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The internal elastic lamina or internal elastic lamella is a layer of elastic tissue that forms the outermost part of the tunica intima of blood vessels. It separates tunica intima from tunica media.


Histology

It is readily visualized with light microscopy in sections of muscular arteries, where it is thick and prominent, and arterioles, where it is slightly less prominent and often incomplete. It is very thin in veins and venules. In
elastic arteries An elastic artery (conducting artery or conduit artery) is an artery with many collagen and elastin filaments in the tunica media, which gives it the ability to stretch in response to each pulse. This elasticity also gives rise to the Windkessel ...
such as the aorta, which have very regular elastic laminae between layers of
smooth muscle Smooth muscle is an involuntary non-striated muscle, so-called because it has no sarcomeres and therefore no striations (''bands'' or ''stripes''). It is divided into two subgroups, single-unit and multiunit smooth muscle. Within single-unit mus ...
cells in their tunica media, the internal elastic lamina is approximately the same thickness as the other elastic laminae that are normally present.http://www.ouhsc.edu/histology/text%20sections/cardiovascular.html There is small amount of subendothelial connective tissue between
basement membrane The basement 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. The basement membrane sits between Epithelium, epithelial tissues including mesot ...
of endothelial cells and internal elastic lamina. Reduplication of internal elastic lamina can be seen in elderly individuals due to
intimal fibroplasia The tunica intima (New Latin "inner coat"), or intima for short, is the innermost tunica (layer) of an artery or vein. It is made up of one layer of endothelial cells and is supported by an internal elastic lamina. The endothelial cells are in ...
, which is part of the
aging Ageing ( BE) or aging ( AE) is the process of becoming older. The term refers mainly to humans, many other animals, and fungi, whereas for example, bacteria, perennial plants and some simple animals are potentially biologically immortal. In ...
process.


Associated pathologic conditions

*Damage in Giant cell arteritis leads to microaneurysms. Demonstration of fragmentation in this layer by elastin-
van Gieson Van Gieson's stain is a mixture of picric acid and acid fuchsin. It is the simplest method of differential staining of collagen and other connective tissue. It was introduced to histology by American neuropsychiatrist and pathologist Ira Van ...
stain aids in diagnosis of giant cell arteritis. It stains
muscle Skeletal muscles (commonly referred to as muscles) are organs of the vertebrate muscular system and typically are attached by tendons to bones of a skeleton. The muscle cells of skeletal muscles are much longer than in the other types of muscl ...
tissue in yellow,
connective tissue Connective tissue is one of the four primary types of animal tissue, along with epithelial tissue, muscle tissue, and nervous tissue. It develops from the mesenchyme derived from the mesoderm the middle embryonic germ layer. Connective tiss ...
in red and elastic structures (like internal elastic lamina) in black color. * In
chronic allograft nephropathy Chronic allograft nephropathy (CAN) is a kidney disorder which is the leading cause of kidney transplant failure, occurring months to years after the transplant. Symptoms and signs CAN is characterized by a gradual decline in kidney function and, ...
, disruption or reduplication of internal elastic lamina can be observed, which causes narrowing of the lumen and downstream ischemia. * In fungal rhinosinusitis, the organism has predilection for internal elastic lamina during phase of spread.


References

Angiology {{circulatory-stub