retikulära

Retikulära, or reticular, is a term used in biology and medicine to describe net-like, mesh-shaped structures and networks. The word derives from Latin reticulum, meaning a small net, and is applied to tissues, cells or organelles that form an interconnected framework.

In connective tissue, reticular tissue consists mainly of reticular fibers made of type III collagen. These fibers form a delicate, supportive mesh that provides the stroma for organs such as lymph nodes, the spleen, liver and bone marrow. Reticular cells, a type of fibroblast, secrete the extracellular matrix and fibers, creating a scaffold that supports parenchymal cells and facilitates the passage of immune cells. The reticular network is often highlighted in histology by silver-based reticulin stains; disruptions or expansion of the reticular framework can be involved in diseases such as fibrosis or cirrhosis.

In cell biology, the term describes the reticulum, a vast intracellular network of membranous tubules and sacs. The endoplasmic reticulum comprises rough ER, with ribosomes for protein synthesis, and smooth ER, involved in lipid metabolism and detoxification. The ER network is continuous with the outer nuclear envelope and extends throughout the cytoplasm, playing a critical role in protein folding, quality control, lipid synthesis and calcium storage.

In neuroscience, the reticular formation is a complex network of interconnected nuclei in the brainstem that participates in arousal, attention, sleep-wake regulation and autonomic functions. It modulates sensory filtering and consciousness and connects with many brain regions.

See also reticular tissue, reticulin, endoplasmic reticulum, and reticular formation.