Hialino

Hialino, or hyaline in English, is a descriptor used in histology, pathology, and related medical fields to indicate a glassy, translucent, and homogeneous appearance of tissue or deposits. The term derives from the Greek hyalos, meaning glass, and is applied to describe materials that are eosinophilic and structureless under light microscopy.

In anatomy and physiology, hialino describes a normal connective tissue type known as hyaline cartilage. This cartilage has a glossy, bluish-white matrix and covers articular surfaces in joints, the ends of ribs, the nose, trachea, and larynx. It is rich in type II collagen and proteoglycans, providing smoothness and support with a relatively low propensity for calcification.

In pathology, hialino denotes a process or material that appears homogeneously glassy. Hyalinization or hyaline change refers to the replacement of normal tissue by a pink, eosinophilic, acellular material, often proteinaceous. This can occur in various organs, producing conditions such as hyaline arteriolosclerosis (thickened, glassy arterial walls commonly seen with aging and diabetes) or hyaline deposits in glomeruli. Hyaline membranes, composed of fibrin and necrotic debris, can line alveolar spaces in certain forms of lung injury, notably neonatal RDS. In the brain and other tissues, small hyaline bodies can be described as corpora hialina (hyaline inclusions), which may be seen with aging or certain diseases.

The term hialino thus spans both normal anatomy (hyaline cartilage) and pathological contexts where tissue or deposits take on a characteristic glassy, eosinophilic, homogeneous appearance.