Cardiovascular Embryology Flashcards
1
Q
the heart and blood vessels are derived from
A
- mesoderm
2
Q
heart forms and begins beating in which week of development?
A
- week 4
3
Q
longitudinal folding does what?
A
- moves the heart into the newly formed thorax
4
Q
transverse folding does what?
A
- creates 3D trunk
- brings right and left sides together in ventral midline
5
Q
development of all blood-carrying vessels
A
- mitosis of angioblasts to form clusters
- lumens develop
- vessel walls create blood cells
- fusion of neighbor vessels to form network of interconnected vessels.
6
Q
development of blood-carrying vessels occurs during which week?
A
- week 3
7
Q
early circulation
A
- embryo already large enough to need heart and vessels to carry blood everywhere
8
Q
where does the heart pump blood in week 4?
A
- body
- placenta
9
Q
what do arteries and veins supply in week 4?
A
- body
- placenta
10
Q
how long does it take for the heart to develop?
A
- 5.5 weeks
11
Q
hearts starts out as
A
- right and left blood vessel (angioblastic cords)
12
Q
transverse folding heart development
A
- brings 2 cords together in anterior midline
- fuse and creates one heart tube
- develops all 3 layers
13
Q
the heart tube begins to beat on which day?
A
- Day 22-23
14
Q
composition of heart tube
A
- single, straight tube
- subdivided into regions
15
Q
blood flow through tube
A
- sinus venosus
- atrium
- ventricle
- bulbus cordis
- truncus arteriosus
16
Q
sinus venosus becomes part of
A
- right and left atria
17
Q
bulbous corgis becomes part of
A
- right and left ventricles
18
Q
truncus arteriosus becomes part of
A
- aorta
- pulmonary trunk
19
Q
heart tube folding
A
- atrium and ventricle change their locations and acquire their permanent positions
20
Q
final positions after heart tube folding
A
- ventricles located anteriorly
- atria located posteriorly
21
Q
important central structure in subdivision of atrium and ventricles
A
- endocardial cushion
22
Q
what is one thing you always need to subdivide the atrium
A
- always need a hole in the wall between the atria
23
Q
atrial subdivision step 1
A
- septum primum grows from roof to endocardial cushion
24
Q
atrial subdivision step 2
A
- first hole is foramen primum that forms
- later disappears
25
atrial subdivision step 3
- holes form in septum
26
atrial subdivision step 4
- coalesce to form foramen secundum
27
atrial subdivision step 5
- septum secundum grows to right side of septum primum, from roof to endocardial cushion
28
atrial subdivision step 6
- foramen ovale is the hole in the septum secundum
29
septum secundum covers the
- foramen secundum
30
the openings in atrial subdivision
- foramen ovale
| - foramen secundum
31
blood flow in fetal heart
- right atrium
- foramen ovale
- foramen secundum
- left atrium
32
why is pressure different in fetal heart
- due to pressure differences in atria
| - prenatal shunt
33
septum primum in early fetal heart
- pushed to left and acts as an open valve of foramen ovale
34
subdivision of ventricle requires
- no hole is required in the septum
35
subdivision of the ventricle process
- interventricular septum grows from floor to endocardial cushion
- closes interventricular foramen
36
development of the atrioventricular valves
- arise from the endocardial cushion
37
role of truncus arteriosus
- subdivides into aorta and pulmonary trunk/artery
38
development of truncus arteriosus
- forming longitudinal aorticopulmonary septum
| - PLUS twisting to achieve final positions
39
what does the fetus use for breathing
- not its lungs. uses amniotic sac
| - so they don't need much blood to the lungs
40
2 arteries in prenatal circulation
purpose
- umbilical arteries
| - blood from iliac artery to placenta
41
vein in prenatal circulation
purpose
- umbilical vein
| - placenta -> inferior vena cava
42
3 shunts in prenatal circulation
- ductus venosus
- oval foramen
- ductus arteriosus
43
purpose of ductus venosus
- help umbilical vein bypass liver
44
location of oval foramen
- between heart atria
45
purpose of oval foramen
- bypass pulmonary circulation
46
blood flow with oval foramen
- blood flows right atrium -> left atrium
47
location of ductus arteriosus
- between pulmonary artery and aorta
48
purpose of ductus arteriosus
- bypass pulmonary circulation
49
blood flow with ductus arteriosus
- pulmonary artery -> aorta
50
PO2 of umbilical vein
- 30 mmHg
51
O2 sat of umbilical vein
- 80% O2 sat
52
most inferior vena cava blood through oval foramen
- oval foramen -> LA -> LV -> aorta -> upper body
53
most superior vena cava blood through oval foramen
- RA -> RV -> pulmonary artery
54
most pulmonary artery blood through ductus arteriosus
- goes to the lower body
55
remnant name of umbilical vein
- ligamentum teres
56
remnant name of umbilical arteries
- medial umbilical ligaments
57
remnant name of ductus venosus
- ligamentum venosum
58
when does the ductus venous close
- closes at birth
| - permanent by 1 week
59
remnant name of oval foramen
- oval fossa
60
when does the oval foramen close
- closes at birth by septum primum valve
| - permanent by 5 years
61
remnant name of ductus arteriosus
- ligamentum arteriosum
62
when does the ductus arteriosus close
- constricts by 10 hours
- closes by 24 hours
- permanent by 1-2 months
63
what drug closes a ductus
- indomethacin
64
how do you keep a ductus open?
- prostaglandins E1 and E2
65
transition from prenatal to postnatal life
- baby takes a breath
- pulmonary artery resistance decreases
- blood flows into lungs through pulmonary artery
- pulmonary venous blood flows into left atrium
- left atrial pressure becomes greater than right atrial pressure
66
what happens when left atrial pressure becomes greater than right atrial pressure
- septum primum valve pushed against septum secundum valve and covers oval foramen
