
  • ventricular septal defect
  • pulmonary stenosis
  • aorta that overrides both ventricles
  • hypertrophy of right ventricle
57
Q

When is tetraology of Fallot typically detected?

A

months to years after birth

58
Q

How does tetraology often present?

A

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

59
Q

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

A

the degree of pulmonary stenosis

60
Q

How does pulmonary stenosis present?

A
  • usually asymptomatic unless the individual is exercising

- if more severe, there may be a an S2 split

61
Q

S2 splitting is most often indicative of what?

A

pulmonary stenosis

62
Q

Rheumatic disease can sometimes lead to what heart defect?

A

aortic valve stenosis

63
Q

Aortic valvular stenosis leads to what secondary problem?

A

enlargement of the aortic arch

64
Q

How do chordea tendonae form?

A

through programmed cell death

65
Q

What is the ligamentum arteriosum?

A

the remnants of the ductus arteriosus

66
Q

What is special about ductus arteriosus smooth muscle?

A

it is induced to contrcat upon exposure to oxygen

67
Q

Coarctation of the aorta is due to what?

A

malpositioning of the ductus arteriosus smooth muscle

68
Q

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

A

coarctation of the heart

69
Q

How does coarctation of the heart often present?

A
  • upper extremity hypertension and lower extremity hypotension
  • left ventricular hypertrophy
  • pain upon exercise in lower limbs
70
Q

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

A

coarctation of the aorta

71
Q

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

A

internal carotid artery

72
Q

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

A

the right subclavian artery and arch of the aorta

73
Q

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

A

the pulmonary arteries and ligamentous arteriosus

74
Q

What is the embryonic importance of the ductus arteriosus?

A

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

75
Q

The aortic arches are surrounded by what nerves?

A

the left and right recurrent laryngeal nerve

76
Q

Name the three arteries that come off the aortic arch?

A
  • brachiocephalic
  • left common carotid
  • left subclavian
77
Q

Aortic/branchial arch anomalies often lead to what?

A

disrupted breathing and problems swallowing

78
Q

What are the vitelline veins?

A

those serving the yolk sac

79
Q

What are the umbilical veins?

A

those serving the placenta

80
Q

What are the cardinal veins?

A

those serving the embryo

81
Q

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

A
  • vitelline
  • umbilical
  • cardinal
82
Q

How does venous return shift during development?

A

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

83
Q

The superior vena cava is derived from what?

A

the right anterior cardinal vein

84
Q

The inferior vena cava is derived from what embryonic structure?

A

the inferior vitelline vein

85
Q

The right horn of the sinus venosus becomes what?

A

part of the right atrium

86
Q

The left horn of the sinus venosus becomes what?

A

the coronary sinus

87
Q

The portal vein in liver develops from what?

A

vitelline veins

88
Q

What is the ductus venosus?

A

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

89
Q

What happens to the left umbicial vein in the liver?

A
  • at first it enlarges to become the ductus venosus

- then it involutes after birth to form the ligamentum venosum

90
Q

The ductus venosus is derived from what embryonic vein?

A

the left umbilical vein

91
Q

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

A
  • foramen ovale

- ductus arteriosus

92
Q

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

A

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

93
Q

What happens to right arterial pressure just after birth?

A

it declines as umbilical blood flow is lost

94
Q

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

A

bradykinin

95
Q

What is indomethican?

A

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

96
Q

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

A

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

97
Q

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

A

patent ductus arteriosus