Epithelial tissues are specialized for protection, absorption, and secretion. Epithelium can be stratified or simple. Pseudostratified epithelium appears layered but is not. Gland cells can be found within epithelium lining a cavity. Tight junctions form an impermeable barrier between cells.
Gap junctions allow exchange through pores between cells.
Adhesion junctions are formed by intercellular filaments. Connective tissue supports, protects, provides frameworks, fills spaces, stores fat, and produces blood cells. A matrix that varies from solid to fluid separates connective tissue cells. Loose connective tissue binds structures together and can be found between epithelial layers. Fibroblasts are suspended in a jellylike matrix containing both collagen and elastic fibers.