Bifhárum

Bifhárum is the Icelandic term that corresponds to the English word cilia. In biology, bifhár are hair-like organelles that protrude from the surface of many eukaryotic cells. They are typically short and numerous, in contrast with flagella, which are longer and fewer in number. Cilia can be motile, beating in coordinated patterns to move fluid, mucus, or the cell itself, or non-motile (primary cilia), which mostly serve sensory and signaling roles.

At the cellular level, a motile cilium contains an axoneme with microtubules arranged in a 9+2 pattern and is anchored by a basal body derived from a centriole. The dynein motor proteins drive the bending movements of the axoneme, enabling propulsion or fluid movement across the cell surface.

Distribution and function: Cilia are found on many animal cells, including those lining the respiratory tract and oviduct, as well as on many protists and some algae. In plants, cilia are limited to certain reproductive cells in some lineages. The beating of motile cilia clears mucus and debris in airways and helps move eggs through the oviduct, while primary cilia act as sensory antennas that detect mechanical and chemical signals and participate in signaling pathways during development.

Etymology and usage: In Icelandic scientific literature, bifhár refers to cilia, with bifhárum being the inflected form used in sentences.