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
Aonghas (given name) According to historian Alex Woolf, the early Gaelic form of the name, "Oengus", was borrowed from the Pictish "Onuist", which appears in British as "Ungust". Woolf noted that these names are all derived from the Celtic "*Oinogustos". Linguist John Kneen derived this name from two Celtic elements the following way: "*Oino-gustos", meaning "one-choice". Woolf also stated that between about AD 350 and AD 660, the Insular Celtic dialects underwent changes which included the loss of the final syllables and unstressed vowels, which affected "*Oinogustos" thus: "*Oin<del>o</del>gust<del>os</del>". Aonghas (given name) Aonghas is a masculine given name in Scottish Gaelic. It is