Basal lamina
From WikiLectures
Basal lamina is a layer of extracellular material separating epithelial tissue from connective tissue. The thickness of the basal lamina is 30-100 nm.
Function[edit | edit source]
- This is a selective barrier between epithelial and connective tissue that is important for the interaction, placement and orientation of epithelial cells.
- If it is disturbed, there is invasion of epithelial cells into connective tissue (in cancers) or vice versa (e.g. in the growth of blood vessels).
- The basal lamina may contain pores where functional communication between the two tissues is needed (e.g. intestinal villi, Peyer's patches).
Construction[edit | edit source]
It contains two layers:
- Lamina lucida
- A light layer that adheres to the base of the epithelial cell.
- It is attached to cells by hemidesmosomes and anchoring filaments (molecules of integral membrane proteins integrins).
- It consists mainly of laminin.
- Lamina densa - electron-dense layer 20-90 nm thick.
- It has a felt-like character.
- The lamina reticularis is connected to the lamina dense by a system of anchoring fibrils.
- The lamina densa consists mainly of collagen type IV.
Lamina reticularis - a thin layer of reticular fibers and microfibrils of elastic fibers.
- Lamina reticularis is a product of fibrous tissue cells.
- It consists of:
- collagen III (reticular fibers),
- collagen VII (anchoring fibrils),
- fibrillin (microfibrils of elastic fibers).
The term basal lamina is often confused with the term basement membrane. Basal membrane = lamina basalis + lamina reticularis.
- In the light microscope we do not see the basal lamina, but the basement membrane.
Links[edit | edit source]
Related Articles[edit | edit source]
References[edit | edit source]
- VAJNER, Ludek – UHLÍK, George – KONRÁDOVÁ, Václava. Medical Histology. 1, Cytology and General Histology. 1st edition. Karolinum, 2010. 112 pp. ISBN 978-80-246-1860-9.
