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Atrial septation in the rat. II. An electron microscopic study
Journal of Submicroscopic Cytology
|April 1, 1986
Summary
Embryonic rat heart development involves atrial septation, where the septum primum divides the chamber. Electron microscopy reveals endocardial cells forming openings for blood flow during this crucial cardiac septation process.
Area of Science:
- Developmental biology
- Cardiovascular embryology
- Cell biology
Background:
- Atrial septation is critical for fetal circulation.
- Understanding septation mechanisms aids in diagnosing congenital heart defects.
Purpose of the Study:
- To investigate atrial septation in embryonic rat hearts.
- To elucidate the cellular mechanisms of interatrial communication formation.
Main Methods:
- Scanning electron microscopy (SEM) for structural analysis.
- Transmission electron microscopy (TEM) for ultrastructural details.
- Embryonic rat heart development from day 12.50 to 16.50.
Main Results:
- Septum primum formation observed by day 12.50, initiating atrial division.
- Foramen secundum develops via transseptal communications formed by endocardial cell processes.
- Dilated rough endoplasmic reticulum with a honeycomb appearance noted in endocardial cells.
- A second septum (septum secundum) forms by day 16.50.
Conclusions:
- Atrial septation involves dynamic cellular processes, not cell death.
- Endocardial cell extensions and endoplasmic reticulum changes are key to foramen formation.
- SEM and TEM provide detailed insights into cardiac septation mechanisms.
