Question

question
type your response in the box.
multiple sclerosis (ms) is a disease that affects the nerve cells of the brain and the spinal cord. some of the symptoms of ms are chronic pain, pins-and-needles sensations, muscle weakness, and visual disturbances. study the image, and then explain the cause for these symptoms.
healthy nerve
nerve affected by ms

Explanation:

The problem is about Multiple Sclerosis (MS) affecting nerve cells. The healthy nerve has a myelin sheath (insulating layer) and the MS - affected nerve has damaged myelin. Myelin's role is to speed up nerve impulse transmission. When myelin is damaged (as in MS, due to the immune system attacking it), nerve impulses are disrupted.

• Chronic pain, pins - and - needles sensations: Disrupted sensory nerve impulses cause abnormal sensory perceptions.
• Muscle weakness: Motor nerve impulses (controlling muscles) are disrupted, so muscles don't receive proper signals to contract/function, leading to weakness.
• Visual disturbances: Optic nerve (part of CNS) myelin damage disrupts visual signal transmission from eyes to brain.

Answer:

Multiple Sclerosis (MS) damages the myelin sheath around nerve cells (seen in the image: healthy nerve has intact myelin, MS - affected has damaged myelin). Myelin speeds nerve impulse transmission. When myelin is damaged (due to immune - mediated destruction), nerve impulses are disrupted.

• Chronic pain, pins - and - needles: Disrupted sensory nerve impulses cause abnormal sensory signals (e.g., misfiring, slowed/blocked signals), leading to these sensations.
• Muscle weakness: Motor nerve impulses (controlling muscle movement) are disrupted, so muscles don't get proper activation signals, causing weakness.
• Visual disturbances: Optic nerve myelin damage disrupts visual signal transmission from the eye to the brain, impairing vision.