What makes up the lamina densa?
The lamina densa consists of nonfibrilar collagen, in particular collagen IV, glycoproteins such as laminin, perlecan and nidogen, and proteoglycans. The reticular layer consists of collagens, including type III, and it consists of fibronectin, which are embedded in an amorphous proteoglycan-rich ground substance.
What is the difference between basal lamina and basement membrane?
Is there a difference between basal lamina & basement membrane? The basement membrane is the fusion of two lamina, the basal lamina and the reticular lamina (or lamina reticularis). The basal lamina is a layer of extracellular matrix secreted by the epithelial cells, on which the epithelium rests.
Is basement membrane acellular?
Basement membranes (BMs) are highly specialized extracellular matrices (sECMs) forming thin acellular layers that underlie cells and separate the cells from and connect them to their interstitial matrix [5]. The formation of BMs is a prerequisite for normal tissue development and function [6, 7].
Is basement membrane part of epithelium?
The basement membrane is form of extracellular matrix that underlies all epithelia. It provides structural support to epithelia and forms a mechanical connection between epithelia and underlying connective tissue.
What are basement membranes?
Basement membranes are thin layers of a specialized extracellular matrix that form the supporting structure on which epithelial and endothelial cells grow, and that surround muscle and fat cells and the Schwann cells of peripheral nerves.
What is alveolar basement membrane?
The alveolar basement membrane is dense and amorphous, has filaments in the lamina rara externa, and has discontinuities beneath type II pneumocytes, but not beneath type I pneumocytes, that allow penetration of cytoplasmic processes into the interstitium. FN is also found in basement membranes.
What is external lamina?
External lamina is a structure similar to basal lamina that surrounds the sarcolemma of muscle cells. It is secreted by myocytes and consists primarily of Collagen type IV, laminin and perlecan (heparan sulfate proteoglycan).
Where is the lamina lucida located in the body?
The lamina lucida is a component of the basement membrane which is found between the epithelium and underlying connective tissue (e.g., epidermis and dermis of the skin).
What kind of immunofluorescence is used in lamina lucida?
Immunofluorescence microscopy demonstrates IgG in the lamina lucida of the basement membrane. The target antigens are components of hemidesmosomes. These are the major attachment sites of epidermal basal cells and where cytoskeletal proteins link through the plasma membrane to the dermis.
Where does lamina lucida bind to anchoring fibrils?
It is possible that some filaments pass through the lamina densa and bind directly to anchoring fibrils in the sublamina densa region. 816 There are multiple antigens associated with the lamina lucida, particularly the anchoring filaments.
Is the junctional epithelium part of the lamina lucida?
Similarly, electron-lucent and electron-dense zones can be seen between enamel of teeth and the junctional epithelium. The electron-lucent zone is adjacent to the cells of the junctional epithelium and might be considered a continuation of the lamina lucida as both are seen to harbour hemidesmosomes.