Development Flashcards
(127 cards)
1
Q
Why does the heart migrate from neck into thorax
A
because cardiogenic mesoderm migrates to cranial most part of the embryo
2
Q
What does the heart tube arise from
A
paired endothelial lined tubes
3
Q
at what end does the heart tube receive blood and pump blood
A
receives at the caudal end and pumps at the cranial end
4
Q
When does cardiac looping begin and what are the 4 dilations
A
Day 22 bulbus cordis ventricle atrium sinus venosus
5
Q
When does the heart start beating
A
Day 22
6
Q
Why does the heart loop
A
ventricles grow faster than other regions
7
Q
Which way does the cranial portion of the heart tube bend
A
ventrally, caudally and to the right
8
Q
which way does the caudal portion of the heart tube bend
A
dorsally, cranially and to the left
9
Q
What becomes of the sinus venosus
A
left sinus horn becomes coronary sinus
right sinus horn becomes part of right atrium as sinus venarum
10
Q
What will the primitive atrium form
A
left and right auricles
11
Q
What grows into the left atrium during final steps of development
A
the pulmonary vein
12
Q
What is incorporated into the right atrium during final steps of development
A
sinus venosus
13
Q
What will the primitive ventricle become
A
trabeculated portion of left ventricle
14
Q
What are the 3 parts of the bulbus cordis
A
caudal, conus cordis and truncus cordis
15
Q
what becomes of the caudal part of bulbus cordis
A
trabeculated region of right ventricle
16
Q
what becomes of the conus cordis part of bulbus cordis
A
outflow of both ventricles, right= conus arteriosus and left=aortic vestibule
17
Q
what becomes of the truncus arterioles part of bulbus cordis
A
pulmonary trunk and aorta
18
Q
Describe pathway of blood in the developing heart around day 30
A
blood enters sinus venous-> primitive atrium -> primitive ventricle -> bulbus cordis ->aortic sac -> embryo
19
Q
What week do coordinated contractions of the fetal heart begin
A
week 4
20
Q
What is the first step of partitioning of the atrium
A
septum primum forms, day 30
21
Q
What is the second step in partitioning of the atrium
A
ostium primum forms, day 30
22
Q
what is the third step in partitioning of the atrium
A
ostium primum closes, day 33
23
Q
What is the fourth step in partitioning of the atrium
A
ostium secundum opens via apoptosis, day 33
24
Q
What is the fifth step in partitioning of the atrium
A
septum secundum forms, day 33
25
what is the sixth step in partitioning of the atrium
foramen ovale forms, because septum secundum is incomplete
26
What is the original septum primum known as in a newborn
the valve of foramen ovale
27
prenatally where is the pressure greatest in the heart
on the right side
28
postnatally where is the pressure gradient of the heart
on the left side
29
The heart valves form from what tissue type
neural crest cells, endocardial cushions
30
Why is the right ventricle not in contact with the atria like the left in development
bulboventricular flange regresses during week 5
31
What are the 2 portions of the interventricular septum. state their origins
muscular portion from mm of ventricle and membranous portion from endocardial cushions
32
When does partitioning of the ventricles take place
week 7
33
where are the conotruncal ridges derived form that form pulm trunk and aorta
neral crest cells
34
how many degress of spiraling do the conotruncal ridges undergo
180 degrees
35
what is the aorticopulmonary septum
spiraled conotruncal ridges
36
what does the conus cordis form
conus arteriosus and aortic vestibule aka right and left ventricles
37
what does the truncus arteriosus form
pulmonary trunk and ascending aorta
38
where do the semilunar valves form from
neural crest of conotruncal ridges
39
Ventricular septal defects account for what percent of congenital heart defects
30%
40
what are the 2 types of ventricular defect and which is most common
membranous- msot common
| and muscular
41
the severity of a ventricular septal defect reflects what, and what is the usual result
