Heart Derivatives Embryology – Video Tutorial

Embryonic Heart:

In human embryos the heart begins to beat at about 22-23 days, with blood flow beginning in the 4th week. The heart is therefore one of the earliest differentiating and functioning organs.

The heart begins very early in mesoderm within the trilaminar embryonic disc. The heart forms initially in the embryonic disc as a simple paired tube inside the forming pericardial cavity, which when the disc folds, gets carried into the correct anatomical position in the chest cavity.

A key aspect of heart development is the septation of the heart into separate chambers. As the embryonic/fetal circulation is different to the neonatal circulation (lung/pulmonary activation), several defects of heart septation may only become apparent on this transition. One septal “defect” occurs in us all, the foramen ovale (between the 2 atria) which in general closes in the neonate over time.

This video tutorial on Heart Derivatives has been provided by: 100lyric

Heart Derivatives:

Here is a list of terms for parts of the embyronic cardiovascular system, followed by notes about what these bits and pieces turn into in adults.

  • Sinus venosus (R horn): smooth part of right atrium (sinus venarum) and the “valve” of the superior vena cava. The sino-atrial node.
  • Sinus venosus (L horn): coronary sinus, valve of coronary sinus
  • Valve of sinus venosus (R): border of smooth part of right atrium (crista terminalis)
  • Valve of sinus venosus (L): part of atrial septum
  • Common atrium: rough part of right and left atria and the auricles
  • Embryonic pulmonary vein: large part of the left atrial wall
  • Septum primum: left side of the atrial septum
  • Septum secundum: right side of the atrial septum
  • Foramen secundum: dimple in the atrial septum seen from left side (fossa ovalis, ok)
  • Foramen ovale: fossa ovalis
  • Endocardial cushions: parts of the atrioventricular wall, mitral, and tricuspid valves
  • Endocardial cushions: membraneous part of ventricular septum, part of arterial trunk
  • Bulbus cordis: trabeculated part of R ventricle and aortic vestibule of L ventricle
  • Truncus arteriosus: ascending (ventral) aorta and pulmonary artery
  • Common ventricle: parts of the right and left ventricle

Arterial System:

  • Aortic sac (R and L sides of sac): brachiocephalic artery (right) and part of the ascending aorta (left), large parts of common carotid arteries
  • 1st aortic arch (R and L): part of the maxillary artery and external carotid arteries
  • 2nd aortic arch (R and L): part of the hyoid and stapedial arteries, part of external carotids
  • 3rd aortic arch (R and L): part of common carotids and first part of the internal carotids
  • 4th aortic arch (R): small proximal part of the right subclavian artery
  • 4th aortic arch (L): small part of arch of the aorta just proximal to the left subclavian artery
  • 6th aortic arch (R): proximal part of right pulmonary artery
  • 6th aortic arch (L=ductus): proximal left pulmonary artery and and ligamentum arteriosum
  • Ductus arteriosus: ligamentum arteriosum
  • Dorsal aorta (R and L): part of right subclavian, descending aorta below left subclavian
  • Unpaired ventral (or vitelline) arteries: celiac, superior mesenteric, and inferior mesenteric arteries
  • Paired dorsal segmental arteries: intercostal arteries and vertebral arteries
  • Umbilical arteries: internal iliac, superior vescial arteries, medial umbilical ligaments

Venous System:

  • Ductus venosus: ligamentum venosum
  • Umbilical vein (L): round ligament (ligamentum teres)
  • Vitelline vein (R): superior mesenteric vein and the inferior vena cava
  • Vitelline vein (L): most of the portal vein
  • Anterior cardinal veins (R and L): internal jugular veins (left brachiocephalic vein is an anastomosis)
  • Anterior cardinal vein (R): part of superior vena cava and right brachiocephalic vein
  • Common cardinal vein (R): proximal part of superior vena cava
  • Common cardinal vein (L): lateral part of coronary sinus and oblique vein of left atrium
  • Posterior cardinal vein (R): part of azygos vein and common iliac veins
  • Supracardinal veins: hemiazygos vein (L) and caudal part of azygos vein (R)
  • Subcardinal vein (R): renal segment of inferior vena cava


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