embryology of the cvs Flashcards
(90 cards)
1
Q
what are the four stages of heart development?
A
primitive heart tube
heart looping
atrial and ventricular septation
outflow tract septation
2
Q
what forms the circulatory system in the 3rd week
A
lateral plate splanchnic mesoderm
3
Q
what forms two primitive heart tubes?
A
Angiogenic cell islands collect in
the lateral plate splanchnic mesoderm, move towards the midline and coalesce
4
Q
whats the first major system to function in the embryo?
A
cvs
5
Q
when does the primordial heart start to function?
A
4th week
6
Q
where do blood vessels start to appear?
A
wall of yolk sac, allantois, connecting stalk and chorion
7
Q
what are angioblastic cords?
A
paired endothelial strands
8
Q
when does the angioblastic cords form?
A
3rd week
9
Q
what canalises to form heart tubes?
A
angioblastic cords
10
Q
what forms primordial cvs?
A
Tubular heart joins blood vessels in other areas
11
Q
what is the pericardium derived from?
A
intra-embryonic coelom
12
Q
whats the visceral layer of serous pericardium derived from?
A
splanchnic mesoderm
13
Q
what are the terms in a fused primitive heart tube
A
truncus arteriosus bulbus cordis ventrical atrium sinus venosus
14
Q
how many horns does sinus venosus have?
A
2
15
Q
how does each horn of sinus venosus get venous blood?
A
Each horn gets venous blood from:
yolk sac (=vitelline v.)
placenta (=umbilical v.)
body of the embryo (=common cardinal v.)
16
Q
where does aortic arch arise from?
A
aortic sac
17
Q
where does the aortic arch terminate?
A
dorsal aorta
18
Q
what forms the bulboventricular loop?
A
Bulbus cordis and ventricle
19
Q
what way does the heart loop to?
A
left
20
Q
what is dextrocardia?
A
when heart loops to right side of body
21
Q
whats the function of the Endocardial cushion formation
A
separates right atrium + ventricle from
left atrium +ventricle to form L&R AV canals
22
Q
whats the funtion of the Septum formation
A
separates right atrium from left atrium
+ right ventricle from left ventricle
23
Q
when does the partitioning of primitive atrium into left and right atria start?
A
end of weeek 4
24
Q
what are the two septum and two foramina developings during the partition?
A
) Septum primum & foramen primum
2) Septum secundum & foramen secundum
25
what is the septum primum?
the sickle shaped crest that grows from roof of atrium.
| this growth generates foramen primum
26
where is the foramen secundum formed?
upper end of the septum primum
27
where does the septum secundum fold on to?
) forms on the right of septum primum.
28
where does the septum scandium grow down to
grows down and overlaps the foramen secundum
29
where does foramen secundum open in ?
septum primum
30
where doesforamen ovule open in ?
septum secundum
31
whats the role of oval foramen before birth?
Allows most of the blood to pass from the right atrium to the left atrium (non functioning lung)
Prevents the passage of blood in the opposite direction
32
whats the role of oval foramen after birth?
Normally closes (increased pulmonary blood flow and shift of pressure to the left atrium)
Septum primum (= valve of oval foramen) fuses with the septum secundum
Oval fossa (fossa ovalis) of adult heart is a remnant of foetal oval foramen
Non closure results in Atrial Septal Defect (ASD) – “Hole in the heart”
33
what are the four types of atrial septal defects?
Foramen secundum defect
Endocardial cushion defect with foramen primum defect
Sinus venosus defect
Common atrium
The first two types are more common
34
which gender is more likely to get ASD
females
35
what is the opening called in muscular ventricular septum?
interventricular foramen
36
what fuses to form membranous inter ventricular septum?
Bottom of spiral aorticopulmonary septum fuses with muscular ventricular septum
37
what divides the bulbis cordis and truncus arteriosus
aorticopulmonary septum
38
whats the most common congenital heart disease?
Ventricular Septal Defect (VSD)
39
what gender is Ventricular Septal Defect (VSD) more common?
males
40
when does the pacemaker develop?
week 5
41
wheres the adult location of the pacemaker (SA node)
High in the right atrium near the entrance of the SVC
42
what does the aortic sac develop into?
aortic arches
43
what does the bulbus cordis develop into?
right ventricle
| parts of the outflow tracts
44
what does the primitive ventricle develop into?
left ventricle
45
what does the primitive atrium develop into?
parts of right and left atria
46
what does the sinus venosus develop into?
superior vena cava
| right atrium
47
what are the reasons for congenital heart disease?
Rubella infection in pregnancy (PDA)
Maternal alcohol abuse (septal defects)
Maternal drug treatment and radiation
Genetic - 8%
Chromosomal – 2% (Down’s and Turner’s syndrome)
48
what is the cause of transposition of great vessels?
