Development of Cardiovascular System Flashcards

1
Q

Stages of Embryonic heart development

A
Linear Heart Tube Formation
-->
Formation of the cardiac loop
-->
Heart septation
-->
Cavitation of ventricle
Formation of valves & great vessels
-->
4-chambered heart
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2
Q

Describe the regions found anteriorly on the linear heart tube at approx day 22 of embryonic development

A

Think of the bottom as the inflow part and the top as the outflow part

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3
Q

Dorsal Mesocardium

A

Structure that keeps the linear heart tube attaches to the body of the embryo

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4
Q

Describe the lining of the heart tube

A

Endocardial lining with a myocardial layer

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5
Q

What does the truncus arteriosus form in an adult heart

A

Most of the proximal aorta and pulmonary trunk

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6
Q

What does the bulbus cordis form in an adult heart

A

Right Ventricle

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7
Q

What does the ventricle region of the heart tube form in an adult heart

A

Left Ventricle

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8
Q

What does the atrium region of the heart tube form in an adult heart

A

Trabeculated portions of RA & LA

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9
Q

What does the left sinus venosus horn form in an adult heart

A

Coronary Sinus

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10
Q

What does the right sinus venosus horn form in an adult heart

A

Smooth wall of right atrium

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11
Q

Conus Cordis

A

Be vaguely aware of this structure as being part of the outflow tract

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12
Q

Which parts of the heart tube grow the fastest and what does this lead to

A

Ventricles and bulbus cordis

Leads to the heart bending in a rightward direction, leading to the atrium and sinus venosus moving cranially and dorsally when originally being caudal to the ventricle

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13
Q

When the cardiac loop is formed, describe the septation of the heart

A

At that point there is no septation and the right/left atria and right/left ventricles are continuous with one another

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14
Q

Name the 3 Endocardial Cushions and their positions

A

Cushions in AV region

In outflow region - conal cushions and truncal cushions (sometimes outflow cushions referred to as ridges)

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15
Q

What do the endocardial cushions look like

A

They are localised swellings in the outflow tract and AV canal full of matrix

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16
Q

What happens to the endocardial cushions as the embryo developsg

A

They thicken and protrude into the lumen

Cells from endothelial lining activate and migrate into endocardial cushion matrix and make it cellular

17
Q

Role of endocardial cushions in embryonic development

A

They play a major role in normal heart septation and normal cardiac valve formation

18
Q

Describe the formation of the foramen secondum

A

A little septum primum grows down into the foramen primum. Apoptosis leads to a bunch of perforations in the septum primum as it forms - the perforations then re-fuse and leave two openings; foramen primum above the endocardial cushion and foramen secondum between the strip of joint cells and septum primum

19
Q

Describe the events leading to formation of valve of foramen ovale after foramen secundum formation

A

The strip of cells that have joined fuse together with the endocardial cushions, leaving behind only the foramen secundum

Simultaneously a developing septum secundum forms adjacent to the previous septum which grows down, eventually overlapping with the primum

This leaves the valve of the foramen ovale between RA and LA in an embryo made by the septum primum

20
Q

Describe the septation of the primitive ventricle

A

Myoblast proliferation leads to cells growing up from the ventricular floor towards the endocardial cushions in the AV canal

By 6 weeks there is still an interventricular foramen; it is closed by a membranous portion though and forms a septum

21
Q

How do AV valves form

A

Endocardial cushions undergo modification and restructuring to give rise to the cusps of valves

(Diagram gives a lot of extra info, all you really need to know is the text above)

22
Q

How do the great vessels form

A

Tube coming out of the heart

23
Q

What shape do the ridges in the outflow tract make (Truncal ridge and bulbar ridge)

A

They form a continuous spiral-like shape as they change from being lateral and at other times being dorsal and ventral

24
Q

What is the result of the truncal and bulbar ridge spiral formation

A

The ridges join along the spiral to form a septum. This separates the pulmonary trunk and proximal part of the aorta into two different vessels that twist around one another

25
Q

What tissue forms the semilunar valves

A

These valves are formed from the outflow endocardial cushions that specialise into valves

26
Q

How do the SVC and IVC form

A

They are derived from primordial veins that undergo a series of changes during development, leading to their remodelling and incorporation into these new great vessels

27
Q

How does the Pulmonary Vein form

A

Most of the smooth wall of the LA is derived from the primordial pulmonary vein and its branches; as the atrium expands, more PV is uncorporated until ultimately 4 are present

28
Q

Compare pre and post natal circulation in the heart

A

The ductus arteriosis and oval foramen are the main differences to be aware of

Also just know that lungs here give back deoxygenated blood in prenatal circulation as those cells use the blood

29
Q

What is the role of the ductus arteriosus

A

It takes blood straight to the aorta to go around the body such that the prenate’s lungs are not overloaded

30
Q

Ligamentum arteriosum

A

Ligament present in healthy adults that is a remnant of the ductus arteriosus

31
Q

What leads to the closure of the foramen ovale

A

Changes in pressure at birth as the baby breathes

Over the coming days and weeks, the cells fuse and entirely shut the foramen ovale

32
Q

Is the foramen ovale prone to birth defects

A

Yes ffs yes it is

33
Q

Have a vague awareness of cardiac development time

A
34
Q

Ostium Secundum ASD

A

Atrial Septum Defect

A hole is formed in the centre of the atrial septum

35
Q

Pathophysiology of Atrial Septal Defects

A

Enlarged RA, RV and/or PA

Also some considerable intracardiac shunting may occur

36
Q

Ventricular Septal Defect and frequency

A

Most common CHD (approx 25%)

Can involve the muscular or membranous part of ventricular septum (usually involves membranous part failing normal development)

Can treat itself