Cardiovascular system Flashcards
0
Q
What do angioblastic cords form?
A
these cords canalize to form small endocardial tubes
1
Q
Where do angioblastic cords develop?
A
develop in cardiogenic mesoderm on both sides of embryo in week 3
2
Q
What is the sinus venosus?
A
The sinus venosus is a large quadrangular cavity which precedes the atrium on the venous side of the chordate heart. In humans, it exists distinctly only in the embryonic heart, where it is found between the two venae cavae
3
Q
Where does the sinuatrial orifice slide to?
A
gradually moves to the right side of the primordial atrium
4
Q
What happens to the left:
- vitelline vein? - umbilical vein? - common cardinal vein?
A
- left vitelline vein, umbilical vein and common carinal vein regress
- small portion exists as coronary sinus
5
Q
The right vitelline vein in the right sinus horn contributes to what?
A
Inferior vena cava
6
Q
The right anterior and common cardinal veins in the right sinus horn contribute to what?
A
Superior vena cava
7
Q
What is the sinus venarum of right adult atrium?
A
smooth part of the adult right atrium derived from sinus venosus
8
Q
What are the pectinate muscles?
- Where are they located?
A
located in areas of adult atrium derived from primordial atrium
- includes the right auricle - located in the walls of the right atrium
9
Q
What is the crista terminalis?
A
Internal ridge demarcating transition between sinus venarum and “atrium”
10
Q
What is the sulcus terminalis?
A
external shallow groove demarcating the transition between sinus and “atrium”
11
Q
Where does the primordial pulmonary vein grow from?
A
grows as dorsal outgrowth from the dorsal atrial wall just left of septum primum
12
Q
How many branches does the primordial primary veins develop?
A
4
13
Q
Where do the 4 branches (pulmonary veins) get incorporated into?
A
left atrium
14
Q
Why is the adult left atrium almost entirely smooth?
A
represents the incorporation of the pulmonary veins
15
Q
Where are the pectinate muscles located in the left atrium?
A
located in areas of the adult atrium derived from primordial atrium
- limited to left auricle
16
Q
What is the interventricular septum?
A
begins as median ridge from floor of ventricle near apex
17
Q
Where does the muscular IV septum grow from?
A
myoblasts proliferate and grow toward endocardial cushions
18
Q
Where does the membranous IV septum grow from?
A
mesenchyme grows from endocardial cushions toward muscular IV septum
19
Q
Where is the interventricular foramen?
A
present between free edge of muscular IV septum and endocardial cushions
20
Q
What causes the interventricular foramen to close in week 7?
A
when the membranous and muscular IV septa fuse
21
Q
How do trabeculae carnae develop?
A
form as the ventricular walls cavitate
22
Q
How do papillary muscles and chordae tendinae develop?
A
develop in specific locations
- papillary from myocardium - chordae tendinae from left over connecting tissue of myocardium
23
Q
How do AV valve membranes develop?
A
develop from endocardial cushions
24
How is the single heart tube formed?
folding of the embryo allows for the fusion of the small endocardial tubes to form the heart tube
25
What day does the heart tube begin beating?
day 22
26
When can blood flow be detected by ultrasonography?
week 4
27
What and where is the endocardium?
thin endothelial lining of heart tube in the embryonic heart
28
What and where is myocardium?
derived from splanchnic mesoderm around the pericardial cavity in the embryonic heart
29
What and where is cardiac jelly?
gelatinous connective tissue layer between endocardium and myocardium in the embryonic heart
30
What about epicardium in the embryonic heart?
epicardium will grow from mesothelium later on
31
Where is the bulbis cordis?
cranial end of heart tube
32
Where and what is the truncus arteriosus?
contained within the bulbis cordis and is the origin of the arterial tree
- fixed in place by association with pharyngeal arches
33
When the embryonic heart elongates and develops it develops what dilations and constrictions?
- bulbis cordis
- primordial ventricle
- primordial atrium
- sinus venosus
34
Where is the sinus venosus?
| - what is it?
caudal end of heart tube
- receives the venous return
- fixed in place by association with septum transversum
35
Common cardinal veins return from where?
provide venous return from embryo
36
Vitelline veins return from where?
provide venous return from umbilical vesicle
37
Umbilical veins return from where?
provide venous return from placenta
38
How is blood circulated through the embryonic heart in week 4 and by what means?
