septum

views updated May 08 2018

septum (pl. septa) A cross wall or partition.
1. A morphological term used particularly with reference to the Cephalopoda, whose shells are divided internally into a series of chambers (camerae) by septa which are generally concave towards the anterior. There is an opening (foramen) in each septum and this is usually bordered by a collar (septal neck). Septal necks are forward-pointing (prochoanitic) in ammonoids (Ammonoidea) and backward-pointing (retro-choanitic) in nautiloids (Nautiloidea). In many ammonoids the septum becomes fluted and there has been much discussion concerning the function of the complex fluting.

2. The radially arranged plates that occur in the corallum of corals. The first-formed septa are called ‘prosepta’ and are usually larger than the metasepta, which occur between them.

septum

views updated Jun 11 2018

sep·tum / ˈseptəm/ • n. (pl. -ta / -tə/ ) chiefly Anat. Biol. a partition separating two chambers, such as that between the nostrils or the chambers of the heart.

septum

views updated Jun 11 2018

septum
1. (pl. septa) A cross-wall or partition. In Cephalopoda, the shell consists of individual compartments (camerae) separated by septa. In Annelida, the septa internally divide the individual segments of the body.

2. See SEPTATE JUNCTION.

septum

views updated May 23 2018

septum (anat., bot., zool.) dividing wall or partition. XVIII. — L. sēptum, sæptum, f. sēpīre, sæpīre enclose, f. sēpes, sæpes hedge.

septum

views updated Jun 08 2018

septum (sep-tŭm) n. (pl. septa) a partition or dividing wall within an anatomical structure.
septal adj. —septate (sep-tayt) adj.

septum

views updated May 18 2018

septum (pl. septa) Any dividing wall in a plant or animal. Examples are the septa that separate the chambers of the heart.

septum

views updated May 21 2018

septum (pl. septa) A cross-wall or partition.