Areolært

Areolært, or areolar tissue, is a type of loose connective tissue that forms the flexible, supportive framework beneath many epithelia and around various organs. The term areolar comes from Latin areola, referring to the small spaces within its extracellular matrix, which gives the tissue its airy appearance. Histologically, areolært tissue consists of a loose network of collagen and elastic fibers embedded in a viscous ground substance, with numerous cells dispersed in the matrix.

The cellular composition includes fibroblasts as the primary resident cells, along with adipocytes, macrophages, plasma cells, mast cells, and various leukocytes. The extracellular matrix features a loose mesh of type I and III collagen fibers and elastic fibers, with ample interstitial fluid. The tissue is highly vascularized, facilitating diffusion of nutrients, gases, and waste between blood vessels and surrounding tissues.

Areolært tissue is widely distributed. It forms the lamina propria beneath mucosal epithelium, contributes to the superficial fascia, and lies in the papillary layer of the dermis beneath the epidermis. It also surrounds blood vessels, nerves, and glands, providing a flexible support network for surrounding structures.

Functions include binding and supporting other tissues, cushioning organs, nourishing avascular epithelia by diffusion, and participating in inflammatory responses and wound healing. Its loose structure allows rapid movement of interstitial fluid and quick communication between tissues.

Clinical notes: edema can develop when fluid accumulates in areolar spaces; the tissue can serve as a site for injections and may participate in inflammatory or fibrotic processes.