Embryology Flashcards Preview

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Flashcards in Embryology Deck (26)
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1
Q

Gastrulation is when the epiblast and hypoblast form: ectoderm, mesoderm and endoderm.
From what does the mesoderm layer form?

A

Epiblast

2
Q

From what layer of embryonic cells is the cardiogenic plate formed?

Until day about day 26, where exactly is this?

A

Mesderm

The visceral part of the splanchnic mesoderm (above the umbilical vesicle)

3
Q

Blood from which 2 supplying vessels flows caudally over the inflow tract?

A

Umbilical and omphalomesenteric veins

4
Q

Name the 3 layers of the cardiac tube.

A
  • epicardium
  • myocardiaium
  • endocardium (cardiac jelly inside)
5
Q

What divides the left and right ventricles in embryo?

A

Sulcus interventricularis

6
Q

Day 25 lateral plate mesoderm splits

  • What does the visceral layer form with the adjacent endoderm?
  • What does the parietal layer form with the adjacent ectoderm?
A
  • splanchnopleura

- somatopleura

7
Q

When does the head fold occur, causing the previously caudal outflow tract to lie cranially to the inflow tract through a 180 rotation.

A

Day 25-26

8
Q

What do the 2 endocardial tubes form when they migrate and fuse together?

A

A Single primitive heart tube

9
Q

Name the 5 embryonic structures that arise from the primitive heart tube, cranial to caudal.

A
  • truncus arteriosus
  • bulbus cordis
  • privitive ventricle
  • primitive atria
  • sinus venosus
10
Q

What do the following develop into:

  • truncus arteriosus
  • bulbus cordis
  • privitive ventricle
  • primitive atria
  • sinus venosus
A

-truncus arteriosus - ascending aorta and pulmonary trunk

  • bulbus cordis - right ventricle
  • privitive ventricle - left ventricle
  • primitive atria - anterior portions of auricles and both atria
  • sinus venosus - post R atrium, SAN and coronary sinus
11
Q

What are CNCCs and what do they contribute to?

A

Cardiac Neural Crest Cells

Contribute to Smooth Muscle cells within aortic and pulmonary arteries

12
Q

The atrioventricular septation in the horizontal plane if formed from what?

A

AV cushions

13
Q

Intra-atrial septatation is by…

..forming….

A

Primary Septum grows down to fuse with AV cushions, the trailing edge breaks down forming the foramen ovale

The septum secundum grows alongside this to form a flap valve over the foramen ovale

14
Q

Interventricular septation occurs by…

A

AV septum grows up to meet and fuse with AV cushions to completely divide the L/R Ventricles

15
Q

How is the AV cushion formed?

A

From cardiac jelly secreted by myocardium,

Endocardial cells undergo epithelial-mesenchymal transition and populate the jelly to form a cushion

16
Q

Name 3 Atrial Septal Defects

A
  • Persistant foramen ovale
  • Ostium primum defect - primary septum doesnt reach AV cushions
  • Ostium secundum defect
17
Q

Why are ASDs acyanotic?

A

Inappropriate shunting of blood is only from left side to right side (as higher pressure in left)

18
Q

Give two types of Ventricular Septal Defects.

A

Perimembranous - doesnt meet cushions

Muscular - hole in the lower muscular part of septum

19
Q

Which aortic arch arteries persist in forming the adult structures?

A

3, 4 and 6

20
Q

The ductus arteriosus bypasses circulation to the lungs.

What is it called in the adult?

A

Ligamentum arteriosum

21
Q

2 OFT-outflow tract defects.

A
  • common truncus

- aortic/pulmonary stenosis die to unequal division of OFT

22
Q

What is the condition TGA-Transposition of the Great Arteries?

A

RV connected to aorta,
LV connected to pulmonary trunk

This is cyanotic

23
Q

What are the features of a Tetralogy of Fallot

A
  • large VSD
  • pulmonary stenosis
  • RV hypertrophy
  • overriding aorta (receives input from both L and R ventricles)
24
Q

Why may a Tetralogy of Fallot child appear “blue”?

A

Right to Left shunt is cyanotic

25
Q

TAPVC - Total Anomalous Pulmonary Venous Connection shunts blood in what direction?

A

Right to Left (cyanotic)

26
Q

Why are defects causing holes in septum usually acyanotic?

A

Because L pressure is higher so shunts blood to right side