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Reticular CT

Reticular connective tissue is a type of connective tissue. It is characterized by a unique network-like structure composed of reticular fibers. These fibers create a network for lymphocytes. (Like you couldn’t figure that out yourself.)

Microscopic image of lymph node tissue stained with silver. Dark brown/black reticular fibers form a net-like structure interspersed with densely packed purple lymphocytes. The reticular fiber network dominates the midground, with dispersed lymphocytes filling the texture. Focus appears sharp, typical of histology slides. Illumination from behind is mostly even, creating high contrast with the reticular fibers.
Figure 1: Lymph node tissue, silver stain showing reticular fibers and lymphocytes.

Cells

Reticular cells are specialized fibroblast-like cells found within the reticular network. These cells produce and maintain the reticular fibers and extracellular matrix of the tissue. Also trapped in the reticular fibers are immune cells such as macrophages and lymphocytes.  

Fibers

Reticular fibers are thin, branching fibers made primarily of type III collagen. These darkly-stained fibers are thinner than collagen fibers found in other connective tissues. They often form a mesh-like framework that supports other cells and structures.  The open network structure allows for the movement of lymphocytes, macrophages, and other immune cells through the tissue. This structure facilitates interactions among the cells.

Matrix

The ground substance of reticular tissue is a gel-like matrix composed of glycoproteins, proteoglycans, and water. This ground substance fills the spaces between reticular fibers. It provides a fluid that slowly enters and drains through the area.

Functions

Reticular tissue forms a supportive framework or scaffolding for lymphoid organs. These organs include the spleen, lymph nodes, and bone marrow. It provides support for immune cells and blood vessels within these organs. The mesh-like network of reticular fibers in reticular tissue acts as a filter. It traps and immobilizes various cells, pathogens, and foreign particles that pass through the tissue. This function is crucial in lymphoid organs. Reticular tissue helps filter and remove foreign substances from the lymphatic fluid. It also cleanses the blood.

Locations

Reticular connective tissue is primarily found in lymphoid organs, including the lymph nodes, spleen, bone marrow, and thymus gland. It forms the stroma or supportive framework of these organs, providing structural integrity and support for immune cell populations.

Easily Confused With

Blood

High-magnification histological image of a lymph node with reticular CT, silver stained. The image is densely packed with dark purple lymphocyte clusters interspersed with a network of black reticular fibers. The background appears off-white. The overall composition is cellular, with a focus on structural elements within the lymph node.
Figure 2: Silver-stained lymph node showing reticular fibers and lymphocyte clusters.

Figure 1: Lymph node, stained with silver to show reticular fibers Slide 28-2
Figure 2: Lymph node, stained with silver to show reticular fibers Slide 28-2
All by University of Michigan Histology, licensed under CC BY-NC-SA 3.0.

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General Information
Adipose CT
Areolar CT
Reticular CT
Dense Regular CT
Dense Irregular CT
Elastic CT
Bone CT
Hyaline Cartilage CT
Elastic Cartilage CT
Fibrocartilage CT

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