CV Embryo

  1. Truncus Arteriosus
    Ascending Aorta and Pulmonary Trunk
  2. Bulbus Cordis
    • Smooth Parts (outflow tracts) of Ventricles
    • Right → Conus Arteriosus
    • Left → Aortic Vestibule
  3. Endocardial Cushion
    Atrial Septum, Membranous Intraventricular Septum, AV & Semilunar Valces
  4. Primitive Atrium
    Trabeculated parts of the atria
  5. Primitive Ventricle
    Trabeculated parts of the ventricles
  6. Primitive Pulmonary Vein
    Smooth part of the right atrium (sinus venarum)
  7. Right Common cardinal vein and Right Anterior Cardinal Vein
    Superior Vena Cava
  8. Defect in left-right dynein
    L/R Assymetry that can lead to dextrocardia (seen in Kartagener Syndrome - primary ciliary dyskinesia)
  9. Cardiac Looping (4 stages)
    • Early looping - inherent
    • convergence - alignment of atrioventricular and conoventricular canal
    • wedging - conoventricular canal between tricuspid and mitral valves
    • Repositioning - atrioventricular canal straddles L/R Ventricles
  10. Why does the heart tube loop?
    establish left-right polarity
  11. When does cardiac looping begin?
    Week 4 of gestation
  12. Describe the process of Atrial Septation
    • 1. Septum Primum grows towards endocardial cusions - foramen primum is formed
    • 2. Foramen secundum opens up in septum primum (apoptosis) and septum primum continues to grow closing foramen primum
    • 3. Septum secundum develops
    • 4. Septum secundum expands and covers most of foramen secundum -residual opening is foramen ovale
    • 5. Septums fuse to form the atrial septum
    • 6. Foramen ovale usually closes at birth due to increased LA pressure
  13. Patent Foramen Ovale
    • failure of septum primum and secundum to fuse after birth
    • most left untreated but can lead to a paradoxical embolus
  14. Ventricular Septation
    • 1. Muscular Interventricular septum forms with an opening called the interventricular foramen
    • 2. Aorticopulmonary septum rotates and fuses with muscular ventricular septum to form the membranous interventricular septum closing the interventricular foramen
    • 3. growth of endocardial cushions separates the atria from the ventricles and contributes to both atrial septation and membranous portion of the interventricular septum
  15. VSD
    most common cardiac congenital anomaly (25%) and usually occurs in the membranous portion of the septum
  16. Outflow Tract Formation
    Neural crest and endocardial cell migrations → truncal and bulbar ridges that spiral and fuse to form the aorticopulmonary septum → aorta and pulmonary trunk
  17. Conotruncal abnormalities associated with a failure of neural crest migration
    • Transposition of the Great Vessels
    • Tetralogy of Fallot
    • Persistent Truncus Arteriosus
  18. From what are the semilunar valves derived?
    endocardial cushions of the outflow tract
  19. From what are the AV Valves derived?
    fused endocardial cushions of the AV canal
  20. Valvular Anomaly General Categories
    • Stenosis
    • Regurgitation
    • Atretic
    • Displased - Ebstein
  21. What type of tissue does the heart tube originate from?
    • Lateral Plate Mesoderm splits into somatic and splanchnic
    • Splanchnic becomes the pericardial cavity
    • Precardiac mesoderm distributes into the splanchnic mesoderm which become heart forming regions that fuse with lateral folding at the midline
  22. Allantosis
    Urachus →Median Umbilical Ligament
  23. Ductus Arteriosus
    Ligamentum Arteriosum
  24. Ductus Venosus
    Ligamentum Venosum
  25. Foramen Ovale
    Fossa Ovalis
  26. Notochord
    Nucleus Pulposus
  27. Umbilical Arteries
    Medial Umbilical Ligaments
  28. Umbilical Vein
    Ligamentum Teres (contained in the falciform ligament)
  29. Role of the Ductus Venosus in Fetal Circulation
    • shunt oxygenated blood from the umbilical vein to the IVC bypassing the liver
    • Mixing will then occur at the IVC
  30. Role of the Foramen Ovale in Fetal Circulation
    • Path for oxygenated blood from the IVC to enter the LA and then be pumped to the rest of the body through the aorta
    • Some mixing may occur in the RA but not a lot
  31. Role of the Ductus Arteriosus in Fetal Circulation
    • Deoxygenated blood from the SVC moves through the tricuspid valve to the RV and then through the Pulmonary Trunk.
    • Blood then passes through the PDA to the Aorta after the branches going to the head and upper body
    • Reserves the best oxygenation for the brain and then mixing occurs in the aorta
  32. What happens when the newborn breathes?
    • Upon inhalation the lungs expand decreasing the resistance in the lungs
    • Increased pressure in the pulmonary arteries then allows blood to circulate through the lungs
    • Increased Pressure in the LA due to the return of blood through the pulmonary veins slams the foramen ovale closed 
    • increased O2 and decreased PGs (from separation of the placenta) encourage closing of the PDA
  33. How do you keep the Ductus Arteriosus Patent?
    PGE1 and PGE2
  34. How do you encourage closure of a PDA
Card Set
CV Embryo