2/14/2022
EMBRYOLOGY
OF
CARDIOVASCULAR SYSTEM (1)
(Formation of Heart Tube &
Loop)
PREPARED BY PROF GT LEBONA
PRESENTED BY MR NK XHAKAZA
EMBRYOLOGY OF CVS
EXTRAEMBRYONIC CIRCULATION
In 1st 3 weeks
• Embryo receives O2/nutrients in
exchange for CO2/metabolites by
diffusion.
• System for exchange with maternal
circulation established after.
2
1
, 2/14/2022
EMBRYOLOGY OF CVS
EXTRAEMBRYONIC CIRCULATION
Angiogenetic cells (angioblasts)
appear in:
• Wall of yolk sac.
• Connecting stalk (future site of
umbilicus).
• Chorion (placental site where 2
layers of trophoblast are embedded
in endometrium).
3
EMBRYOLOGY OF CVS
EXTRAEMBRYONIC CIRCULATION
• Angioblasts aggregate into clusters
of blood islands.
• Small cavities appear within blood
islands.
• Peripheral cells flatten to form single
layer of endothelium.
• Centrally-placed cells coalesce to
form red blood cells.
• Endothelial-lined cavities fuse to form 1
vessels.
• > 1st indication of vascular
circulation.
3
2
4
2
EMBRYOLOGY
OF
CARDIOVASCULAR SYSTEM (1)
(Formation of Heart Tube &
Loop)
PREPARED BY PROF GT LEBONA
PRESENTED BY MR NK XHAKAZA
EMBRYOLOGY OF CVS
EXTRAEMBRYONIC CIRCULATION
In 1st 3 weeks
• Embryo receives O2/nutrients in
exchange for CO2/metabolites by
diffusion.
• System for exchange with maternal
circulation established after.
2
1
, 2/14/2022
EMBRYOLOGY OF CVS
EXTRAEMBRYONIC CIRCULATION
Angiogenetic cells (angioblasts)
appear in:
• Wall of yolk sac.
• Connecting stalk (future site of
umbilicus).
• Chorion (placental site where 2
layers of trophoblast are embedded
in endometrium).
3
EMBRYOLOGY OF CVS
EXTRAEMBRYONIC CIRCULATION
• Angioblasts aggregate into clusters
of blood islands.
• Small cavities appear within blood
islands.
• Peripheral cells flatten to form single
layer of endothelium.
• Centrally-placed cells coalesce to
form red blood cells.
• Endothelial-lined cavities fuse to form 1
vessels.
• > 1st indication of vascular
circulation.
3
2
4
2