size of defect and results in left to right blood shunting
42
Atrial septal defects account for what percent of congenital heart defects
10%
43
What are the various types of atrial SD
ostium secundum is too big
ostium primum- endocardial defect
common atrium- no atrial septum
44
what is the often result of ASDs
left to right blood shunting
45
What is the result of underdeveloped endocardial cushions
persitent atriocentricular canal
ostium primum defect
membranous interventricular septum defect
46
What percentage of congenital heart defects are Pulmonary and aortic valave stenosis
pulmonary- 7%
| aortic 6%
47
What additional condition is likely with pulmonary and aortic valve stenosis
patent foramen ovale and ductus arteriosus
48
What causes tetralogy of fallot
unequal division of truncus arteriosus by conotruncal ridges
49
what are the 4 components of tetralogy of fallot
overriding aorta
pulmonary stenosis
ventricle septal defect
right ventricular hypertrophy
50
What causes transposition of Great vessels
conotruncal ridges fail to spiral
51
In a patient with transposition of the great vessels what else would you expect to see
patent ductus arteriosus and patent foramen ovale
52
What causes persistent truncus arteriosus
conotruncal ridges fail to form
53
What causes DiGeorge Syndrome
deletion on long arm Chromosome 22
54
What is the result of a long arm chrom 22 deletion
abnormal neural crest development leading to many cardiac abnormalities like defects of conotruncal formation
55
What are other signs of DiGeorge Syndrome
Craniofacial defects, thymic hypoplasia, parathyroid dysfunction- hypocalcemia, cleft palate CATCH22
56
What is dextrocardia
heart lies in right thorax
57
what causes dextrocardia
heart loops in opp direction
58
What causes ectopic cordis
failure of ventral body wall to close
59
what is ectopic cordis
heart lies on surface of chest
60
What do mesodermal cells differentiate into unde VEGF
blood islands
61
What do blood islands produce
hemangioblasts
62
They major embryonic arterial and venous systems arise via what process
vasculogenesis
63
What is the definition of angiogenesis
sprouting and growth of already existing vessels
64
What are the 3 primary vascular systems of the embryo/fetus
Intraembryonic
Yolk sac (vitelline)
Placental
65
What vessels are within the intraembryonic system
aortic arch aa and the cardinal veins
66
what vessels are within the yolk sac system
vitelline artery and vein
67
what vessels are within the placental system
2 umbilical aa and 1 umbilical vein
68
How many aortic arch pairs are there originally and where do they originate from?
6 pairs from aortic sac(truncus arteriosus)
69
Where do the aortic arch aa drain
dorsal aortae- paired cranially join caudally
70
What does the aortic arch become
proximal aortic arch and the brachiocephalic artery
71
What does the first aortic arch a become
regresses..maxillary a
72
what does the second aortic arch branch become
regresses (stapedial)
73
What does the third aortic arch artery become
common carotid aa
74
What does the 4th aortic arch aa turn into
R- R subclavian a
| L- portion of aortic arch
75
What does the 5th aortic arch aa turn into
regresses completely
76
What does the sixth aortic arch aa turn into
R- pulmonary a
| L- pulmonary a and ductus arteriosus
77
What does 7th intersegmental a turn into
R- part of right subclavian
| L- left subclavian
78
What does the ductus arteriosus become in an adult
ligamentum arteriosum
79
Where does the right recurrent laryngeal n travel
loops around subclavian (4th branch) because 5 and 6 regress
80
Where does the left recurrent laryngeal n travel
loops around arch of aorta near ligamentum arteriosum
81
What do the vitelline aa become
celiac, superior mesenteric and inferior mesenteric aa
82
Where are the umbilical aa in an adult
off common iliac aa, supply placenta
| turns into medial umbilical ligament
83
What is patent ductus arteriosus, results in?
