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
Sandra (given name) Sandra (given name) Sandra is a female name, which is often used as a short form for Alexandra or Cassandra. Alexandra is a feminine form of the male name Alexander, which is a romanization of the Greek name Ἀλέξανδρος "Alexandros". It is generally interpreted to mean "protector of man" or "defender of man". The name Cassandra is also from the Greek (: "she who entangles men"). Cassandra is known in Greek mythology, as the daughter of King Priam and Queen Hecuba of Troy. She was loved by Apollo and given the gift of prophecy but when she did not fall