septa

Septa (singular septum) are walls or partitions that divide a cavity, organ, or structure into smaller compartments. The term derives from Latin septum, meaning a fence or enclosure, and the plural septa is commonly used across different fields.

In human anatomy, septa partition several structures. The nasal septum divides the nasal cavity into two nostrils. The heart contains interatrial and interventricular septa that separate the atria and ventricles, respectively. The brain features several septa, such as the septum pellucidum, a thin membrane between parts of the lateral ventricles. Embryology also involves various septa that partition developing organs.

In fungi and plants, septa refer to cross walls within multicellular filaments or reproductive structures. In fungi, hyphae can be septate, with pores that allow transfer of cytoplasm and organelles between cells. In plants, septa can occur within sporangia or other enclosing structures, dividing them into compartments.

In zoology and paleontology, many shells, including those of nautiloids and ammonites, are chambered by septa. The animal typically resides in the outermost chamber, while successive septa create internal compartments that can influence buoyancy or growth; some species regulate gas between chambers via a siphuncle that traverses the septa.

Clinically, septa are significant when they form defects. Atrial septal defects and ventricular septal defects are congenital openings that disrupt normal blood flow. Septoplasty is a surgical procedure to correct a deviated nasal septum, improving breathing.