Question

1. compare the sympathetic and parasympathetic nervous systems.
2. why is the myelin sheath important for nerve conduction?
3. what role does the spinal cord play in the nervous system?

Explanation:

1. The sympathetic nervous system activates the "fight - or - flight" response, increasing heart rate, dilating pupils etc. The parasympathetic nervous system activates the "rest - and - digest" response, decreasing heart rate, promoting digestion.
2. The myelin sheath insulates axons, allowing for saltatory conduction which is faster than continuous conduction. It speeds up nerve impulse transmission.
3. The spinal cord serves as a major pathway for nerve signals between the brain and the rest of the body. It also controls some reflexes independently of the brain.

Answer:

1. The sympathetic nervous system is for "fight - or - flight", increasing heart rate etc.; the parasympathetic is for "rest - and - digest", decreasing heart rate etc.
2. It insulates axons and enables faster saltatory conduction of nerve impulses.
3. It is a nerve signal pathway between brain and body and controls some reflexes.