Reticular connective tissue
Textus reticularis
Also known as: reticular fibres, reticulin, type III collagen
A delicate three-dimensional network of thin reticular (type III collagen) fibres and reticular cells that forms the supporting stroma of lymphoid organs, bone marrow and the liver.
Overview
Reticular fibres are thin (≈0.5–2 µm), branched fibrils of type III collagen, coated with glycoproteins and proteoglycans. They do not stand out in H&E but are blackened by silver impregnation (argyrophilic) and are PAS-positive. They are produced by specialised fibroblasts called reticular cells, whose stellate processes wrap the fibres.
Reticular tissue forms a soft internal skeleton (stroma) for organs with many free cells: lymph nodes, spleen, bone marrow and the liver (in the space of Disse supporting the hepatocyte plates). Its open meshwork lets free cells (lymphocytes, macrophages, haematopoietic cells) and fluid move through while supporting them, and reticular cells help to guide immune-cell traffic. Reticular fibres also occur elsewhere: around adipocytes, smooth-muscle cells, nerve fibres and capillaries and in the reticular lamina of basement membranes. They are the first collagen laid down in wound healing (granulation tissue) and in the embryo, later largely replaced by type I collagen.
- Location
Lymph nodes, spleen, bone marrow, liver, tonsils; around adipocytes, muscle fibres, nerves and in basement membranes.
Anatomy
- Histology
Requires silver stains (fine black branching network) or PAS.
Function
- Supporting framework (stroma) for free cells in lymphoid and haematopoietic organs.
- Initial scaffold in wound healing.
Clinical significance
Vascular Ehlers–Danlos syndrome
COL3A1 mutations weaken type III collagen in vessels and hollow organs → spontaneous arterial, bowel and uterine rupture; thin translucent skin and easy bruising.
Myelofibrosis
Increased reticulin (and later collagen) fibrosis of the bone marrow in myeloproliferative neoplasms causes a "dry tap" on aspiration, teardrop red cells and extramedullary haematopoiesis.
Compiled from standard anatomy and physiology references — see the Cells & Tissues sources. For education only; not medical advice.