What are Lamellae? Where are they present ?

Explanation

### Step-by-Step Solution:

1. **Definition of Lamellae**:
- Lamellae are defined as concentric layers that appear as alternating bright and dark rings. This unique appearance is due to the specific arrangement of collagen fibers within these layers.

2. **Structure of Lamellae**:
- Within each concentric layer, the collagen fibers are arranged parallel to one another. However, in adjacent layers, these fibers are oriented perpendicularly, either forward or backward. This alternating arrangement contributes to the distinct bright and dark appearance of the lamellae.

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