- via peristaltic waves
- venous return => sinus venosus which passes through sinuatrial valves => atrium which passes through AV canal => primordial ventricle which is then pumped through bulbis cordis and truncus arteriosus into the aortic sac and distributed into pharyngeal arteries and dorsal aortas
39
Where does the bulboventricular loop occur?
forms as bulbis cordis and ventricles grow faster than other parts of heart tube
40
Where does the atrium and sinus venosus end up?
atrium and sinus venosus come to lie dorsally and cranially
41
Where does the bulbis cordis and ventricle end up?
bulbis cordis and ventricle come to lie ventrally and caudally
42
Where does the heart bulge into?
the pericardial cavity
43
What adheres to the heart as it grows?
epicardium (visceral pericardium)
44
Where is the heart initially suspended?
suspended to dorsal wall of pericardial cavity by dorsal mesocardium
45
How does the transverse pericardial sinus form?
forms when a gap develops in the degenerating dorsal mesocardium
46
Where is the transverse pericardial sinus located?
located at the base of the heart between the great vessels
47
Where is thee oblique pericardial sinus located?
located posterior to heart inferior to the pulmonary veins
48
When does the partitioning of the heart occur?
weeks 4-8
49
How do endocardial cushions form?
form on dorsal and ventral walls of AV canal
50
How do endocardial cushions develop?
develop as mesenchyme infiltrates into the cardiac jelly
51
What does fusion of the endocardial cushions result in the formation of?
Left and Right AV canals
52
What is the development fate of the endocardial cushions?
- function as atrioventricular valves
| - contribute to the formation of the membranous interventricular septum
53
What is the septum primum?
thin, crescent shaped membrane
54
Where does the septum primum grow from?
grows from roof of primordial atrium toward endocardial cushions
55
What does the septum primum accomplish?
partially divides the common primordial atrium into left and right halves
56
Where is the formamen primum located?
located between the edge of septum primum and endocardial cushions
57
What is the function of the foramen primum?
functions as shunt between right and left atria
58
What eventually happens to the foramen primum?
eventually disappears as septum primum fuses with endocardial cushions
- the fused septum primum now becomes the primordial atrial septum
59
Where does the foramen secundum form?
forms in the central part of septum primum (prior to closure of foramen primum)
60
What is the function of the foramen secundum?
ensures oxygenated blood can continue moving from right atrium to left atrium
61
What is the septum secundum?
thick, muscular crescent shaped fold
62
Where does the septum secundum grow from?
- grows from ventral wall of right atrium
| - grows immediately adjacent to septum primum (on the right side)
63
What does the septum secundum overlap in the septum primum?
the foramen secundum
64
How does the foramen ovale persist?
persists as the septum secundum doe not completely partition the atria
65
What does the foramen ovale do?
allows blood from right atrium to pass through foramen secundum to left atrium
66
What happens to the cranial part of septum primum?
- breaks down
| - effectively elliminates foramen secundum and leaves only foramen ovale
67
What happens to the caudal part of septum primum?
- persists
| - functions as the valve for foramen ovale
68
How does blood pass from right to left atrium prior to birth?
- high right atrial pressure => pushes septum primum open => allows blood to pass through foramen ovale to left atrium
69
How does blood pass from right to left atrium after birth?
- left atrial pressure is high => pushes septum primum closed => prevents blood from passing through foramen ovale (from left atrium to right atrium)
70
By age 3 months, what happens to the septum primum?
fuses with septum secundum
71
What is the fossa ovale?
adult remnant of the closed foramen ovale
72
What are bulbar and truncal ridges
- form as result of neural crest infiltration and proliferation
73
What do bulbar and truncal ridges fuse to form?
undergo 180 degree spiral fuse to form aorticopulmonary septum
74
What is the truncus arteriosus subdivided into?
- ascending aorta
| - pulmonary trunk
75
What is the bulbus cordis incorporated into the definitive ventrical as?
- conus arteriosus
| - aortic vestibule
76
What is the conus arteriosus?
- in the right ventricle
| - leading to the pulmonary semilunar valve
77
What is the aortic vestibule?
