What is responsible for the difference in colour between the grey horns and the white columns? 2. The white columns contain both ascending and descending tracts. a. Do ascending tracts carry sensory or motor info? b. Do descending tracts carry sensory or motor info? 3. What type of fluid is found in the subarachnoid space? 4. During labour, women are sometimes given an “epidural”. What is it and why is it administered into the epidural space? 5. During a spinal tap. a large needle is inserted into the spine to draw CSF for testing. a. Where along the spine is this needle inserted and why is this location preferred? b. How deeply must the needle be inserted into what area of the meninges)?