Session 3 Lectures Flashcards

1
Q

Which week does the embryo fold & does the position of carcinogenic field change?

A

In week 4 of embryonic period (embryonic period = week 3-8)

Yes the position changes

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2
Q

Suggest a reason why congenital heart defects are one of the most common defects

A

There are different circulatory needs of the fetus and newborn baby - need to be able to create both and switch over immediately after birth

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3
Q

What is at the inlet of the primitive heart tube?

A

Sinus venous and primitive atrium

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4
Q

What is at the outlet of the primitive heart tube?

A

Aortic roots

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5
Q

Suggest why cardiac looping takes place

A

To maximise the amount of space the heart has within the pericardial sac

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6
Q

What is the primitive heart tube composed of?

A

Fusion of 2 endocardial tubes

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7
Q

What does right atrium develop from?

A

Most of the primitive atrium and sinus venosus (inlet of heart tube)

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8
Q

What does left atrium develop from? And why is it smoother?

A

A small portion of primitive atrium and proximal parts of the pulmonary veins
These are made of smooth muscle so left atrium is smoother

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9
Q

In the fetus the lungs don’t work - where does oxygenation and removal of CO2 take place?

A

At the placenta

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10
Q

When oxygenated blood enters the umbilical vein what does it reach first and how does it bypass this?

A

It reaches the liver first
Shunt of blood to go directly to inferior vena cava
This shunt is called the ductus venosus

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11
Q

In the fetus oxygenated blood travelling from inferior vena cava reaches right atrium and is shunted across to pulmonary trunk. What is this shunt called?
Does some blood go into right ventricle first?

A

Foramen ovale

Yes some does reach right ventricle so that this muscle properly develops

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12
Q

In the fetus blood eventually reaches pulmonary trunk and is shunted to aorta as it is already oxygenated. What is this shunt called?

A

Ductus arteriosus

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13
Q

What nerve becomes hooked around the pulmonary trunk and aorta in development?

A

The left recurrent laryngeal nerve

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14
Q

What does PDA stand for and what is the condition?

A

Patent ductus arteriosus
When the ductus arteriosus doesn’t close after birth - blood is now shunted from aorta to pulmonary trunk (down pressure gradient)

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15
Q

What are the 2 septums called? What are the 2 hole called that form (1 in each)?

A

Septum primum and septum secundum

Ostium secundum and foramen ovale

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16
Q

What happens to the foramen ovale in healthy newborns?

A

It is closed by the pressure of the left atrium (forcing the septum primum and septum secundum close together)

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17
Q

What is hypoplastic left heart syndrome?

A

The left ventricle and ascending aorta fail to develop properly
A patent foreman ovale or atrial septum defect is also present and blood supply to systemic circulation is via a patent ductus arteriosus

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18
Q

What are the 2 components of ventricular septum?

A

Muscular

Membranous

19
Q

What is the primary interventricular foramen?

A

The small gap left after muscular portion of ventricular septum has formed

20
Q

How is the primary interventricular foramen closed?

A

The membranous portion of the interventricular septum is formed by connective tissue and closes the gap

21
Q

In the fetus what does the blood flow out from?

A

The truncus arteriosus

22
Q

What are the 4 symptoms of tetralogy of fallot?

A

1) ventricular septal defect
2) Overriding aorta
3) Pulmonary stenosis
4) Can lead to right ventricular hypertrophy

23
Q

What are neural crest cells derived from and what do they contribute to creation of?
What can damage them in pregnancy?

A

They are derived from neurectoderm
They contribute to creation of endocardial cushions
They can be damaged in pregnancy if the mother drinks alcohol

24
Q

What is the oxygen saturation levels of oxygenated blood going through heart and deoxygenated blood going through heart?

A

100% when oxygenated

67% when deoxygenated

25
Q

What is the pressure (systolic and diastolic) in mm/hg in the left ventricle and right ventricle?

A
Left = 80/4
Right = 25/3

The systolic pressure is the pressure needed to open the aortic and pulmonary valves

26
Q

What is cyanosis?

