Creado por Hannah Tribe
hace más de 10 años
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Formed from _________ layer around week __
It is the first organ to develop and function straight away. Why?
Development begins at ______ end of neural plate as 'heart __________'
Heart Primordium/Crescent becomes the _____ __________
Crescent contains 2 types of cells:
Growth of Crescent:
1. Medial expansion
3. Elongation of tube
(consisting of inner layer of endocardium, cardiac jelly then myocardium)
4. Looping of the tube -
Always coils to the _____ first (except in dextrocardia)
5. Addition of cells:
a) ___________ to separate outflow tract and form nerves
b) __________, originating from below tube, to form visceral ________, coronary vessels and other cell types
By _____ days, chambers are now visible, as parts of the tube have ballooned. Ventricles also now contain __________
6. Septation:
Forming the _______ between chambers
A) AV Septation to separate _____ from ___________
i) _________ cells undergo EMT (______ __________ _________)
and populate ______ ______ to form superior and inferior cushions
ii) 2 cushions fuse to leave tubes either side which become _______ between A + V. Surrounding cells become ________
Failure of AV septation results in AVSDs (_____________ ______ ______), common in babies with ______ __________
B) Atrial septation.
Begins with primary ______ _______, which elongates and fuses with ___ ______
Hole forms at top of septum called _______ ______ to allow __________________
The ______ _______ usually closes at birth. 10% of population have ________ FO, which can be lived with, due to pressure gradient keeping flap closed. Larger hole = _______ _______ type ASD (_____ _______ ______)
C) Ventricular septation:
_________ thicken and extend up to AV cushions.
Small piece of _______ joins septum to AV cushions as final part to fuse.
VSDs (______ ______ ______) can occur if ______ does not fuse. Called __________ VSD (75% cases).
Can also occur if there are holes in the _________. Called _______ VSD, but usually fixes itself at birth (25% cases)
D) OFT Septation (____________ ______)
Very complex - uses cushion system. Separates multiple _____ into 2 distinct ones: ________ ________ and ________ leaving the 2 atria. There are many possible defects with this stage.
TGA (________ of the ______ _________) causes ______ and ________ _______ to be connected to the wrong ventricles. Corrected with surgery.
TOF (______ __ _____) is a group of 4 defects commonly seen together:
1. VSD
2. ________ aorta, so both _______ and __________ blood enter it, with little going to the ______ _______.
3. ________ stenosis
4. RV __________
Corrected by early surgery.
Conduction tissue is derived from _________. Needs insulation.