What is the functional significance of the periosteum in a long bone?

Explanation

### Step-by-Step Text Solution:

1. **Definition of Periosteum**: The periosteum is a thin membrane that covers the outer surface of long bones, except for the articular surfaces (joints).

2. **Protection**: One of the primary functions of the periosteum is to provide protection to the underlying bone. It acts as a barrier against physical damage and infection.

3. **Blood and Nutrient Supply**: The periosteum is rich in blood vessels and nerves. It plays a crucial role in supplying blood and nutrients to the bone tissue, which is essential for maintaining bone health and function.

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