Bone: the tissue
This cross section through a developing bone shows both lamellar and woven bone. The central portion is composed of circular osteons mixed with areas of woven bone. The bone at the edges is formed by flattened lamellae that cover the outer surface of the bone (right) and lining the marrow cavity (left). The marrow cavity, containing a small portion of red marrow, is visible to the far left. The marrow cavity is lined by an endosteum. Lamellae are difficult to distinguish in this decalcified bone tissue. 200x
Osteocytes >
Osteocytes are visible throughout this tissue and their pattern of distribution is a good indicator of the type of bone in which they are located.
Woven bone >
Areas of woven bone are still present in the center of this image, displaying a more amorphous structure. The osteocytes are rounder compared to lamellar bone.
Lamellar bone >
Concentrically arranged lamellae form osteons in the central region of the bone. The surfaces are covered or lined by flattened lamellae that are arranged circumferentially. In lamellar bone, osteocytes are more flattened, located between lamellae.
- Osteons
Concentrically arranged lamellae form osteons in the central region of the bone. The surfaces are covered or lined by flattened lamellae that are arranged circumferentially. In lamellar bone, osteocytes are more flattened, located between lamellae.
- - Haversian canals
Concentrically arranged lamellae form osteons in the central region of the bone. The surfaces are covered or lined by flattened lamellae that are arranged circumferentially. In lamellar bone, osteocytes are more flattened, located between lamellae.
- Circumferential lamellae >
The exterior of the bone is covered by outer circumferential lamellae (black arrow). The interior of the bone is lined by inner circumferential lamellae (green arrow). These lamellae are laid down by the periosteum and the endosteum, respectively.
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