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) of the given name is , which is pronounced ; a variant form of this name is "Dougalasa". The given name "Doug" is a common short form variant of "Douglas". Pet forms of the given name include: "Dougie" and "Duggie". In Scotland, while spelled "Dougie" like the above, there is a distinct Scottish pronunciation of "Doogie". 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