blood-brain barrier morphology trait Any measurable or observable characteristic related to the shape, structure, color or pattern of the group of barriers and transport systems in the brain capillary endothelium that controls the entrance of substances into the brain extracellular space from the blood. CMO:0003170 Trait.ontology CMO:0003174 VT:0000075 CMO:0003183 CMO:0003177 CMO:0003186 blood vessel morphology trait