CVS EMBRYOLOGY Flashcards

1
Q

what are the first arteries to appear in the embryo

A

right and left primitive aortae

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

what does each primitive aorta have

A

ventral and a dorsal aorta

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

how is aortic sac formed

A

fusion of the 2 ventral aortae, then becomes an extension of the truncus arteriosus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

where do aortic arch branches arise from

A

aortic sac

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

in what weeks of pregnancy are the 6 pairs of aortic arches formed?

A

4th and 5th weeks

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

what happens during the 4th and 5th weeks of pregnancy

A

6 pairs of aortic arches are formed -> these unite with the dorsal aortae

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

what do aortic arches give rise to

A

great arteries of head and neck

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

by what 2 methods to blood vessels develop

A

vasculogenesis and angiogenesis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

what is vasculogenesis

A

new formation of a primitive vascular network

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

what is angiogenesis

A

growth of new vessels from pre-existing blood vessels

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

explain the adult derivatives of aortic arches

A

1st and 2nd arches disappear early
3rd aortic arch forms common carotid artery
4th right arch forms right subclavian artery
4th left arch forms aortic arch
5th arch disappears
6th right arch forms right pulmonary artery
6th left arch forms the left pulmonary artery & ductus arteriosus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

explain double aortic arch

A

occurs with the non-regression of the right aortic arch forming a vascular ring around the trachea and oesophagus, which usually causes difficulty in breathing and swallowing

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

explain patent ductus arteriosus (PDA)

A

common anomaly associated with maternal rubella infection in early pregnancy
cause - failure of muscular wall to contract, resp distress syndrome (low O2) and lack of surfactant in lungs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

what can an uncorrected PDA lead to

A

congestive heart failure with increasing age

can be associated with ASD, VSD, coarctation of aorta

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

explain coarctation(constriction) of aorta

A

congenital condition where aorta is narrow , usually where ductus arteriosus (ligamentum arteriosum) inserts
most common in the aortic arch
can be proximal to ductus arteriosus (preductal) or distal to it (postductal)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

what are the main theories of cause of coarctation of aorta

A

when ductus arteriosus contracts after birth, part of the arch attaching to it also constricts
genetic/environmental

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

vitelline vessels supply yolk sac

A

adult gut vessels

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

umbilical vessels supply placenta

A

internal iliac

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

cardinal vessels supply rest of body

A

SVC & IVC

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

in what week of pregnancy does lymphatic system begin to develop

A

week 6

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

explain development of lymphatic system during 6th week of pregnancy

A

develops around main veins
6 primary lymph sacs develops at the end of embryonic period
thoracic duct develops from two vessels anterior to the aorta - these become left and right embryonic thoracic ducts
left one gives rise to the upper third of the adult thoracic duct and the lower 2/3 of the adult duct are formed by right embryonic thoracic duct

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

what 2 organs does the placenta act for for the foetus

A

lungs and kidney

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

how does oxygenated blood reach foetus

A

comes from placenta and then reaches foetal IVC via umbilical vein, mostly bypassing foetal liver
blood in foetal IVC therefore mixed oxygenated and deoxygenated

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

foetus ductus venosus shunts

A

shunts blood in left umbilical vein into IVC : allows oxygenated blood from the placenta to bypass the liver

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

foramen ovale foetus shunt

A

shunts blood from right atrium to left atrium : allows blood to bypass the lungs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

ductus arteriosus foetus shunt

A

shunts blood from right ventricle and pulmonary arteries to aorta : allows blood to bypass the lungs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

ductus venosus

A

ligamentum venosum of the liver

28
Q

foramen ovale

A

fossa ovalis of the heart

29
Q

ductus arteriosus

A

ligamentum arteriosum between left and right pulmonary artery and aorta

30
Q

umbilical arteries

A

medial umbilical ligaments of anterior abdominal wall

31
Q

main stages in heart development

A
bilateral heart primordia
primitive heart tube
heart looping
atrial and ventricular septation
outflow tract septation
32
Q

what week does CVS system function

A

first major system to function in embryo and this happens in week 4

33
Q

Why does CVS function so early?

A

rapidly growing embryo - nutrition by diffusion is not sufficient to satisfy the growing embryo

34
Q

what happens during 3rd week in terms of CVS development?

A

blood vessels “islands” first appear in yolk sac, allantois, connecting stalk and chorion - this is called the cardiogenic field

35
Q

what do blood vessels in lateral plate splanchnic mesoderm form?

A

two heart tubes

36
Q

two heart tubes are formed by…

A

blood vessels in lateral plate splanchnic mesoderm

37
Q

when heart tubes fuse they form…?

