Sinus venosus
Encyclopedia
The sinus venosus is a large quadrangular cavity which precedes the atrium on the venous side of the chordate
heart
. In humans, it exists distinctly only in the embryo
nic heart, where it is found between the two venae cavae
. In the adult, it is incorporated into the wall of the right atrium
to form a smooth part called the sinus venarum, also known as the venarum sinus, which is separated from the rest of the atrium by a ridge of fibres called the crista terminalis
. The sinus venosus also forms the SA node and the coronary sinus
.
In the embryo, the thin walls of the sinus venosus are connected below with the right ventricle
, and medially with the left atrium
, but are free in the rest of their extent. It receives blood from the vitelline vein, umbilical vein
and common cardinal vein.
It originally starts as a paired structure but shifts towards associating only with the right atrium as the embryonic heart develops. The left portion shrinks in size and eventually forms the coronary sinus
and oblique vein of the left atrium
, whereas the right part becomes incorporated into the right atrium
to form the sinus venarum.
Chordate
Chordates are animals which are either vertebrates or one of several closely related invertebrates. They are united by having, for at least some period of their life cycle, a notochord, a hollow dorsal nerve cord, pharyngeal slits, an endostyle, and a post-anal tail...
heart
Heart
The heart is a myogenic muscular organ found in all animals with a circulatory system , that is responsible for pumping blood throughout the blood vessels by repeated, rhythmic contractions...
. In humans, it exists distinctly only in the embryo
Embryo
An embryo is a multicellular diploid eukaryote in its earliest stage of development, from the time of first cell division until birth, hatching, or germination...
nic heart, where it is found between the two venae cavae
Venae cavae
The superior and inferior vena cava are collectively called the venae cavae. They are the veins that return deoxygenated blood from the body into the heart. They both empty into the right atrium....
. In the adult, it is incorporated into the wall of the right atrium
Right atrium
The right atrium is one of four chambers in the hearts of mammals and archosaurs...
to form a smooth part called the sinus venarum, also known as the venarum sinus, which is separated from the rest of the atrium by a ridge of fibres called the crista terminalis
Crista terminalis
The Crista Terminalis represents the junction between the sinus venosus and the heart in the developing embryo. In the development of the human heart, the right horn and transverse portion of the sinus venosus ultimately become incorporated with and form a part of the adult right atrium...
. The sinus venosus also forms the SA node and the coronary sinus
Coronary sinus
The coronary sinus is a collection of veins joined together to form a large vessel that collects blood from the myocardium of the heart. It is present in all mammals, including humans...
.
In the embryo, the thin walls of the sinus venosus are connected below with the right ventricle
Right ventricle
The right ventricle is one of four chambers in the human heart. It receives deoxygenated blood from the right atrium via the tricuspid valve, and pumps it into the pulmonary artery via the pulmonary valve and pulmonary trunk....
, and medially with the left atrium
Left atrium
The left atrium is one of the four chambers in the human heart. It receives oxygenated blood from the pulmonary veins, and pumps it into the left ventricle, via the mitral valve.-Foramen ovale:...
, but are free in the rest of their extent. It receives blood from the vitelline vein, umbilical vein
Umbilical vein
The umbilical vein is a vein present during fetal development that carries oxygenated blood from the placenta to the growing fetus.The blood pressure inside the umbilical vein is approximately 20 mmHg.-Development:...
and common cardinal vein.
It originally starts as a paired structure but shifts towards associating only with the right atrium as the embryonic heart develops. The left portion shrinks in size and eventually forms the coronary sinus
Coronary sinus
The coronary sinus is a collection of veins joined together to form a large vessel that collects blood from the myocardium of the heart. It is present in all mammals, including humans...
and oblique vein of the left atrium
Left atrium
The left atrium is one of the four chambers in the human heart. It receives oxygenated blood from the pulmonary veins, and pumps it into the left ventricle, via the mitral valve.-Foramen ovale:...
, whereas the right part becomes incorporated into the right atrium
Right atrium
The right atrium is one of four chambers in the hearts of mammals and archosaurs...
to form the sinus venarum.
See also
- Atrial septal defect
- Bulbus cordisBulbus cordisThe bulbus cordis lies ventral to the primitive ventricle after the developing heart assumes its S-shaped form...
- Ducts of CuvierDucts of CuvierDuring development of the veins, the first indication of a parietal system consists in the appearance of two short transverse veins, the ducts of Cuvier , which open, one on either side, into the sinus venosus. Each of these ducts receives an ascending and descending vein...
- Primitive ventriclePrimitive ventricleThe embryonic ventricle or primitive ventricle of the developing heart gives rise to the trabeculated parts of the left and right ventricles...
- Primitive atriumPrimitive atriumThe primitive atrium is a term used to describe a stage in the embryonic development of the human heart. It grows rapidly and partially encircles the bulbus cordis; the groove against which the bulbus cordis lies is the first indication of a division into right and left atria.The cavity of the...
- Ductus venosusDuctus venosusIn the fetus, the ductus venosus shunts approximately half of the blood flow of the umbilical vein directly to the inferior vena cava. Thus, it allows oxygenated blood from the placenta to bypass the liver. In conjunction with the other fetal shunts, the foramen ovale and ductus arteriosus, it...
- Truncus ArteriosusTruncus arteriosus (embryology)The truncus arteriosus and bulbus cordis are divided by the aorticopulmonary septum. The truncus arteriosus gives rise to the ascending aorta and the pulmonary trunk. The caudal end of the bulbus cordis gives rise to the smooth parts of the left and right ventricles...
- Sinus venosus atrial septal defectSinus venosus atrial septal defectA Sinus venosus atrial septal defect is a type of atrial septal defect primarily associated with the sinus venosus.They represent 10% of atrial septal defects.They can occur near the superior vena cava or inferior vena cava, but the former are more common....