connective tissue morphology trait basement membrane morphology trait Any measurable or observable characteristic related to the shape, structure, color, or pattern of the extracellular supportive tissue adjacent to the basal surface of the epithelia, including the epithelium of muscle cells, fat cells and Schwann cells; it is comprised of type IV collagen, laminin, and sulfated proteoglycans and other components and consists of two layers, the basal lamina and the lamina reticularis. Note: basal lamina and lamina reticularis (or of two basal laminae) compose the basement membrane. thus, in strict sense, the term basement membrane is different from and should not be confused with basal lamina. Trait.ontology VT:0004272