Atrium (heart) similar function. Some animals (amphibians and reptiles) have a three-chambered heart, in which the blood from each atrium is mixed in the single ventricle before being pumped to the aorta. In these animals, the left atrium still serves the purpose of collecting blood from the pulmonary veins. In some fish, the circulatory system is very simple: a two-chambered heart including one atrium and one ventricle. Among sharks, the heart consists of four chambers arranged serially (and therefore called a serial heart): blood flows into the most posterior chamber, the sinus venosus, and then to the atrium which moves it to
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