Introduction
without definitions
with definitionsThe blood flows into the heart from the paired umbilical and omphalomesenteric veins. It leaves the heart via the pair of aortic arches in order to get into the embryo's blood circulation system.
With ca. the 28th day (stage 10) the heart of the embryo begins to beat. Initially this only causes a back and forth movement of the blood to occur, but very soon a directional flow of the blood begins from the inflow tract over the atrium and ventricle part in the conus cordis and the pair of aortic arches. The inflow tract contains oxygen-rich blood from the umbilical veins and a contribution from the omphalomesenteric veins.
(ca. the 28th day)
- Endocardial loop
- First aortic arch
- Foregut
- Cardiac jelly in the myocardiac mantle
- Pericardial cavity
- Amniotic cavity
- Midgut
- Septum transversum
- Umbilical vein
- Omphalomesenteric veine
(ca. the 28th day)
- Endocardial loop
- First aortic arch
- Foregut
- Cardiac jelly in the myocardiac mantle
- Pericardial cavity
- Amniotic cavity
- Midgut
- Septum transversum
- Umbilical vein
- Omphalomesenteric veine
In the embryo, the first heart contractions can be detected in stage 8 (ca. the 23rd day). In the beginning, the frequency is limited to roughly 70 contractions per minute. Up to the 7th week of pregnancy, though, the frequency increases to 170 - 190 beats /minute and at birth the heart beats at 160 - 180 times per minute.