ductus arteriosus does not close- blood shifts left to right and results in pulmonary hypertension
84
Which coarctation of the aorta presents at birth
preductal
85
why does postductal coarctation of the aorta usually present in early adolescence
collateral circulation is established between internal thoracic aa and intercostal aa prenatally
86
What causes retroesophageal right subclavian a
right 4th aortic arch degenerates, leaving 7th intersegmental a to form right subclavian
87
what is dysphagia lusoria
difficulty swallowing due to esophageal compression
88
What causes a double aortic arch
the right dorsal aorta between original of the 7th intersegmental a and fusion with dorsal aorta persists
89
does the double aortic arch usually cause constriction of esophagus
yes
90
What happens to the umbilical veins
right vein degenerates
| left vein carries O2blood from placenta thorugh fetal liver to heart
91
What does the left umbilical v become
ductus venosus- bypass liver
92
What cardinal veins become the azygos system
supracardinal
93
What causes an absent inferior vena cava
right sub cardinal vein fails to make a connection with hepatic part of vena cava
94
where does the blood drain in an absent inferior vena cava
azygos system
95
what causes a left superior vena cava
left common cardinal vein persists and forms a left superior vena cava
right cardinal vein degenerates
96
Where does the superior vena cava drain if it is on the left
righ atrium via coronary sinue
97
what causes a double superior vena cava
left and right common cardinal vv persists
98
Where do the superior vena cavas drain if there is a double
right- into r atrium
| left- via coronary sinus to r atrium
99
What does the lung bud give rise to
larynx, trachea, bronchi, bronchioles and alveoli
100
Where does the lung bud form form and when in development
week 4 from foregut as ventral diverticulum
101
What separates the lungbud from the esophagus
2 tracheoesophageal ridges
102
what to the tracheoesophageal ridges form when they fuse
septum
103
What occurs if there is an abnormal division of the cranial part of the foregut into respiratory and esophageal portions
tracheoesophageal fistulas
104
what is the most likely cause of a tracheoesophageal fistula
spontaneous deviation of the tracheoesophageal septum
105
What are other signs of a tracheoesophageal fistula
esophageal atresia(blind end) 90%, polyhydramnios, pneumonitis
106
What structure remains in contact with primordial laryngeal inlet after septum forms
pharynx and lung bud
107
Failure of the larynx to recanalize ocurrs in what time frame of development
between week 6 and 10
108
The trachea is fully developed by what week
12
109
describe timeframe of lung buds
week 5- lung bud divides into L and R
week 6- secondary bronchial buds
7th- tertiary bronchial buds
further branching continues postnatally
110
What is formed by dilation of terminal bronchi? what will the lungs look like.
congenital lung cysts, honeycomb appearance
111
Is abnormal division of the bronchial tree common
yes because little functional consequence
112
Weeks 5-16 what stage are the lungs in
pseudoglandular- terminal branches there bt no respiratory bronchioles hence not viable fetus
113
When do fetal breathing movements typically start
12th week development- amniotic fluid breathed in
114
Oligohydramnios affects the lungs how
lung hypoplasia
115
When is the canalicular stage of the lungs
16-26 weeks
116
When have the respiratory bronchioles and alveolar ducts formed
24 weeks
117
When do surfactant levels reach adequate amounts
26-28 weeks
118
Why are fetuses during weeks 26-28 only 50% viable
underdevelopment of alveoli
119
When is the terminal sac stage of lungs
26 weeks to 32 weeks
120
Fetuses born during terminal sac have what chance survival
80-95%
121
What are the two critical factors in derermining survival and growth of premature infants
sufficient surfactant production and adequate pulmonary vasculature
122
When is the aveolar stage of lung development
32 weeks to 8 years post natally
123
Why are lungs in newborns more dense in X rays
up to 300 million alveoli
124
Lack of surfactant production puts premature infants at risk of what syndrome
respiratory distress syndrome (hyaline membrane disease)
125
How can surfactant secretion be stimulated in utero
giving mom glucocorticoids
126
How can we treat lack of surfactant in postnatal babies
exogenous surfactant
127
Which structure carries oxygenated blood to the fetus
umbilical vein
