Heart depending on what is counted as a chamber. The atrium and ventricle are sometimes considered "true chambers", while the others are considered "accessory chambers". Primitive fish have a four-chambered heart, but the chambers are arranged sequentially so that this primitive heart is quite unlike the four-chambered hearts of mammals and birds. The first chamber is the sinus venosus, which collects deoxygenated blood from the body through the hepatic and cardinal veins. From here, blood flows into the atrium and then to the powerful muscular ventricle where the main pumping action will take place. The fourth and final chamber is the
Riley (given name) (Descendent of/Of Raghallach) which was later adapted in English as O'Reilly which itself has been anglicised into "Reilly". The surname "Riley" is a translated version of Reilly; which evolved over time. It currently is #8 in England and Wales, #9 in Northern Ireland, #15 in Scotland, #30 in Australia and New Zealand, #64 in Canada, #156 in the United States, and #198 in the Netherlands. 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