Basal lamina

Basal lamina

The basal lamina is a layer of extracellular matrix on which epithelium sits and which is secreted by the epithelial cells. It is often confused with the basement membrane, and sometimes used inconsistently in the literature, see below.

It is typically about 40-50 nanometres thick (with exceptions such as the basal laminae that compose the 100-200 nanometre thick glomerular basement membrane).


The layers of the basal lamina ("BL") and those of the basement membrane ("BM") are described below:

Anchoring fibrils composed of type VII collagen extend from the basal lamina into the underlying reticular lamina and loop around collagen bundles. Although found beneath all basal laminae, they are especially numerous in stratified squamous cells of the skin.

These layers should not be confused with the lamina propria, which is found outside the basal lamina. [BUHistology|22203loa]

Basal lamina vs. basement membrane

The term "basal lamina" is usually used with electron microscopy, while the term "basement membrane" is usually used with light microscopy. The structure known as the basement membrane in light microscopy refers to the stained structure anchoring an epithelial layer. This encompasses the basal lamina secreted by epithelial cells and typically a reticular lamina secreted by other cells.

The basal lamina "cannot" be distinguished under the light microscope, but under the higher magnification of an electron microscope, the basal lamina and lamina reticularis are visibly distinct structures.

Some theorize that the lamina lucida is an artifact created when preparing the tissue, and that the basement membrane is therefore equal to the lamina densa in vivo. [cite journal | author = Chan F, Inoue S | title = Lamina lucida of basement membrane: an artefact | journal = Microsc Res Tech | volume = 28 | issue = 1 | pages = 48–59 | year = 1994 | pmid = 8061357 | doi = 10.1002/jemt.1070280106]

Examples of basement membranes include:
* Basilar membrane
* Bruch's membrane
* Descemet's membrane
* Glomerular basement membrane

ee also

* Alveolar-capillary barrier
* Basolateral membrane
* Collagen
* Glomerular basement membrane
* Lamina propria


* "1 Kierszenbaum, AL. Histology and Cell Biology: An Introduction to Pathology. Mosby, Inc, MO: 2002. Chapter 4."

Wikimedia Foundation. 2010.

Игры ⚽ Нужно решить контрольную?

Look at other dictionaries:

  • basal lamina — n 1) the part of the gray matter of the embryonic neural tube from which the motor nerve roots arise 2) a thin extracellular layer composed chiefly of collagen, proteoglycans, and glycoproteins (as laminin and fibronectin) that lies adjacent to… …   Medical dictionary

  • basal lamina — (PORIFERA) The attachment surface …   Dictionary of invertebrate zoology

  • basal lamina — See basement membrane …   Dictionary of molecular biology

  • basal lamina — noun : the part of the gray matter of the embryonic neural tube from which the motor nerve roots arise …   Useful english dictionary

  • basal lamina of choroid — l. basalis choroideae …   Medical dictionary

  • basal lamina of ciliary body — l. basalis corporis ciliaris …   Medical dictionary

  • basal lamina of cochlear duct — l. basilaris ductus cochlearis …   Medical dictionary

  • Lamina — may refer to:*Lamina of the vertebral arch *Planar lamina, a two dimensional planar closed surface with mass and density, in mathematics *A thin plate, sheet or layer, such as: **Lamina (algae), a structure in seaweeds **the basal lamina, a… …   Wikipedia

  • Basal — is a term with several scientific meanings:*A basal clade is one which forms an outgroup to a larger clade. As such the term is relative. *Basal (medicine) refers to a type of insulin dosing. *The basal ganglia are a region of the brain. *The… …   Wikipedia

  • Basal plate (neural tube) — Infobox Embryology Name = Basal plate Latin = Lamina basalis, basal lamina GraySubject = 184 GrayPage = 735 Caption = The basal plate (basal lamina) is separated from the alar plate (alar lamina) by the sulcus limitans (unlabeled). Width = 200… …   Wikipedia

Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”