Final Embryo - Heart Development Flashcards Preview

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Flashcards in Final Embryo - Heart Development Deck (64)
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1
Q

This is when splanchnic mesoderm cells cluster together to form a solid horseshoe-shaped cord of endothelial cells

A

vasculogenesis

2
Q

Where does the horseshoe shaped endothelial cord form

A

within cardiac mesoderm

3
Q

True or False

The cardiac system is the last system that becomes functioning in an embryo

A

False; it is the first functioning system

4
Q

When does the horseshoe shaped endothelial cord hollow out

A

in the 4th week

5
Q

How does the horseshoe shaped endothelial cord form a single heart tube

A

via the folding of the lateral sides of the endothelial tube in ventrally and medially approaching each other at the midline to fuse

6
Q

Upon lateral folding to form the heart tube, what else fuses

A

paired dorsal aortae

7
Q

This repositions the developing heart and pericardial cavity

A

head folding

8
Q

prior to head folding, the heart is located where

A

rostral to oropharyngeal membrane

ventral to pericardial cavity

9
Q

post head folding, the heart is located where

A

caudal to oropharyngeal membrane
dorsal to pericardial cavity
ventral to foregut
rostral to spetum transversum (diaphragm)

10
Q

This acts like a “hinge” in head folding to reposition the heart

A

oropharyngeal membrane

11
Q

As the dorsal mesocardium degenerates (day 22), what forms

A

transverse pericardial sinus

space behind the aorta and pulmonary trunk

12
Q

What are the layers of the primitive heart tube from deep to superficial

A
endothelium
cardiac jelly
myocardium
epicardium
pericardial cavity
parietal pericardium
13
Q

All of the layers of the primitive heart tube are derived from what

A

splanchnic mesoderm

14
Q

At what day does the heart begin to beat

A

Day 22 or 23

15
Q

What are the dilations of the primordial heart tube

A
sinus venosus
primordial atrium
primordial ventricle
conus cordis
truncus arteriosus
16
Q

The sinus venous forms what structures in adults

A

coronary sinus

sinus venarum

17
Q

The primordial atrium forms what structures in adults

A

right and left auricles

portions of the atria

18
Q

The primordial ventricle forms what structure in adults

A

left ventricle

19
Q

The conus cordis forms what structures in adults

A

outflow tract of the ventricles

caudal (proximal) portion of forms right ventricle

20
Q

The truncus arterioles forms what structures in adults

A

pulmonary trunk

aorta

21
Q

What to primitive structures form the bulbs cordis

A

truncus arteriosus

conus cordis

22
Q

This is between the primordial atrium and primordial ventricle

A

atrioventricular sulcus

atrioventricular canal

23
Q

This is between the primordial ventricle and conus cordis

A

bulboventricular sulcus

primary interventricular foramen

24
Q

Where does the blood flow after the bulbs cordis

A

aortic sac then pharyngeal arch arteries

25
Q

When does the formation of the cardiac loop/heart folding takes place when

A

Days 22-28

26
Q

As the heart fold, which direction does it move

A

its cranial end will shift ventrally, caudally and to the right
its caudal end will shift dorsally and superiorly

27
Q

What is the blood circulation through the primordial heart

A
sinus venosus
primordial atrium
atrioventricular canal
left (primordial) ventricle
interventricular foramen
right ventricle
conus cordis
truncus arteriosus
aortic sac
pharyngeal aa.
dorsal aortae
28
Q

Partioning of he primordial heart takes place when

A

Days 27-37

29
Q

In partitioning the atrioventricular canal endothelial cells near the AV junction do what

A

revert to mesenchymal state, invade the underlying cardiac jelly, and proliferate

30
Q

What does the endothelial cells near the AV junction cause

A

it cause the endocardium to bulge out into the AV canal from its dorsal and ventral walls

31
Q

The dorsal and ventral endocardial walls develop and fuse together forming what

A

atrioventricular septum that divide the atrioventricular canal into right and left AV canals

32
Q

Is the portioned AV canal completely sealed off?

