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
Isla (given name) Isla (given name) Isla ( ) is a feminine given name traditionally of primarily Scottish usage, derived from "Islay", which is the name of an island off the west coast of Scotland. It is also the name of two Scottish rivers. In 2016, it was both the fourth most popular name for baby girls born in Scotland and the fourth most popular name for girls born in England and Wales. It was among the top 10 names given to girls born on the Isle of Man in 2009 and one of the top five names for girls born in Guernsey