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Sinus Venosus
The sinus venosus is a large quadrangular cavity which precedes the atrium on the venous side of the chordate heart. In mammals, the sinus venosus exists distinctly only in the embryonic heart where it is found between the two venae cavae; in the adult, the sinus venosus becomes incorporated into the wall of the right atrium to form a smooth part called the sinus venarum which is separated from the rest of the atrium by a ridge called the crista terminalis. In most mammals, the sinus venosus also forms the sinoatrial node and the coronary sinus. Development 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 The common cardinal veins, also known as the ducts of Cuvier, [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Anatomical Terms Of Location
Standard anatomical terms of location are used to describe unambiguously the anatomy of humans and other animals. The terms, typically derived from Latin or Greek roots, describe something in its standard anatomical position. This position provides a definition of what is at the front ("anterior"), behind ("posterior") and so on. As part of defining and describing terms, the body is described through the use of anatomical planes and axes. The meaning of terms that are used can change depending on whether a vertebrate is a biped or a quadruped, due to the difference in the neuraxis, or if an invertebrate is a non-bilaterian. A non-bilaterian has no anterior or posterior surface for example but can still have a descriptor used such as proximal or distal in relation to a body part that is nearest to, or furthest from its middle. International organisations have determined vocabularies that are often used as standards for subdisciplines of anatomy. For example, '' Termi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 volume and for administration of glucose and drugs. The blood pressure inside the umbilical vein is approximately 20 mmHg.Wang, Y. Vascular biology of the placenta. in Colloquium Series on Integrated Systems Physiology: from Molecule to Function. 2010. Morgan & Claypool Life Sciences. Fetal circulation The unpaired umbilical vein carries oxygen and nutrient rich blood derived from fetal-maternal blood exchange at the chorionic villi. More than two-thirds of fetal hepatic circulation is via the main portal vein, while the remainder is shunted from the left portal vein via the ductus venosus to the inferior vena cava, eventually being delivered to the fetal right atrium. Closure Closure of the umbilical vein usually occurs after the umbilic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Embryology Of Cardiovascular System
Embryology (from Greek ἔμβρυον, ''embryon'', "the unborn, embryo"; and -λογία, ''-logia'') is the branch of animal biology that studies the prenatal development of gametes (sex cells), fertilization, and development of embryos and fetuses. Additionally, embryology encompasses the study of congenital disorders that occur before birth, known as teratology. Early embryology was proposed by Marcello Malpighi, and known as preformationism, the theory that organisms develop from pre-existing miniature versions of themselves. Aristotle proposed the theory that is now accepted, epigenesis. Epigenesis is the idea that organisms develop from seed or egg in a sequence of steps. Modern embryology developed from the work of Karl Ernst von Baer, though accurate observations had been made in Italy by anatomists such as Aldrovandi and Leonardo da Vinci in the Renaissance. Comparative embryology Preformationism and epigenesis As recently as the 18th century, the prevailing ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 superior vena cava or inferior vena cava The inferior vena cava is a large vein that carries the deoxygenated blood from the lower and middle body into the right atrium of the heart. It is formed by the joining of the right and the left common iliac veins, usually at the level of the ..., but the former are more common. They can be associated with anomalous pulmonary venous connection. References External links Congenital heart defects {{Circulatory-stub} ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Truncus Arteriosus (embryology)
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 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 (outflow tract) of the left and right ventricles (aortic vestibule & conus arteriosus respectively). The cranial end of the bulbus cordis (also known as the conus cordis) gives rise to the aorta and pulmonary trunk with the truncus arteriosus. This makes its appearance in three portions. # Two distal ridge-like thickenings project into the lumen of the tube: the truncal and bulbar ridges. These increase in size, and ultimately meet and fuse to form a septum ( aorticopulmonary septum), which takes a spiral course toward the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ductus Venosus
