Embryo

• What is the first organ to function in human embryo

  The heart
• When does the heart start beating?

  Day 21
• When does the circulatory system start pumping blood?

  Day 24-25
• Remodelling and septation occur when the heart is still pumping what?

  Nutrients, oxygen, disposable waste, electrical activity
• What shape does the heart initially take?

  A tube
• What day does the heart bend into a C shape?

  Day 23
• What day does the heart bend into an S shape?

  Day 24
• What day does the heart form a U shape?

  Day 28
• What is derived from the interembryonic mesoderm (from the primitive streak)?

  Cardiac Progenitor
• What do blood islands form?

  They form right and left endocardial tubes
• What does the first heart field become?

  Right and left atria, left ventricle, and a portion of right ventricle
• What does the second heart field form?

  Right ventricle outflow tract
• What are the three components of the endocardial tube?

  Epicardium, myocardium, endocardium
• What is the epicardium composed of?

  Visceral lining of pericardial cavity covering the heart
• What is the myocardium composed of?

  Splanchnic mesoderm
• What is the endocardium composed of?

  Cardiac jelly
• What are the parts of the primary tube (caudal to cranial)?


  Sinus venous, primitive atrium, primitive ventricle, bulbous cordi, teuncus arterious, aortic sac.
• During the S curve of day 24, what changes have been made?

  Ventricle moves to the left, atrium pushed dorsally and cranially
• What orientation does the heart tube loop?

  Right to left, cranial caudal axis
• Formation of the primitive blood vessel:


  1) inflow to hearts supplies 6 vessels

  2) venous blood enters the short trunk, vitelline (drain the yolk sac), and umbilical vein
• When does venous system remodelling start?

  Day 22
• What do the cardinal veins do on day 22

  Drain the 2 sides of the body
• What does the entire venous system enter through?

  The right sinus horn
• What enlarges to keep up with the rapid growth of the heart?

  Right sinus horn and caval vein
• What do the right sinus horn and caval vein do aside from rapid growth?

  Attaches to the right atrium
• Cardinal veins:


  Superior vena cava, jugular vein, left brachio cephalic
• What does the umbilical cord connect to?

  Ligamentum teres hepatis
• What does the vitelline vein connect to?

  Right inferior vena cava
• What way does the pulmonary vein shift to?

  The left
• How many pulmonary veins grow into the lungs

  Two into each lung
• What do the pulmonary veins in the lungs grow into?

  Bronchial buds
• What is the endocardial cushion?


  Small bulges that grow and meet in the middle of the heart
• What do the endocardial cushions do?

  separate the sides of the heart and septate the atria, divide the atrioventricular canal
• What day does the atrioventricular canal divide?

  Day 30
• What grows down and creates part of the hole between the atria?

  Septum primum
• What is the hole in the septum primum called?

  Osteum Primum
• What forms in the septum primum via apoptosis?

  Ostium secundum
• What is the one way shunt between the atriums?

  Foramen ovale
• Once the AV canal, ventricles, and cardiac outflow tracts are all aligned, what can happen?

  The last stages of heart morphogenesis