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
Douglas (given name) Douglas (given name) Douglas is a Scottish masculine given name which originated from the surname "Douglas". Although today the name is almost exclusively given to boys, it was used as girls name in the seventeenth and eighteenth centuries, in the north of England. The Scottish surname "Douglas" was borne by one of the most powerful families of the Kingdom of Scotland (the Earls of Douglas, Angus, Morton, Dukes of Hamilton and others). It has sometimes been stated that the given name is connected with the given name "Dougal", although it is more likely derived from the surname already mentioned. Linguistically,