In the fetus, the ''ductus venosus'' (''"DV"''; 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 the 50% shunting of umbilical blood through the ''ductus venosus'' found in animal experiments, the degree of shunting in the human fetus under physiological conditions is considerably less, 30% at 20 weeks, which decreases to 18% at 32 weeks, suggesting a higher priority of the fetal liver than previously realized. In conjunction with the other fetal shunts, the ''foramen ovale'' and ''ductus arteriosus'', it plays a critical role in preferentially shunting oxygenated blood to the fetal brain. It is a part of fetal circulation. Anatomic course The pathway of fetal umbilical venous flow is umbilical vein \rightarrow left portal vein \rightarrow ''ductus venosus'' \rightarrow ''inferior vena cava'' \rightarrow eventually r ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 atria. The cavity of the primitive atrium becomes subdivided into right and left chambers by a septum, the septum primum, which grows downward into the cavity. For a time the atria communicate with each other by an opening, the primary interatrial foramen, below the free margin of the septum. This opening is closed by the union of the septum primum with the septum intermedium, and the communication between the atria is re-established through an opening which is developed in the upper part of the septum primum; this opening is known as the foramen ovale (ostium secundum of Born) and persists until birth. A second septum, the septum secundum, semilunar in shape, grows downward from the upper wall of the atrium immediately to the righ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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, and the bulbus cordis the smooth parts. The primitive ventricle becomes divided by the septum inferius which develops into the interventricular septum. The septum grows upward from the lower part of the ventricle, at a position marked on the heart's surface by a furrow. Its dorsal part increases more rapidly than its ventral portion, and fuses with the dorsal part of the septum intermedium Endocardial cushions project into the atrial canal, and, meeting in the middle line, unite to form the septum intermedium which divides the canal into two channels, the future right and left atrioventricular orifices. References External links .... For a time an interventricular foramen exists above its ventral portion, but this foramen is ultim ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ducts Of Cuvier
The common cardinal veins, also known as the ducts of Cuvier, are veins that drain into the during . These drain an and a |
Bulbus Cordis
The bulbus cordis (the bulb of the heart) is a part of the 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 conotruncus. Structure In the early tubular heart, the bulbus cordis is the major outflow pathway. It receives blood from the primitive ventricle, and passes it to the truncus arteriosus. After heart looping, it is located slightly to the left of the ventricle. Development The early bulbus cordis is formed by the fifth week of development. The truncus arteriosus is derived from it later. The adjacent walls of the bulbus cordis and ventricle approximate, fuse, and finally disappear, and the bulbus cordis now communicates freely with the right ventricle, while the junction of the bulbus with the truncus arteriosus is brought directly ventral to and applied to the atrial canal. By the upgrowth of the ventricular septum the bulbus cordis is separated from ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Atrial Septal Defect
Atrial septal defect (ASD) is a congenital heart defect in which blood flows between the atrium (heart), atria (upper chambers) of the heart. Some flow is a normal condition both pre-birth and immediately post-birth via the Foramen ovale (heart), foramen ovale; however, when this does not naturally close after birth it is referred to as a patent (open) foramen ovale (PFO). It is common in patients with a congenital interatrial septum, atrial septal aneurysm (ASA). After PFO closure the atria normally are separated by a dividing wall, the interatrial septum. If this septum is defective or absent, then oxygen-rich blood can flow directly from the left side of the heart to mix with the oxygen-poor blood in the right side of the heart; or the opposite, depending on whether the left or right atrium has the higher blood pressure. In the absence of other heart defects, the left atrium has the higher pressure. This can lead to lower-than-normal oxygen levels in the arterial blood that su ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oblique Vein
The oblique vein of the left atrium (oblique vein of Marshall) is a small vein which descends obliquely on the back of the left atrium and ends in the coronary sinus near its left extremity; it is continuous above with the ligament of the left vena cava (vestigial fold of Marshall), and the two structures form the remnant of the left Cuvierian duct. This obscure region of cardiac perfusion adjacent to the SA node rocks back and forth under systole and diastole Diastole ( ) is the relaxed phase of the cardiac cycle when the chambers of the heart are refilling with blood. The contrasting phase is systole when the heart chambers are contracting. Atrial diastole is the relaxing of the atria, and ventricul ... thus further influencing cardiac autonomic innervation. Ablation of this channel seems reasonable to many observers. Additional images File:Gray480.png, Diagram showing completion of development of the parietal veins. References Thoracic veins Veins of the torso ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
