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The heart is formed between ____ & ____ weeks of gestational age.
Week 3 (early), the heart is composed or ______ endocardial ________.
The cardiac tube consists of ____________ ____________ with core cardiac ____________.
Endocardium and cardiac jelly forms ______________ ________________.
Outer myocardial mantle becomes _________________ heart wall.
The 5 primitive areas of the heart are:
- 1. sinus venosus
- 2. common atria
- 3. common ventricle
- 4. conus cordis (future LV & RVOT's)
- 5. Truncus Arteriosus (roots AO & pulmonary arteries)
What is looping?
When does it occur?
Looping of heart tubes as they grow at a faster rate than the pericardium. Dextro=Rt=normal. Levo=left=malposition of vent or great vessels
Looping starts at day 24
Heart begins to beat at day _________.
Circulation of heart begins at day _____to____.
Sinus venosus - Lt horn becomes:
oblique vein of LA & coronary sinus
Sinus venosus Rt horn becomes:
Part of RA, IVC, SVC
What is the most posterior part of embryological heart
sinus venosus left horn
IAS forms between _____ & _____ day.
There are 3 events of IAS formation. Explain
- 1. Septum Primum (divides atrium to Lt & Rt sides)
- 2. Septum Secundum (forms superior portion of RA adjacent to septum primum; oval shaped opening persists
- 3. Fossa Ovalis (early remnants of sinus venosus tissue found @ jxn of IVC & SVC with RA)
Expain the events of Ventricular Septal Formation: (3)
- 1. Lateral aspect expanding faster than medial = med invagnation=gradually fuses to form a portion of IVS. Small opening @ level AV valves permits con't communication.
- 2. Muscular IVS forms passively by expansion of ventricle (27th day)
- 3. MMB IVS forms actively by growth of endocardial cushion (b/c it has a bigger job)
Explain the events of AV Canal Formation: (3)
- 1. 30-40 days - 4 mesenchymal swellings appear.
- 2. 2 endocardial cushions = septal TV leaflet & AMVL and a portion of inflow perimmb IVS
- 3. 2 lateral cushions = ATVL, PTVS, PMVL
The events of outflow tract formation are: (3)
- 1. Conus Cordis divides outflow tract into Rt & Lt.
- 2. 2 swellings in truncus arteriosus form septum dividing into AO and pulmonic and twist around each other as they expand therefore the spiral relationship(begins at distal end from truncus -->conus cordis
- 3. Tubercles on main truncus swelling responsible for formation of AO and pulmonic valves
3rd set of AO arches becomes the _____________________?
CCA & ICA
4th set AO arches becomes _____________________.
6th set AO arches becomes ___________________________.
Rt & Lt Pulmonary Arteries
The distal portion of 6th AO arch remains in connection to arterial system via ______________ ______________.
ductus arteriosus (pulmonary to systemic shunt)
Fetal Circulation Review: O2 blood from placenta returns IVC and shunts across the ___________.
3 weeks =
- 5-6 part primitive cardiac tube
- carciac loop begins
- all 4 chambers are complete
What is the cardiogenic region?
Horseshoe shaped region b/f endocardial cushion done forming valves.
What is the septum primum in an adult called?
Right atrium - atrial fold - helps direct O2 IVC blood across IAS to fetal circulation =