Septum
Encyclopedia
In anatomy
, a septum (Latin for something that encloses; plural septa) is a wall, dividing a cavity or structure into smaller ones.
Histological septa are seen throughout most tissues of the body, particularly where they are needed to stiffen soft cellular tissue, and they also provide planes of ingress for small blood vessels. Because the dense collagen fibres of a septum usually extend out into the softer adjacent tissues, microscopic fibrous septa are less clearly defined than the macroscopic types of septa listed above. In rare instances, a septum is a cross-wall.
Anatomy
Anatomy is a branch of biology and medicine that is the consideration of the structure of living things. It is a general term that includes human anatomy, animal anatomy , and plant anatomy...
, a septum (Latin for something that encloses; plural septa) is a wall, dividing a cavity or structure into smaller ones.
In human anatomy
- Interatrial septumInteratrial septumThe interatrial septum is the wall of tissue that separates the right and left atria of the heart.-Development:The interatrial septum forms during the first and second months of fetal development. Formation of the septum occurs in several stages...
, the wall of tissue that is a sectional part of the left and right atria of the heart - Interventricular septumInterventricular septumInterventricular septum , abbreviated IVS, is the stout wall separating the lower chambers of the heart from one another....
or median septum, the wall separating the left and right ventricles of the heart - Lingual septumLingual septumThe lingual septum consists of a vertical layer of fibrous tissue, extending throughout the entire length of the median plane of the tongue, though not quite reaching the dorsum....
, a vertical layer of fibrous tissue that separates the halves of the tongue - Nasal septumNasal septumThe nasal septum separates the left and right airways in the nose, dividing the two nostrils.It is depressed by the Depressor septi nasi muscle.-Composition:The fleshy external end of the nasal septum is sometimes also called columella....
: the cartilage wall separating the nostrils of the nose
- Alveolar septumAlveolar septumThe alveolar septum separates adjacent alveoli in lung tissue. The minimal components of an alveolar septum consist of the basement membranes of alveolar-lining epithelium and capillary endothelium...
: the thin wall which separates the alveoliPulmonary alveolusAn alveolus is an anatomical structure that has the form of a hollow cavity. Found in the lung parenchyma, the pulmonary alveoli are the dead ends of the respiratory tree, which outcrop from either alveolar sacs or alveolar ducts, which are both sites of gas exchange with the blood as well...
from each other in the lungs - Orbital septumOrbital septumThe orbital septum is a membranous sheet that acts as the anterior boundary of the orbit. It extends from the orbital rims to the eyelids...
, a palpabral ligament in the upper and lower eyelids - Septum pellucidumSeptum pellucidumThe septum pellucidum , and not to be confused with the medial septum, is a thin, triangular, vertical membrane separating the anterior horns of the left and right lateral ventricles of the brain...
or septum lucidum, a thin structure separating two fluid pockets in the brain - Medial septum, a cluster of neuronsNeuronA neuron is an electrically excitable cell that processes and transmits information by electrical and chemical signaling. Chemical signaling occurs via synapses, specialized connections with other cells. Neurons connect to each other to form networks. Neurons are the core components of the nervous...
in close proximity to the septum pellucidumSeptum pellucidumThe septum pellucidum , and not to be confused with the medial septum, is a thin, triangular, vertical membrane separating the anterior horns of the left and right lateral ventricles of the brain... - Uterine septumUterine septumA uterine septum is a form of a congenital malformation where the uterine cavity is partitioned by a longitudinal septum; the outside of the uterus has a normal typical shape...
, a malformation of the uterus - Vaginal septumVaginal septumA vaginal septum is a congenital partition within the vagina; such a septum could be either longitudinal or transverse.-Longitudinal septum – double vagina:...
, a lateral or transverse partition inside the vagina
Histological septa are seen throughout most tissues of the body, particularly where they are needed to stiffen soft cellular tissue, and they also provide planes of ingress for small blood vessels. Because the dense collagen fibres of a septum usually extend out into the softer adjacent tissues, microscopic fibrous septa are less clearly defined than the macroscopic types of septa listed above. In rare instances, a septum is a cross-wall.
In zoology
- One of the radial calcareous plates of a coral. b. One of the transverse partitions dividing the shell of a mollusk, or of a rhizopod, into several chambers. c. One of the transverse partitions dividing the body cavity of an annelid.
- Septum (marine biology): walls between each chamber, or siphuncle, in shells of nautiloids, ammoniteAmmoniteAmmonite, as a zoological or paleontological term, refers to any member of the Ammonoidea an extinct subclass within the Molluscan class Cephalopoda which are more closely related to living coleoids Ammonite, as a zoological or paleontological term, refers to any member of the Ammonoidea an extinct...
s, and belemnitesBelemnoideaBelemnoids are an extinct group of marine cephalopod, very similar in many ways to the modern squid and closely related to the modern cuttlefish. Like them, the belemnoids possessed an ink sac, but, unlike the squid, they possessed ten arms of roughly equal length, and no tentacles...
; i.e. cephalopodCephalopodA cephalopod is any member of the molluscan class Cephalopoda . These exclusively marine animals are characterized by bilateral body symmetry, a prominent head, and a set of arms or tentacles modified from the primitive molluscan foot...
s that retain an external shell.