Basement membrane

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Basement membrane
The epithelium and endobasement membrane in relation to epithelium and endothelium. Also seen are other extracellular matrix components
Image showing the basement membrane of the lining of the mouth, which separates the lining (epithelium) from a loose layer of connective tissue (the lamina propria)
Details
Identifiers
Latinmembrana basalis
MeSHD001485
THH2.00.00.0.00005
FMA63872
Anatomical terms of microanatomy
Not to be confused with Basilar membrane.

The basement membrane, also known as base membrane, is a thin, pliable sheet-like type of extracellular matrix that provides cell and tissue support and acts as a platform for complex signalling.[1][2] The basement membrane sits between epithelial tissues including mesothelium and endothelium, and the underlying connective tissue.[3][4]

Structure

Normal histology of the breast, with basement membrane annotated near center-right.
Prostate gland microanatomy, with basement membrane annotated at bottom.

As seen with the

collagen VII anchoring fibrils and fibrillin microfibrils.[5]

The basal lamina layer can further be subdivided into two layers based on their visual appearance in electron microscopy. The lighter-colored layer closer to the epithelium is called the

entactins, and dystroglycans. Integrins are a key component of hemidesmosomes
which serve to anchor the epithelium to the underlying basement membrane.

To represent the above in a visually organised manner, the basement membrane is organized as follows:

Function

The primary function of the basement membrane is to anchor down the epithelium to its loose connective tissue (the dermis or lamina propria) underneath. This is achieved by cell-matrix adhesions through substrate adhesion molecules (SAMs).

The basement membrane acts as a mechanical barrier, preventing

malignant cells from invading the deeper tissues.[7] Early stages of malignancy that are thus limited to the epithelial layer by the basement membrane are called carcinoma in situ
.

The basement membrane is also essential for

endothelial cells.[8]

The most notable examples of basement membranes is the

capillaries, by the fusion of the basal lamina of the lung alveoli and of the basal lamina of the lung capillaries, which is where oxygen and CO2 diffusion occurs (gas exchange
).

As of 2017, other roles for basement membrane include blood filtration and muscle homeostasis.[1] Fractones may be a type of basement membrane, serving as a niche for stem cells.[10][11]

Clinical significance

Some diseases result from a poorly functioning basement membrane. The cause can be genetic defects, injuries by the body's own immune system, or other mechanisms.[12] Diseases involving basement membranes at multiple locations include:

In

systemic lupus erythematosus or dermatomyositis in the skin, or collagenous colitis in the colon.[15]

Evolutionary origin

These are only found within

homoscleromorphic
sponge animals. The homoscleromorph were found to be sister to diploblasts in some studies, making the membrane originate once in the history of life. But more recent studies have disregarded diploblast-homoscleromorph group, so other sponges may have lost it (most probable) or the origin in the two groups may be separate.

See also

References

  1. ^
    PMID 28040522
    .
  2. PMID 29853176
    .
  3. ISBN 978-0-323-07842-9
    .
  4. ^
    ISBN 9780470646083
    .
  5. PMID 1309319. Archived
    from the original on 2007-10-13.
  6. PMID 1744087
    .
  7. S2CID 4356057
    .
  8. PMID 3049626
    .
  9. ^ "Sect. 7, Ch. 4: Basement Membrane". Renal Physiology Glomerular Filtration Rate and Renal Blood Flow. Medical College of Georgia, Robert B. Greenblatt, M.D. Library. 1 April 2008. Archived from the original on 1 April 2008. Retrieved 7 May 2018.{{cite book}}: CS1 maint: bot: original URL status unknown (link)
  10. S2CID 19919800
    .
  11. PMID 30379609
    .
  12. ^ Henig RM (February 22, 2009). "What's Wrong With Summer Stiers?". New York Times. Archived from the original on November 9, 2016.
  13. ISBN 978-0-8153-3642-6
    .
  14. S2CID 221861310
    .
  15. PMID 11048985
    .

Further reading
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