) Failure of aorticopulmonary septum to take a spiral course
- 2) Defective migration of neural crest cells
Common cause of cyanotic disease in newborn infants
Associated with ASD and VSD
Permit exchange of systemic and pulmonary circulation
49
whats the tetralogy of fallot
Pulmonary stenosis (obstruction of right ventricular outflow)
Ventricular septal defect (VSD)
Dextroposition of aorta (“overriding” aorta)
Right ventricular hypertrophy
50
what is vasculogenesis?
defined as the new formation of a primitive vascular network
51
whats angiogenesis?
defined as the growth of new vessels from pre-existing blood vessels
52
true or false: each primitive aorta l part has a ventra
false it has dorsal as well
53
After the fusion of two endothelial tubes the two ventral aortae partially fuse to form...
aortic sac
54
what do aortic branches arise from?
aortic sac
55
when does the pharyngeal arches develop?
4th and 5th week
56
do each arch receive artery? its own nerve and
yes
57
when is it called aortic arches?
when Pharyngeal arteries communicate with aortic branches
58
how many arches are formed on each side?
6 aortic arches
59
where do aortic arches terminate?
dorsal aorta
60
what is the fate of arches 1 and 2?
The 1st and 2nd arches disappear early, remnant of the 1st arch forms part of the maxillary artery
61
what is the fate of arch 3?
The 3rd aortic arch constitutes the commencement of the internal carotid a., and is therefore named the carotid arch
62
what is the fate of arch 4
The 4th right arch forms the right subclavian,
| The 4th left arch constitutes the distal part of aortic arch
63
what is the fate of arch 5
The 5th arch either never forms or forms incompletely and then regresses.
64
what is the fate of arch 6
The proximal part of the 6th right arch persists as the proximal part of the right pulmonary artery
The 6th left arch gives off the left pulmonary a. and forms the ductus arteriosus; within 1–3 months, the ductus is obliterated and becomes the ligamentum arteriosum
65
when does aberrant subclavian artery occur?
with regression of the right aortic arch 4 and the right dorsal aorta, the right subclavian artery has an abnormal origin on the left side. To supply blood to the right arm, this forces the right subclavian artery to cross the midline behind the trachea and oesophagus, which may constrict these organs, although usually with no clinical symptoms.
66
when does double aortic arch occur?
occurs with the development of an abnormal right aortic arch in addition to the left aortic arch, forming a vascular ring around the trachea and oesophagus, which usually causes dificutly breathing and swallowing.
67
when does patent ductus arteriosus occur?
); a condition wherein the ductus arteriosus fails to close after birth.
Early symptoms are uncommon, but in the first year of life include increased 'work of breathing' and poor weight gain. An uncorrected PDA may lead to congestive heart failure with increasing age.
68
when does coarctation of the aorta occur?
a congenital condition wherein the aorta is narrow, usually in the area where the ductus arteriosus (ligamentum arteriosum after regression) inserts. The word “coarctation” means narrowing. Coarctations are most common in the aortic arch. Can be proximal to ductus arteriosus (preductal) or distal to it (postductal). (Co = Coarctation site).
69
what supplies the placental circulation?
left umbilical vein
| umbilical artery
70
what supplies the vitelline circulation?
vitelline vein
| vitelline artery
71
what are the three major areas of the embryo?
```
vitelline = yolk sac
umbilical = placental
cardinal = rest of body
```
72
whats the fate of umbilical arteries before birth?
Paired branches of the dorsal
| aorta to placenta
73
whats the fate of umbilical arteries after birth?
Proximal portion persists as internal iliac and superior vesical branches to urinary bladder
74
whats the function of vitelline veins?
Carrying blood from the yolk sac to the sinus venosus
75
whats the function of umbillical veins?
originate from chorionic villi of placenta carrying oxygenated blood to the embryo
76
whats the function of cardinal veins?
draining the body of embryo
77
where does vitelline, umbilical and cardinal veins drain to?
right atrium
78
when does the lymphatic system develop
end of 6th week around the main veins
79
when do the 6 lymph sacs develop?
end of embryonic period
80
do lymphatic vessels join lymph sacs?
yes they do, but later
81
what are the three foetal and neonatal circulations?
Ductus venosus
Oval foramen
Ductus arteriosus
82
whats the function of the Ductus venosus
shunts left umbilical vein blood flow directly to IVC: allows oxygenated blood from the placenta to bypass the liver
83
whats the function of the oval foramem
allows blood to enter the left atrium from the right atrium: allows blood to bypass the lungs
84
whats the function of ductus arteriosus?
allows blood that still escapes to the right ventricle to bypass the lungs
85
what becomes ligamentum venosum of the liver?
ductus venosus
86
what closes after birth by tissue proliferation and adhesion of septal structures?
oval foramen
87
what obliterates to form ligamentum arteriosum
ductus arteriosus
88
which gender is patent ducts arteriosus more common in?
females
89
whats the cause of patent ductus arteriosus?
Failure of muscular wall to contract, respiratory distress syndrome (Low O2) and lack of surfactant in the lungs
90
whats the cause of coarctation of aorta?
Incorporation of muscle tissue of DA into arch of aorta (during development). When DA contracts after birth, part of the arch also constricts
Genetic / environmental factors