- in the left ventricle
| - leading to aortic semilunar valve
78
What does each semilunar develop from?
develops from 3 swellings of subendocardial tissue
| - at the orifice leading to either the ascending aorta or pulmonary trunk
79
What do the semilunar valves thin out to form?
form the lunule and sinus of each valve leaftlet
80
The SA node develops in what week?
5th week
81
where does the AV node form?
forms in the wall of sinus venosus
82
Where is the SA node incorporated?
incorporated into right wall of sinus venarum near the orifice of the SVC
83
Where does the AV node form?
forms at the base of the interatrial septum and superior to the endocardial cushions
84
Where is the AV node located?
located just anterior to the orifice of the coronary sinus
85
Where does the AV bundle pass?
passes from interatrial septum to interventricular septum
86
What will the fibrous CT form and where?
the cardiac skeleton in the region of the endocardial cushions
87
What does the cardiac skeleton do?
helps separate atrial electrical activity from ventricular electrical activity
88
What is the abnormality in dextrocardia?
heart tue bends to the left rather than the right
89
how common is dextrocardia?
most frequent cardiac positional abnormality
90
Where is the heart displaced in dextrocardia?
heart is displaced to the right side of thorax
91
Dextrocardia transposes what?
great vessels and heart chambers
92
When does dextrocardio function normaly?
when associated with situs inversus
| - transposition of abdominal viscera
93
What is dextrocardia associated with when it occurs in isolation?
frequently associated with other cardiac abnormalities
94
How common is ectopia cordis?
extremely rare
95
What is ectopia cordis?
heart is partially or completely exposed at surface of thoracic wall
96
How is ectopia cordis caused?
due to failure of lateral body folds to fuse in the midline
97
Is ectopia cordis fatal?
yes, fatal a few days after birth due to cardiac failure or infection
98
How common is atrial septal defects?
fairly common and more often in women (3:1)
99
How many people have a probe patent foramen ovale?
25%
100
If the patent foramen ovale is small, is there a functional problem?
No
101
Hemodynamic changes may occur in a patent foramen ovale is what is present?
other cardiac anomalies
102
If other cardiac anomalies are present what happens to venous blood in a patent foramen ovale?
results in shunting of venous blood to left atrium producing cyanosis
103
What are the most common causes for Atrial Septal Defects (ASD)?
incomplete adhesion of septum primum and septum secundum due to:
- abnormal septal growth
- abnormal foraminal perforations
patent foramen primum:
- due to failure of septum primum to fuse with endocardial cushions
- may be associated with AV valve or AV septal defects as well
104
What is the most common type of congenital heart defect?
Ventricular Septal Defects
105
Ventricular septal defects are more common in what sex?
more common in males
106
What do the ventricular septal defects usually involve?
usually involve the membranous interventricular septum
107
Ventricular septal defect are a failure to grow from what?
endocardial cushion
108
What does the ventricular septal defects result in?
incomplete closure of the IV foramen
109
What do large IV foramen defects in ventricular septal defects result in?
pulmonary hypertension
| - leads to dyspnea and cardiac failure early in infancy
110
What is persistent truncus arteriosus?
failure of truncal ridges to form aorticopulmonary septum
111
What is persistent truncus arteriosus associated with?
Ventricular septal defects
112
What happens in persistent truncus arteriosus?
single arterial trunk arises from heart and straddles both ventricles
- supplies systemic, pulmonary and coronary arterial systems
113
What is transposition of the great arteries due to?
due to failure of aorticopulmonary septum to spiral normally
- aorta arises from right ventricle
- pulmonary trunk arises from left ventricle
114
What is the transposition of the great arteries associated with?
Atrial septal defects and ventricular septal defects
- allows some mixing of blood between pulmonary and systemic circulation
- most common cause of cyanotic heart disease
115
Is transposition of the great arteries fatal?
fatal if not surgically corrected
116
What 4 defects is tetralogy of Fallot consisted of?
- pulmonary trunk stenosis
- dextroposition of aorta
- due to unequal division of the truncus arteriosus
- ventricular septal defect
- right ventricle hypertophy
- most or all of the right ventricle output is through aorta
- pulmonary circulation is dependent on patent ductus arteriosus
- provides flow from aorta into pulmonary trunk
