The sinus venosus is a large quadrangular cavity which precedes the
atrium
Atrium may refer to:
Anatomy
* Atrium (heart), an anatomical structure of the heart
* Atrium, the genital structure next to the genital aperture in the reproductive system of gastropods
* Atrium of the ventricular system of the brain
* Pulmona ...
on the venous side of the
chordate
A chordate () is an animal of the phylum Chordata (). All chordates possess, at some point during their larval or adult stages, five synapomorphies, or primary physical characteristics, that distinguish them from all the other taxa. These fiv ...
heart
The heart is a muscular organ in most animals. This organ pumps blood through the blood vessels of the circulatory system. The pumped blood carries oxygen and nutrients to the body, while carrying metabolic waste such as carbon dioxide t ...
. In mammals, it exists distinctly only in the
embryo
An embryo is an initial stage of development of a multicellular organism. In organisms that reproduce sexually, embryonic development is the part of the life cycle that begins just after fertilization of the female egg cell by the male spe ...
nic heart, where it is found between the two
venae cavae
In anatomy, the venae cavae (; singular: vena cava ; ) are two large veins (great vessels) that return deoxygenated blood from the body into the heart. In humans they are the superior vena cava and the inferior vena cava, and both empty into the ...
. However, the sinus venosus persists in the adult. In the adult, it is incorporated into the wall of the
right atrium
The atrium ( la, ātrium, , entry hall) is one of two upper chambers in the heart that receives blood from the circulatory system. The blood in the atria is pumped into the heart ventricles through the atrioventricular valves.
There are two at ...
to form a smooth part called the sinus venarum, which is separated from the rest of the atrium by a ridge of fibres called the
crista terminalis
The crista terminalis or terminal crest 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 in ...
. The sinus venosus also forms the
sinoatrial node
The sinoatrial node (also known as the sinuatrial node, SA node or sinus node) is an oval shaped region of special cardiac muscle in the upper back wall of the right atrium made up of cells known as pacemaker cells. The sinus node is approxima ...
and the
coronary sinus
In anatomy, the coronary sinus () is a collection of veins joined together to form a large vessel that collects blood from the heart muscle ( myocardium). It delivers deoxygenated blood to the right atrium, as do the superior and inferior ven ...
; in (most) mammals only.
In the embryo, the thin walls of the sinus venosus are connected below with the
right ventricle
A ventricle is one of two large chambers toward the bottom of the heart that collect and expel blood towards the peripheral beds within the body and lungs. The blood pumped by a ventricle is supplied by an atrium, an adjacent chamber in the uppe ...
, and medially with the
left atrium
The atrium ( la, ātrium, , entry hall) is one of two upper chambers in the heart that receives blood from the circulatory system. The blood in the atria is pumped into the heart ventricles through the atrioventricular valves.
There are two atr ...
, but are free in the rest of their extent. It receives blood from the
vitelline vein
The vitelline veins are veins that drain blood from the yolk sac and the gut tube during gestation.
Path
They run upward at first in front, and subsequently on either side of the intestinal canal. They unite on the ventral aspect of the canal.
...
,
umbilical vein
The umbilical vein is a vein present during fetal development that carries oxygenated blood from the placenta into the growing fetus. The umbilical vein provides convenient access to the central circulation of a neonate for restoration of blood v ...
and
common cardinal vein.
The sinus venosus 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
In anatomy, the coronary sinus () is a collection of veins joined together to form a large vessel that collects blood from the heart muscle ( myocardium). It delivers deoxygenated blood to the right atrium, as do the superior and inferior ven ...
(right atrium) and
oblique vein of the
left atrium
The atrium ( la, ātrium, , entry hall) is one of two upper chambers in the heart that receives blood from the circulatory system. The blood in the atria is pumped into the heart ventricles through the atrioventricular valves.
There are two atr ...
, whereas the right part becomes incorporated into the
right atrium
The atrium ( la, ātrium, , entry hall) is one of two upper chambers in the heart that receives blood from the circulatory system. The blood in the atria is pumped into the heart ventricles through the atrioventricular valves.
There are two at ...
to form the sinus venarum.
Additional images
File:Gray461.png, Diagram to illustrate the simple tubular condition of the heart.
File:Gray462.png, Heart of human embryo of about fourteen days.
File:Gray477.svg, Scheme of arrangement of parietal veins.
See also
*
Atrial septal defect
Atrial septal defect (ASD) is a congenital heart defect in which blood flows between the atria (upper chambers) of the heart. Some flow is a normal condition both pre-birth and immediately post-birth via the foramen ovale; however, when this d ...
*
Bulbus cordis
The bulbus cordis (the bulb of the heart) is a part of the heart development, developing heart that lies ventral to the primitive ventricle after the heart assumes its S-shaped form. The superior end of the bulbus cordis is also called the conotrun ...
*
Ducts of Cuvier
*
Primitive ventricle
The primitive ventricle or embryonic ventricle of the developing heart, together with the bulbus cordis that lies in front of it, gives rise to the left and right ventricles. The primitive ventricle provides the trabeculated parts of the walls, a ...
*
Primitive atrium
The primitive atrium is 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 ...
*
Ductus venosus
In the fetus, the ''ductus venosus'' (Arantius' duct after Julius Caesar Aranzi) shunts a portion of umbilical vein blood flow directly to the inferior vena cava. Thus, it allows oxygenated blood from the placenta to bypass the liver. Compared to ...
*
Truncus arteriosus
The truncus arteriosus is a structure that is present during embryonic development. It is an arterial trunk that originates from both ventricles of the heart that later divides into the aorta and the pulmonary trunk.
Structure
The truncus arterio ...
*
Sinus venosus atrial septal defect
A sinus venosus atrial septal defect is a type of atrial septal defect primarily associated with the sinus venosus.
They represent 5% of atrial septal defects.Robbins and Cotran Pathologic Basis of Disease 8th Edition
They can occur near the supe ...
References
External links
* - Gross anatomy of the adult heart
* - "Right atrium, internal structure, anterior view"
{{Authority control
Embryology of cardiovascular system
de:Sinus venosus
zh:静脉窦