The structures that contain grey matter and white matter are found in the

1. Analyze the question The question asks which body system contains structures made of grey matter and white matter.

2. Explain the concept Grey matter and white matter are tissues of the central nervous system (CNS), which is made up of the brain and spinal cord.

• Grey matter: contains mainly the cell bodies of neurons, dendrites, and synapses. It is responsible for processing information.
• White matter: contains mainly myelinated nerve fibres (axons). The fatty myelin sheath gives it its whitish colour. It carries impulses between different regions.

Their arrangement differs by organ:

• Brain: grey matter is on the outside (cortex) and white matter is inside.
• Spinal cord: white matter is on the outside and grey matter is inside, in a butterfly or H shape.

3. Solution

• A. Reproductive system: contains gonads, ducts, and glands, with no grey or white matter. ✗
• B. Nervous system: the brain and spinal cord contain both grey and white matter. ✓
• C. Respiratory system: lungs, trachea, and bronchi, with no grey or white matter. ✗
• D. Digestive system: the alimentary canal and its associated glands. ✗

4. Answer The correct option is B. nervous system.

5. Exam tip Remember: "Grey = Gathering of cell bodies; White = Wires (myelinated axons)." Whenever you see "grey matter" or "white matter" in an exam, think brain and spinal cord, which means the nervous system.