Final answer:
The blood-brain barrier is composed of epithelial cells and one component of it is the basement membrane or basal lamina, which provides strength and flexibility while binding the endothelium to the underlying connective tissue.
Step-by-step explanation:
True. The blood-brain barrier is a highly selective membrane that separates circulating blood from the extracellular fluid in the brain and spinal cord. It is composed of epithelial cells and one component of the blood-brain barrier is the basement membrane, also known as the basal lamina. The basement membrane provides strength while maintaining flexibility and acts as a thin extracellular layer that binds the endothelium (lining of the blood vessels) to the underlying connective tissue.