Page 284 - Atlas of Histology with Functional Correlations

SECTION 2 • Bone

CHARACTERISTICS OF BONE

Consists of cells, connective tissue fibers, and extracellular material
Mineral deposits in the bone matrix produce a hard structure for protecting

various organs
Functions in hematopoiesis and as reservoir for calcium and minerals

BONE MICROARCHITECTURE

All bones exhibit similar histology; there are two types of bones
Compact bone is the outer cylindrical part of long bone

Inner bone adjacent to bone marrow is the cancellous (spongy) bone
In newborn bones, marrow is red and hematopoietic; in adults, the marrow of
long bone is yellow and does not function in hematopoiesis
Outer circumferential lamellae are located deep to the periosteum

Inner circumferential lamellae are located around the bone marrow
Concentric lamellae form osteons in compact bone and surround the central
canal
Most osteons are oriented in the long axis of the bone

BONE TYPES

Orientation of collagen fibers indicates bone type

Compact and cancellous bones show similar microscopic structure
Woven (immature) bone has a random orientation of collagen fibers and is
nonlamellar

Woven bone is seen during fetal bone development and bone repair
Lamellar (mature) bone with concentric lamellae around the central canal is
in adults
In lamellar bone, collagen fibers exhibit parallel arrangements that follow a

283