Kaksikammioisia

Kaksikammioisia is a Finnish adjective meaning two-chambered. The form kaksikammioisia is the partitive plural used when describing plural nouns, for example kaksikammioisia sydämiä, “two-chambered hearts.” The term is commonly used in biology, anatomy and physiology to categorize structures or organisms that consist of two chambers.

In vertebrate anatomy, a two-chambered heart typically consists of an atrium and a ventricle and supports a single circulatory loop. This arrangement is characteristic of many fish species and some extinct vertebrates. Blood moves from the atrium to the ventricle and is then pumped to the gills for oxygenation before circulating to the rest of the body. Because the circuit involves mixing of oxygenated and deoxygenated blood in a single ventricle, the system is generally less oxygen-efficient than three- or four-chambered hearts.

Beyond hearts, the descriptor can apply to other two-chambered compartments in biological structures, though its most common usage is in reference to cardiac anatomy. The term contrasts with three- and four-chambered configurations found in amphibians, reptiles, birds, and mammals, which provide greater separation of oxygen-rich and oxygen-poor blood and higher metabolic efficiency.

See also: heart, comparative anatomy, circulatory system.