A

join blood vessels in other areas to form primordial CVS system

38
Q

somatic mesoderm

A

parietal layer of serous pericardium & fibrous pericardium form from this

39
Q

splanchnic mesoderm

A

visceral layer of serous pericardium forms from

40
Q

intra-embryonic coelom

A

pericardial cavity forms from

41
Q

explain primitive heart tube - different parts

A
truncus arteriosus
bulbus cordis
primitive ventricle
primitive atrium
sinus venosus
42
Q

what happens to primitive heart tube when it gets to big

A

invaginates pericardium

because it becomes too large for pericardium it needs to fold/loop and then goes onto form bulboventricular loop

43
Q

explain formation of cardiac (bulboventricular) loop

A

bulbus cordis and ventricle enlarge and loop to right -> ventricle pushed left and inferiorly
atria are pushed superiorly and posteriorly

44
Q

explains dextrocardia

A

heart tube loops to left side (instead of right side), so ventricles come to lie facing the right (=dextro)
most frequent positional abnormality of heart

45
Q

explain partitioning of primitive heart

A
  1. single atrioventricular canal into left and right AV canals (endocardial cushion growth)
  2. the primitive atrium into left and right atria (atrial septum formation)
  3. the primitive ventricle into left and right ventricles (ventricular septum formation)
  4. the atria from the ventricles (heart valve formation)

-> this involves two actively growing masses of tissue : endocardial cushions and heart septae

46
Q

explain endocardial cushion growth

A

separates RA + V from LA + V to form L & R AV canals

47
Q

partitioning of primitive atrium into left and right atria

A

formation of septum primum & ostium primum
ostium secundum begins to form by apoptosis of part of septum primum
formation of septum secundum and formation of ostium secundum is complete , closure of ostium primum as septum primum meets the endocardial cushions
formation of foramen ovale is complete

48
Q

what is the role of the foramen ovale before birth

A

allows most of the blood to pass from the right atrium to the left atrium (non-functioning lung)
prevents passage of blood in the opposite direction

49
Q

what is the role of the foramen ovale after birth

A
normally closes (increased pressure in the LA due to increased pulmonary circulation)
septum primum fuses with septum secundum
fossa ovalis ( a depression in the interatrial septum) of adult heart is remnant of foetal foramen ovale
50
Q

what does non-closure of the PFO result in

A

common form of congenital Atrial Septal Defect (ASD) - “hole in the heart”

51
Q

explain partitioning of primitive ventricle

A

muscular ventricular septum forms. - opening is called interventricular foramen
aorticopulmonary septum divides bulbis cordis and truncus arteriosus into aorta and pulmonary trunk, bottom of spiral aorticopulmonary septum fuses with muscular ventricular septum and endocardial cushions to form membranous interventricular septum, closing interventricular foramen

52
Q

explain ventricular septal defect

A

most common type of CHD (congenital heart disease) - 25% of defects
can appear in any part of septum
small VSDs close spontaneously (30-50%)
membranous type of VSD is most common

53
Q

what week of pregnancy does partitioning of bulbus cordis(BC) and truncus arteriosus (TA) happen?

A

week5 - aorticopulmonary septum divides BC and TA into aorta and pulmonary trunk

54
Q

explain transposition of great vessels

A

common cause of cyanotic disease in newborn infants
associated with ASD and VSD
permit exchange of systemic and pulmonary circulation eg tetralogy of fallot
Cause - 1. failure of aorticopulmonary septum to take a spiral course
2. defective migration of neural crest cells to heart

55
Q

what develops from the ventricular wall (in terms of valves)

A

cusps, chordae tendinae and papillary muscles of the atrioventricular valves

56
Q

semilunar valves are formed from…

A

subendocardial valve tissue

57
Q

explain development of conducting system of the heart

A

early pacemakers are cardiomyocytes in primitive atrium and sinus venosus

clinical - cot death or sudden infant death syndrome (SIDS)
cause - abnormalities in conducting tissue

58
Q

in week 5 of pregnancy what develops in regard to conducting system of the heart

A

SA node (pacemaker)

59
Q

adult location of SA node

A

high in the RA near the entrance of SVC

60
Q

AV node and bundle

A

bundle of His - develops from cells of AV canal and sinus venosus

61
Q

aortic sac

A

aortic arches

62
Q

bulbis cordis

A

right ventricle

parts of outflow tracts

63
Q

primitive ventricle

A

left ventricle

64
Q

primitive atrium

A

parts of RA and LA

65
Q

sinus venosus

A

SVC & RA

66
Q

lateral plate mesoderm

A

mesenteries, lining of pleural, cardiac and abdominal cavities, and the major substance of the heart