Context: The pain signal travels from the periphery to the spinal cord along an A-delta or C fiber. Because the A-delta fiber is thicker than the C fiber, and is thinly sheathed in an electrically insulating material (myelin), it carries its signal faster (5–30 m/s) than the unmyelinated C fiber (0.5–2 m/s). Pain evoked by the (faster) A-delta fibers is described as sharp and is felt first. This is followed by a duller pain, often described as burning, carried by the C fibers. These first order neurons enter the spinal cord via Lissauer's tract.

Question: How does the pain signal travel from the periphery to the spinal cord?
Answer: along an A-delta or C fiber

Question: Which fiber is thicker?
Answer: A-delta

Question: What is the electrically insulting material that sheaths a-delta fiber?
Answer: myelin

Question: What is pain evoked by a-delta fibers described as?
Answer: sharp and is felt first

Question: How do first order neurons enter the spinal cord?
Answer: via Lissauer's tract

Question: What travels along a C-delta or A fiber?
Answer: Unanswerable

Question: What is the name for an insulating material?
Answer: Unanswerable

Question: What is evoked by the faster C deltas?
Answer: Unanswerable

Question: What do A fibers carry?
Answer: Unanswerable