Embryology Flashcards

1
Q

name the four major stages of heart development

A
  1. primitive heart tube
  2. heart looping
  3. atrial and ventricular septation
  4. outflow tract septation
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2
Q

what does the lateral plate of the splanchnic mesoderm form in the 3rd week?

A

the circulatory system (as well as other mesoderm)

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3
Q

what do the angiogenic cell islands do in the third week?

A

they collect in the lateral plates splanchnic mesoderm and move towards the midline where the coalesce to form two primitive heart tubes

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4
Q

when does the primordial heart begin to function?

A

at the beginning of week 4

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5
Q

why does the cardiovascular system need to develop first?

A

the rapidly growing embryo cannot get enough nutrition via diffusion

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6
Q

where do blood vessels first appear?

A

in the wall of the yolk sac, allantois, connecting stalk and chorion

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7
Q

where do paired endothelial strands (angioblastic cords) appear in week three?

A

in the cariogenic mesoderm

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8
Q

what do angioblastic tubes canalise to form?

A

heart tubes

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9
Q

from what is the pericardium derived from?

A

from the intra-embryonic coelom

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10
Q

what are the parietal and fibrous pericardium formed from?

A

the somatic mesoderm

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11
Q

what is the visceral layer of the pericardium formed from?

A

the splanchnic mesoderm

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12
Q

during cephalic folding what structure becomes ventral?

A

the pericardial cavity

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13
Q

during cephalic folding what structure becomes dorsal?

A

the cardiac tube

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14
Q

name the 5 parts of the primitive cardiac tube from cranial end to caudal end

A
> truncus arteriosus
> bulbus cordis
> ventricle
> atrium
> sinus venosus
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15
Q

name the three veins that supply the sinus venosus horns

A

> common cardinal
umbilical
vitelline

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16
Q

where does the vitelline vein get its blood from?

A

the yolk sac

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17
Q

where does the common cardinal vein get its blood from?

A

the body of the embryo

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18
Q

where do the aortic arches arise?

A

from the aortic sac

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19
Q

where do the aortic arches terminate?

A

in the dorsal aorta

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20
Q

how is the bulboventricular loop formed?

A

the bulbus cordis and the ventricle grow faster than the other regions forming a U-shaped bulboventricular loop by day 24

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21
Q

what is dextrocardia?

A

there is situs invertus where the heart loops to the right side so it is facing the right

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22
Q

what does the endocardial cushion formation separate?

A

the right atrioventricular opening from the left atrioventricular opening

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23
Q

what does the septum formation separate?

A

he right atrium from the left atrium and the right ventricle form the left ventricle

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24
Q

which septum first grows down from the endocardial tissue?

