bone question/anatomy?

Question

Johnny fractured the lower third of his right tibia in a skiing accident?
Johnny fractured the lower third of his right tibia in a skiing accident. The soft tissues in the area were severly damaged, and their surgical removal was necessary. After prolonged immobilization, it was found that Johnny was healing poorly. The exp. given by the ortho Surgeon was that the vascularization of the fracture site was still inadequate, and good healing was absolutely dependent upon an adequate blood supply. Describe how a long bone receives its blood supply, and trace the path of nutrient delivery to the osteocytes!!!!!!

I have not been able to find an answer to this.
Does anyone know??
Any help would be appreciated! If you could steer me in the right direction?

Answer 1

Osteocytes--mature bone cells derived from osteoblasts. These are the principal cells of bone tissue. These cells are formed when osteoblast cells are trapped by the matrix that they secrete. Osteocytes, however, no longer secrete matrix materials. Osteocytes maintain daily functions of bone tissue (nutrient and waste exchange, for instance).

COMPACT BONE TISSUE:


Compact bone contains fewer spaces. It forms the external layer of all bones, and the bulk of the diaphysis of long bones.
Compact bone provides protection and support and helps the long bones resist the stress of weight placed upon them.
Compact bone has a Concentric-ring arrangement of the matrix material.
Blood vessels, lymphatic vessels, and nerves penetrate compact bones through Perforating Canals (Volkmann’s Canals). Blood vessels and nerves of these canals connect with those of the medullary cavity, periostium, and Central Canals (Haversian Canals).
The Central Canals run longitudinally through the bone and are surronded by concentric Lamellae.
Small spaces between the lamellae are called the Lacunae, and contain the Osteocytes.
Radiating out from the lacunae are the Canaliculi (small canals). These canals are filled with extracellular fluid and contain cytoplasmic extensions of the Osteocytes.
The branching canaliculi provide a route for dispersal of nutrients into the bone tissue. Oseocytes from neighboring canaliculi also form gap junctions for exchange of nutrients.
An Osteon (the basic unit of compact bone) consists of a central canal (Haversian canal) with its surrounding lacunae and canaliculi.

SPONGY BONE TISSUE:


Spongy bone does not contain true osteons. Instead, it consists of lamellae arranged in irregular plates called Trabeculae. The spaces between trabeculae are filled with red bone marrow in some bones (red bone marrow produces red blood cells).
Oseteocytes are found in the lacunae and canaliculi radiate out from the lacunae.
Osteocytes receive nourishment directly from blood circulating through the marrow cavities.
Osteons are not necessary because osteocytes are not deeply buried in matrix materials.
Spongy bone makes up most material of short, flat, and irregular bones, and forms most of the epiphyses of long bones.
Spongy bone tissue in the hipbones, ribs, breastbone, backbones, skull, and ends of some long bones is the only site of red bone marrow storage and Hemopoiesis (red blood cell production) in adults.