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 ...
with a network of
reticular fiber
Reticular fibers, reticular fibres or reticulin is a type of fiber in connective tissue composed of type III collagen secreted by reticular cells. Reticular fibers crosslink to form a fine meshwork (reticulin). This network acts as a supportin ...
s, made of
type III collagen
Type III Collagen is a homotrimer, or a protein composed of three identical peptide chains (monomers), each called an alpha 1 chain of type III collagen. Formally, the monomers are called collagen type III, alpha-1 chain and in humans are encoded ...
(''
reticulum
Reticulum is a small, faint constellation in the southern sky. Its name is Latin for a small net, or reticle—a net of crosshairs at the focus of a telescope eyepiece that is used to measure star positions. The constellation is best viewed b ...
'' = net or network). Reticular fibers are not unique to reticular connective tissue, but only in this type they are dominant.
Reticular fibers
Reticular fibers, reticular fibres or reticulin is a type of fiber in connective tissue composed of type III collagen secreted by reticular cells. Reticular fibers crosslink to form a fine meshwork (reticulin). This network acts as a supportin ...
are synthesized by special
fibroblasts
A fibroblast is a type of biological cell that synthesizes the extracellular matrix and collagen, produces the structural framework ( stroma) for animal tissues, and plays a critical role in wound healing. Fibroblasts are the most common cells o ...
called
reticular cells
A reticular cell is a type of fibroblast that synthesizes collagen alpha-1(III) and uses it to produce reticular fibers. The cell surrounds the fibers with its cytoplasm, isolating them from other tissue components and cells. Reticular cells pro ...
. The fibers are thin branching structures.
Location
Reticular connective tissue is found around the kidney, liver, the spleen, and lymph nodes, Peyer' patches as well as in bone marrow.Martini, Frederic H. Fundamentals of Anatomy and Physiology. Seventh Edition. Pearson Benjamin Cummings. United States. 2006.
Function
The fibers form a soft skeleton ( stroma) to support the
lymphoid organs
The lymphatic system, or lymphoid system, is an organ system in vertebrates that is part of the immune system, and complementary to the circulatory system. It consists of a large network of lymphatic vessels, lymph nodes, lymphatic or lymphoid ...
(
lymph node
A lymph node, or lymph gland, is a kidney-shaped organ of the lymphatic system and the adaptive immune system. A large number of lymph nodes are linked throughout the body by the lymphatic vessels. They are major sites of lymphocytes that inclu ...
spleen
The spleen is an organ found in almost all vertebrates. Similar in structure to a large lymph node, it acts primarily as a blood filter. The word spleen comes .
).
Adipose tissue
Adipose tissue, body fat, or simply fat is a loose connective tissue composed mostly of adipocytes. In addition to adipocytes, adipose tissue contains the stromal vascular fraction (SVF) of cells including preadipocytes, fibroblasts, vascular e ...
is held together by reticular fibers.
Staining
They can be identified in
histology
Histology,
also known as microscopic anatomy or microanatomy, is the branch of biology which studies the microscopic anatomy of biological tissues. Histology is the microscopic counterpart to gross anatomy, which looks at larger structures vis ...
silver
Silver is a chemical element with the Symbol (chemistry), symbol Ag (from the Latin ', derived from the Proto-Indo-European wikt:Reconstruction:Proto-Indo-European/h₂erǵ-, ''h₂erǵ'': "shiny" or "white") and atomic number 47. A soft, whi ...
or the
PAS stain
PAS or Pas may refer to:
Companies and organizations
* Pakistan Academy of Sciences
* Pakistan Administrative Service
* Pan Am Southern, a freight railroad owned by Norfolk Southern and Pan Am Railways
* Pan American Silver, a mining company i ...
that stains
carbohydrates
In organic chemistry, a carbohydrate () is a biomolecule consisting of carbon (C), hydrogen (H) and oxygen (O) atoms, usually with a hydrogen–oxygen atom ratio of 2:1 (as in water) and thus with the empirical formula (where ''m'' may or may ...
.
Gordon and Gold can also be used.
Appearance
Reticular connective tissue resembles areolar connective tissue, but the only fibers in its matrix are reticular fibers, which form a delicate network along which fibroblasts called reticular cells lie scattered. Although reticular fibers are widely distributed in the body, reticular tissue is limited to certain sites. It forms a labyrinth-like stroma (literally, "bed or "mattress"), or internal framework, that can support many free blood cells (largely lymphocytes) in lymph nodes, the spleen, and red bone marrow.
Classification
There are more than 20 types of reticular fibers. In Reticular Connective Tissue type III collagen/reticular fiber (100-150 nm in diameter) is the major fiber component. It forms the architectural framework of liver, adipose tissue, bone marrow, spleen and basement membrane, to name a few.
See also
*
Deiters cells
Deiters' cells, also known as outer phalangeal cells or cells of Deiters (), are a cell type found within the inner ear. They contain both micro-filaments and micro-tubules which run from the basilar membrane to the reticular membrane of the in ...