A

the septum primum

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25
between what is the foramen ovalis?
the septum secundum and the septum primum
26
what is the opening between the septum primum and the endocardial cushion called?
ostium primum
27
where does the foramen secundum form?
at the end of the septum primum due to cell death
28
what grows and overlaps the foramen secundum?
the septum secundum
29
is the foramen secundum an opening in the septum primum or secundum?
in the septum primum
30
what is the role of the oval foramen before birth?
this allows most of the blood to pass from the right atrium to the left atrium preventing the passage of blood in the opposite direction
31
what happens to the septum primum after birth?
it fuses with the septum secundum
32
what is the name of the condition that occurs due to non-closure of the oval fossa?
atrial septal defect, hole in the heart
33
name four clinically significant types of atrial septal defect
> foreamen secundum defect > endocardial cushion defect (with foreamen primum defect) > sinus venosus defect > common atrium
34
what forms first during the partitioning of primordial ventricle?
the muscular ventricular septum
35
during the partitioning of the primordial ventricle what happens to the aorticopulmonary septum?
it rotates and fuses with muscular ventricular septum to form the membranous interventricular septum closing the interventricular foramen
36
what happens to the endocardial cushion in the partitioning of the primordial ventricle?
it grows to separate the atria from the ventricles. it contributes to both atrial septation distally and membranous portion of the interventricular septum proximally.
37
in the partitioning of the bulbus cordis and truncus arteriosus what is formed via the spiralling?
aorticopulmonary septum
38
during the partitioning of the bulbus cordis and truncus arteriosus what proliferates in their walls?
mesenchymal cells (neural crest)
39
what is the most common congenital heart disease?
ventricular septal defect
40
where do ventricular septal defects occur?
in any part of the septum
41
when does the sinoatrial node develop?
during the 5th week of development
42
from what does the atrial ventricular node develop from?
from cell of the atrial ventricular canal and sinus venous
43
what is the cause of sudden infant death syndrome?
abnormalities of conducting tissue
44
what is the fate of the aortic sac?
it becomes the aortic arches
45
what is the fate of the bulbus cordis?
it becomes the right ventricle and parts of the outflow tract
46
what is the fate of the primitive ventricle?
it becomes the left ventricle
47
what is the fate of the primitive atrium?
it becomes parts of the right and left atria
48
what is the fate of the sinus venous?
it becomes the superior vena cava and right atrium
49
name two congenital heart diseases that are more common in females?
atrial septal defect and patent ductus arteriosus
50
what does transposition of the great vessels permit?
exchange of systemic and pulmonary circulation
51
state two causes of transposition of great vessels
> failure of aorticopulmonary septum to take part in a spiral course > defective migration of neural crest cells
52
what four cardiac defects make up tetralogy of fallout?
> pulmonary stenosis > ventricular septal defect > dextroposition of aorta > right ventricular hypertrophy
53
define vasculogenesis
new formation of a primitive vascular network
54
define angiogenesis
growth of new vessels from pre-existing blood vessels
55
what are the first arteries to appear in the embryo?
the left and right primitive aorta
56
what two parts make up the primitive aorta?
a ventral part and a dorsal part
57
what do the two ventral aortae partially fuse with?
eachother to form the aortic sac
58
what do the aortic branches arise from?
the aortic sac
59
when do the pharyngeal arches develop?
during the 4th and 5th week
60
what do the pharyngeal arteries communicate with?
the aortic branches/arches
61
overall how many aortic arches develop from the aortic branches and pharyngeal arteries?
6 pairs
62
where do the aortic arches terminate?
the dorsal aorta
63
what is the fate of the 1st and 2nd arches?
they disappear early but the remnant of the 1st arch forms part of the maxillary artery
64
what happens to the 3rd aortic arch?
it constitutes the commencement of the internal carotid artery and is named the carotid arch
65
what happens to the right 4th aortic arch?
it forms the right subclavian vein
66
what does the left aortic arch constitute?
the distal part of the aortic arch
67
what happens to the 5th arch?
this never forms or forms incompletely and then regresses
68
what happens to the 6th right aortic arch?
this persists as the proximal part of the right pulmonary artery
69
what happens to the 6th left aortic arch?
this gives off the left pulmonary artery and forms the ductus arteriosus. the ductus arteriosus is obliterated and becomes the ligamentum arteriosum
70
describe aberrant subclavian artery
regression of the 4th aortic arch and the right dorsal aorta means the right subclavian artery originates abnormally on the left side. this forces it to cross the midline posterior to the trachea and oesophagus, this may cause constriction of these organs but usually has no clinical symptoms
71
what is a double aortic arch?
there is development of an abnormal right aortic arch in addition to the left forming a vascular ring around the trachea and oesophagus which can create difficulty breathing and swallowing
72
describe a patent ductus arteriosus abnormality
this is when the ductus arteriosus fails to close after birth. in the first year of life there will be working for breath, poor weight gain. this may lead to congestive heart failure later in life
73
what is coarctation of the aorta?
a congenital condition where the aorta narrows, usually where the ligamentum arteriosum intersects
74
what is the function of the vitelline arteries in embryo?
they supply the yolk sac
75
what are the vitelline arteries represented by in adults?
> celiac artery: of the foregut > superior mesenteric artery: of the midgut > inferior mesenteric artery: of the hindgut
76
what happens to the proximal part of the umbilical arteries after birth?
they persist as internal iliac and superior vesical branches (to the urinary bladder)
77
what happens to the distal part of the umbilical arteries after birth?
they degenerate to form the obliterated umbilical arteries. they also form the medial umbilical
78
name the four vitelline veins which drain the yolk sac
> portal vein > hepatocardiac > liver sinusoids > superior mesenteric
79
what happens to the right umbilical vein?
it degenerates completely
80
what happens to the left umbilical vein?
it obliterates and forms ligamentum teres of the adult liver
81
what happens to the ductus venosus?
it obliterates and forms ligamentum venosum
82
what is the function of the ductus venosus in the foetus?
it shunts a portion of left umbilical vein blood flow directly to the inferior vena cava thus allowing oxygenated blood from the placenta to bypass the liver
83
what is the main venous drainage system of the embryo?
the cardinal veins
84
what does the cardinal system consist of?
anterior, posterior and common cardinal veins draining into the sinus venous
85
what system do the cardinal veins form and how?
the vena caval system by anastomosis among the veins
86
name 4 venous system abnormalities
> double inferior vena cava > absence of inferior vena cava > left superior vena cava > double superior vena cava
87
when does the lymphatic system develop?
at the end of the sixth week
88
how many primary lymph sacs develop at the end of the embryonic period?
6
89
what is the function of the ductus arteriosus?
it allows blood that escapes the right ventricle to by pass the lungs
90
describe the foetal circulation from the aorta to the umbilical vein
aorta > descending aorta > abdominal aorta > common iliac artery > umbilical arteries > placenta > umbilical vein