Atrium (heart) of blood occurs. In birds, mammals, and some other reptiles (alligators in particular) the partitioning of both chambers is complete. Atrium (heart) The atrium is the upper chamber in which blood enters the heart. There are two atria in the human heart – the left atrium connected to the lungs, and the right atrium connected to the venous circulation. The atria receive blood, and when the heart muscle contracts they pump blood to the ventricles. All animals with a closed circulatory system have at least one atrium/auricle (humans have two atria). The atrium used to be called the "auricle", and
Opal (given name) in the 1950s. It was the 344th most common name for females in the United States in the 1990 census. Eighty girls born in the United States in 2010 were given the name and 92 girls born in 2011 were given the name. Opal (given name) Opal is a feminine given name derived from the name of the gemstone opal. The gemstone is the birthstone for October. Its name is derived from the Sanskrit उपल or "upala", which means ""jewel". It came into use along with other gemstone names during the late Victorian era. Opal was among the 100 most