Heart Embryology

• Heart Tube – formed from 2 vessels fusing together; develops muscle fibres in its wall and becomes pulsatile
• Differentiates into 4 parts. In cephalocaudal direction:
  1. Bulb
     • Upper part becomes the Truncus Arteriosus – divides to become the Aorta and Pulmonary Trunk
     • Lower part becomes most of the Right Ventricle
  2. Ventricle
     • Forms most of the Left Ventricle
  3. Atrium
     • Divides into 2
  4. Sinus Venosus
     • Becomes mostly absorbed into the Right Atrium
• Tube grows faster than the primitive pericardial cavity – it thus bends such that:
  • Bulb and Ventricle are in front of the Atrium and Sinus Venosus
  • Bulb twists to the right and Ventricle to the left