Chapter 5 - The Skeletal System: Osseous Tissue and Skeletal Structure


Chapter Outline
Introduction
Structure of Bone
Bone Development and Growth

Terms – Be able to define each of the terms listed below. They are listed in the order in which they appear in the chapter:

  • osseous tissue
  • hydroxyapatite
  • osteocyte
  • lacunae
  • lamellae
  • canaliculi
  • osteoblasts
  • osteogenesis
  • osteoprogenitor cell
  • osteoclast
  • compact bone
  • spongy bone
  • marrow cavity
  • bone marrow
  • yellow marrow
  • red marrow
  • osteon
  • central canal
  • Haversian canal
  • perforating canal
  • trabeculae
  • epiphysis
  • diaphysis
  • metaphysis
  • periosteum
  • endosteum
  • ossification
  • calcification
  • intramembranous ossification
  • endochondral ossification


Notes

Test objectives are indicated by an asterisk (*).

Introduction
*Describe the functions of the skeletal system.

  • Support
  • Storage of Minerals and Lipids
  • Blood Cell Production
  • Protection
  • Leverage

Structure of Bone
Histological Organization
* Describe the components of the matrix of the bone and the function of each of these components.

The Matrix of Bone

  • Bone is a type of connective tissue (supporting connective tissue) and thus contains the components of cells and a matrix. (Click here to see the notes about connective tissue components.)
  • Calcium phosphate + calcium hydroxide = hydroxyapatite - provides compressional strength (hydroxyapatite is the ground substance of bone tissue.)
  • Collagen fibers – provide tensile strength, resistance to being stretched or torn apart.

The Cells of Bone
*
List the names of the types of bone cells and describe their functions.

  • Refer to Figure 5-1, page 113.
  • Osteoprogenitor cells
    • osteo = bone; pro = precursor; gen = to produce unspecialized cells that will differentiate into osteoblasts.
  • Osteoblasts
    • blast = germ, bud, precursor
    • Found on inner or outer surface of bones
    • Are the cells that form the bone; they secrete collagen and other organic components of bone tissue.
  • Osteoclasts
    • clast = to break
    • release enzymes that break down bone and release calcium and phosphate into the blood
    • this process is continual

Compact and Spongy Bone
* Compare the structure and functions of compact and spongy bone.

  • Refer to Figure 5-2, page 114.
  • Compact bone forms the walls; surrounds the marrow cavity which contains yellow marrow, which contain adipocytes. The marrow cavity may contain red marrow.

Structural Differences Between Compact and Spongy Bone

Compact Bone

Spongy Bone

  • trabeculae - network of struts or thin, branching plates
  • no osteons

Functional Differences Between and Compact and Spongy Bone

Compact bone

  • compact bone where stress is found in just a few directions
  • Parts of a long bone
    • epiphyses (plural) (epiphysis, singular) = ends of long bone
    • diaphysis = shaft of long bone
    • metaphysis = region where the diaphysis meets the epiphysis

Spongy bone


The Periosteum and Endosteum
*Locate and compare the structure and function of periosteum and endosteum.

  • See Figure 5-4, page 117.
  • Periosteum = the membrane the covers bone; is essential for bone growth, repair, and nutrition. Is continuous with the ligaments and tendons.
  • Endosteum = layer that lines the marrow cavity, covers the trabeculae, and lines the inner surface of the central canals of osteons. See Figure 5-4b, page 117 Go to perth.uwlax.edu/Biology/faculty/maher/skeleton/img009.jpg

Bone Development and Growth

Intramembranous Ossification
*
Define intramembranous ossification.

  • Intramembranous ossification is the process in which bone is formed directly in membranous tissue. It typically occurs for the formation of flat bones.

Endochondral Ossification
*
Define endochondral ossification.

  • Endochondral ossification is the process of replacing cartilage with bone.
  • See Figure 5-7, page 120.