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
Spencer (given name) Spencer (given name) Spencer is a given name of British origin, meaning "steward" or "administrator". It is a shortened form of the English word "dispenser", which derives from Anglo-French "dispensour", from Old French "dispenseor", from Latin "dispensatorem", the agent noun of "dispensare", meaning "to disperse, administer, and distribute (by weight)". The name originated as the surname Spencer, but later gradually came to be used as a given name as well. From its origin as a surname, it has been given to both males and females, but it has historically been more common as a name for males. According to the