Vävnaden

Vävnaden, in biology, refers to the tissue, the organized assembly of cells that forms the structure of organs and other body parts. The definite form Vävnaden is the Swedish term for tissue as a class. Tissues are composed of specialized cells embedded in an extracellular matrix that provides mechanical support and biochemical cues essential for function.

There are four basic tissue types: epithelial tissue lines surfaces and forms glands, protecting underlying structures and regulating exchange. Connective tissue supports, binds, and protects organs; it includes bone, cartilage, fat, blood, and tendons. Muscle tissue enables movement through contraction, and nervous tissue transmits electrical signals to coordinate activities.

Structure and composition: Most tissues combine cellular components with an extracellular matrix rich in proteins such as collagen and elastin, as well as proteoglycans. The ECM varies in density and rigidity, influencing tissue function. Tissues are usually vascularized and innervated to varying degrees, depending on type.

Development and repair: In embryos, tissues derive from the three germ layers, with stem and progenitor cells maintaining turnover in adults. When damaged, tissues initiate inflammatory and reparative processes that may restore function or, in some cases, lead to scar formation. Histology studies examine tissue architecture using microscopy and specialized stains.