Terminal bar is a
histological
Histology,
also known as microscopic anatomy or microanatomy, is the branch of biology that studies the microscopic anatomy of biological tissue (biology), tissues. Histology is the microscopic counterpart to gross anatomy, which looks at large ...
term given to the
unresolved group of
junctional complexes that attach adjacent
epithelial cells
Epithelium or epithelial tissue is a thin, continuous, protective layer of cells with little extracellular matrix. An example is the epidermis, the outermost layer of the skin. Epithelial ( mesothelial) tissues line the outer surfaces of man ...
on their lateral surfaces: the
zonula occludens,
zonula adherens
In cell biology, adherens junctions (or zonula adherens, intermediate junction, or "belt desmosome") are protein complexes that occur at cell–cell junctions and cell–matrix junctions in epithelial and endothelial tissues, usually more basal ...
,
macula adherens and
macula communicans.
Using
light microscopy
Microscopy is the technical field of using microscopes to view subjects too small to be seen with the naked eye (objects that are not within the resolution range of the normal eye). There are three well-known branches of microscopy: optical, el ...
, the terminal bar appears as a bar or spot at the
apical surface
The cell membrane (also known as the plasma membrane or cytoplasmic membrane, and historically referred to as the plasmalemma) is a biological membrane that separates and protects the interior of a cell from the outside environment (the extra ...
of the
cell
Cell most often refers to:
* Cell (biology), the functional basic unit of life
* Cellphone, a phone connected to a cellular network
* Clandestine cell, a penetration-resistant form of a secret or outlawed organization
* Electrochemical cell, a de ...
, wherein the structures listed cannot be resolved. With
electron microscopy
An electron microscope is a microscope that uses a beam of electrons as a source of illumination. It uses electron optics that are analogous to the glass lenses of an optical light microscope to control the electron beam, for instance focusing i ...
, it can be visually disseminated into these structures.
The terminal bar is located on the lateral surface of epithelial cells, where the lateral surface meets the apical surface. It should not be confused with the
terminal web
The terminal web is a structure found at the apical surface of epithelial cells that possess microvilli. It is composed primarily of actin filaments stabilized by spectrin, which also anchors the terminal web to the apical cell membrane. The pr ...
, which is an
actinous web underlying
microvilli
Microvilli (: microvillus) are microscopic cellular membrane protrusions that increase the surface area for diffusion and minimize any increase in volume, and are involved in a wide variety of functions, including absorption, secretion, cellula ...
on specialized epithelial cells.
References
Cell anatomy
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