790067
Description
Flashcards by Hannah Tribe, updated more than 1 year ago
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Created by Hannah Tribe
over 10 years ago
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| Question | Answer |
| Formed from _________ layer around week __ | Mesoderm, 3 |
| It is the first organ to develop and function straight away. Why? | Embryo is already large enough the diffusion alone is not sufficient to supply it with nutrients |
| Development begins at ______ end of neural plate as 'heart __________' | cranial, primordium |
| Heart Primordium/Crescent becomes the _____ __________ | Left ventricle |
| Crescent contains 2 types of cells: | 1. Endocardial cells to become endothelium 2. Myocytes for atria and ventricles, and to specialise into Purkinje fibres |
| Growth of Crescent: 1. Medial expansion | 2. 'Straight tube' stage: Heart tube attaches to developing arteries (set of arches) and cranial end, and developing veins at caudal end |
| 3. Elongation of tube (consisting of inner layer of endocardium, cardiac jelly then myocardium) | Cells added to outflow and inflow of tube so it grows, yet it is attached to blood vessels so coils as it expands. |
| 4. Looping of the tube - Always coils to the _____ first (except in dextrocardia) | RIGHT. This is controlled by complex human disease genes, so mutations = heart defects |
| 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 | Neural crest cells, Proepicardial organ, Pericardium |
| By _____ days, chambers are now visible, as parts of the tube have ballooned. Ventricles also now contain __________ | 28, Trabeculae |
| 6. Septation: Forming the _______ between chambers | Septums |
| A) AV Septation to separate _____ from ___________ | Atria from ventricles |
| i) _________ cells undergo EMT (______ __________ _________) and populate ______ ______ to form superior and inferior cushions | Endocardial, Epithelial mesenchymal transformation, cardiac jelly |
| ii) 2 cushions fuse to leave tubes either side which become _______ between A + V. Surrounding cells become ________ | Foramina, Valves |
| Failure of AV septation results in AVSDs (_____________ ______ ______), common in babies with ______ __________ | Atrioventricular septal defects, Down's Syndrome |
| B) Atrial septation. Begins with primary ______ _______, which elongates and fuses with ___ ______ | interatrial septum, AV cushions |
| Hole forms at top of septum called _______ ______ to allow __________________ | Foramen Ovale, blood flow between atria |
| 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 (_____ _______ ______) | Foramen ovale, persistent, ostium secundum, Atrial septal defect |
| C) Ventricular septation: _________ thicken and extend up to AV cushions. Small piece of _______ joins septum to AV cushions as final part to fuse. | Trabeculae, membrane |
| 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) | Ventricular Septal Defects, membrane, perimembranous, trabeculae, muscular |
| 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. | Outflow tract, vessels, pulmonary trunk, aorta |
| TGA (________ of the ______ _________) causes ______ and ________ _______ to be connected to the wrong ventricles. Corrected with surgery. | Transposition of the Great Arteries, aorta, pulmonary trunk |
| 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. | Tetralogy of Fallot, overriding, oxygenated, deoxygenated, pulmonary trunk, pulmonary, hyperplasia |
| Conduction tissue is derived from _________. Needs insulation. | Myocardium (NOT NERVES) |
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