A

Presence of deoxygenated haemoglobin in arterial circulation

27
Q

What happens in a left to right shunt?

A

Blood travels from left ventricle back to the lungs instead of the body

28
Q

What happens in a right to left shunt?

A

Blood travels from right ventricle to circulate around body without being oxygenated by lungs

29
Q

Describe an atrial septal defect

- describe which direction blood flows and what it eventually leads to

A
Hole in septum separating two atrium
Blood flows from left to right down pressure gradient (so no mixing of deoxygenated blood with oxygenated travelling around body)
Leads to increased pulmonary blood flow
Increased in RV volume
Leads to right sided heart failure
30
Q

Where is the most common location for an atrial septal defect?

A

In the ostium secundum

31
Q

Why is a patent foreman ovale normally clinically silent?

A

Because the pressure of the left atrium keeps the flap closed

32
Q

Describe a ventricular septal defect

State which way blood flows and what it leads to

A
Abnormal opening in ventricular septum 
Blood flows from left to right down pressure gradient 
Leads to LV volume increase 
Pulmonary venous congestion 
Pulmonary hypertension
33
Q

Describe a patent ductus arteriosis
What is its purpose in the fetus?
Why does it normally close after birth?
Which direction does blood flow if it fails to close after birth?

A

The ductus arteriosis is a vessel in the fetus that shines blood from pulmonary artery to aorta bypassing lungs
It should close after birth as pressure in pulmonary artery drops following perfusion of lungs = patent ductus arteriosis is when it doesn’t.
Blood flows from aorta to pulmonary artery after birth (high to low pressure)

34
Q

What is eisenmonger syndrome?

A

Any untreated congenital heart defect that leads to pulmonary hypertension and cyanosis
Blood flows from left to right down pressure gradient

35
Q

Describe coarction of the aorta

  • what can it lead to?
  • to where is blood flow reduced?
  • to where does blood flow remain the same and why?
A

It is a narrowing of the aortic lumen which increases afterload on LV and can lead to LV hypertrophy
It affects blood flow to body (except head and upper limbs as the vessels leading here usually appear after coarctation)

36
Q

In which region of the aorta is coarction of the aorta?

What vessel appeared at this location in the fetus?

A

In the ligamentum arteriosum

It was the former ductus arteriosus in fetus (bypassing blood away from lungs from pulmonary arteries to aorta)

37
Q

In coarctation of the aorta what will the femoral pulses be like in either side of the body?

A

The femoral pulse only on the left will be weaker and there may be a delay in the pulse compared to the right

38
Q

What are the the four anomalies in tetralogy of fallot?

A

1) Pulmonary stenosis
2) ventricular septal defect
3) Right ventricular hypertrophy
4) Overiding aorta

39
Q

Is tetralogy of fallot a cyanosis defect and why?

A

Yes - there is mixing of deoxygenated blood with oxygenated blood leaving the aorta
Increased pressure in the right ventricle (due to pulmonary stenosis and overiding aorta) means blood travels right to left

40
Q

What is tricuspid atresia?

By what method will blood be oxygenated?

A

Lack of development of the tricuspid valve
There has to be a complete shunt of blood from right to left
Blood oxygenated via a patent ductus arteriosis or a ventricular septal defect (allowing left to right movement of blood to lungs)

41
Q

In transposition of the great arteries - which vessels are connected to which ventricle?

A

Right ventricle to aorta

Left ventricle to pulmonary artery

42
Q

What is pulmonary atresia?

A

No right ventricle outlet
Right to L atrial shunt of entire venous return and blood flows to lungs via a patent ductus arteriosis (blood flows from aorta to pulmonary artery)

43
Q

Name 3 acyanotic defects

A
Atrial septal defect
ventricular septal defect
patent foreman ovale
coarction of the aorta
patent ductus arteriosis
44
Q

Name 3 cyanotic defects

A

Tetralogy of fallot
tricuspid atresia
transposition of the great arteries hypoplastic left heart