Atrium (heart) 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 that term is still used to describe this chamber in, for example, the "Mollusca", but in humans that name is
Riley (given name) Riley (given name) Riley is a unisex given name, which first appeared as "Raghallach", which was originated on a man who died in the Battle of Clontarf. Its source gives its meaning as "valiant". Riley in the United States is mostly a girl's name. In 2017, it was the twenty-fifth most popular girl's name, and the 253rd most popular boy's name. The opposite is true for the UK, where it is primarily a boy's name, being the fortieth most popular name given to baby boys in 2016. Riley is also a popular surname. The surname's first variant is Ó Raghallaigh