Why nerve impulses travel faster in medullated nerve fibres?

Explanation

### Step-by-Step Text Solution:

1. **Understanding Nerve Fibers**: Nerve fibers can be classified into two types: medullated (myelinated) and non-medullated (unmyelinated). Medullated fibers have a myelin sheath surrounding them, while non-medullated fibers do not.

2. **Role of Myelin Sheath**: The myelin sheath acts as an insulating layer around the nerve fibers. This insulation is crucial because it prevents the loss of electrical impulses as they travel along the nerve.

3. **Node of Ranvier**: Between segments of the myelin sheath, there are gaps known as the Nodes of Ranvier. These nodes are critical for the propagation of nerve impulses.

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