A

No

33
Q

Partioning of the primordial atrium involved what

A

forming two septa that will fuse together to from the interatrial septum

34
Q

What are the two septa of the intertribal septum

A
septum primum (first)
septum secundum (second)
35
Q

This develops from the roof of the primordial atrium as the thin, moon-shaped membrane

A

septum primum

36
Q

This grows inferiorly to fuse with the endocardial cushions

A

spetum primun

37
Q

The opening between the inferior edge of the septum primun and the endocardial cushions is what

A

foramen primun

38
Q

As the septum primum fuses with the endocardial cushions and the foramen primum closes, what forms

A

holes in the center of the septum primun via apoptosis

forming foramen secundum

39
Q

As the foramen secundum is formed, what beings to develop to the right

A

septum secundum

40
Q

The septam secundum grows inferiorly and develops an opening called what

A

foramen ovale (oval foramen)

41
Q

Where does blood flow via the foramen ovale and foramen secundum

A

blood now passed from right to left atrium

42
Q

After birth, what happens to the foramen ovale

A

it closes off and there is no blood flow between atria

43
Q

What forms the valve of the foramen ovale

A

the septum primum; the cranial portion degenerates

44
Q

After birth, what happens to the valve of the foramen ovale

A

The blood pressure of the left atrium exceeds the right atrium which pushed the valve closed and they fuse which closes of the foramen

45
Q

What does the closing of the foramen oval create

A

fossa ovalis; a depression in the wall of the right atrium

46
Q

The muscular portion of the IV septum grows where

A

cranially toward the AV septum, but does not fuse with it

47
Q

The opening between the right and left ventricles is what

A

the interventricular foramen

48
Q

The membranous portion of the IV septum is derived from what

A

the mesenchyme of the endocardial cushion tissue

49
Q

This develops at different orientations through the length of the conus cordis and truncus arteriosus

A

endocardial cushions

50
Q

The endocardial cushions of the bulbus cordis fuse with each other forming what

A

a twisting aorticopulmonary septum that divides the outflow tract into pulmonary trunk and aorta

51
Q

What is the most common congenital heart defect

A

ventricular septal defect

52
Q

What is a ventricular septal defect

A

failure of IV septum to completely form

53
Q

What is the anatomical basis for a ventricular septal defect

A

in most cases (80%) the membranous portion of the septum fails to form, but can also be the muscular portion

54
Q

What are some of the main transpositions of great vessels

A

the aorticopulmonary septum grows straight instead of spiraling
aorta arises from right ventricle
pulmonary trunk arises from left ventricle

55
Q

What is the tetralogy of fallot

A

interventricular septal defect
hypertrophy of right ventricle
overring aorta
pulmonary stenosis

56
Q

Aorticopulmonary septum divides what

A

outflow tract unequally, resulting in stenosis of pulmonary trunk and an overriding aorta

57
Q

What 3 pairs veins drain into the sinus venosus

A

vitelline (from yolk sac)
umbilical (deoxygenated blood)
common cardinal (body of embryo)

58
Q

Originally, the sinus venous opens where

A

directly into the central dorsal wall of the primordial atrium

59
Q

Blood flow from the heart gradually shifts to the right side due to what

A

remodeling of the vitelline, umbilical, and anterior cardinal veins

60
Q

What is the result of the blood flow remodeling to the right

A

the right horn of the sinus venosus becomes larger than the left

61
Q

The right horn of the sinus venosus becomes what

A

smooth walled portion of the right atrium (sinus venarum)

62
Q

The left horn of the sinus venosus becomes what

A

the coronary sinus that drains into the right atrium

63
Q

As the heart grows, the primordial pulmonary veins and portions of its branches are incorporated where

A

into the dorsal aspect of the heart, forming the smooth-walled portion of the left atrium

64
Q

The aortic sac becomes what in adults

A

ascending aorta