1. Bone Tissue Composition
Chapter 6

2. Bone Textures Compact bone Spongy (cancellous) bone Dense outer layer
Honeycomb of trabeculae found at the bone ends

3. Structure of a Long Bone
Diaphysis (shaft)
Compact bone collar surrounds medullary (marrow) cavity
Medullary cavity in adults contains fat (yellow marrow)

4. Structure of a Long Bone
Epiphyses
Expanded ends
Spongy bone interior
Epiphyseal line (remnant of growth plate)
Articular (hyaline) cartilage on joint surfaces

5. Articular cartilage Compact bone Proximal epiphysis Spongy bone
Epiphyseal
line
Periosteum
Compact bone
Medullary
cavity (lined
by endosteum)
(b)
Diaphysis
Distal
epiphysis
(a)
Figure 6.3a-b

6. Membranes of Bone Outer fibrous layer Inner osteogenic layer
Periosteum
Outer fibrous layer
Inner osteogenic layer
Osteoblasts (bone-forming cells)
Osteoclasts (bone-destroying cells)
Osteogenic cells (stem cells)
Nerve fibers, nutrient blood vessels, and lymphatic vessels enter the bone via nutrient foramina
Secured to underlying bone by Sharpey’s fibers

7. Membranes of Bone Endosteum
Delicate membrane on internal surfaces of bone
Also contains osteoblasts and osteoclasts

8. Endosteum Yellow bone marrow Compact bone Periosteum Perforating
(Sharpey’s) fibers
Nutrient
arteries
(c)
Figure 6.3c

9. Structure of Short, Irregular, and Flat Bones
Periosteum-covered compact bone on the outside
Endosteum-covered spongy bone within
Spongy bone called diploë in flat bones
Bone marrow between the trabeculae

10. Spongy bone
(diploë)
Compact
bone
Trabeculae
Figure 6.5

11. Location of Hematopoietic Tissue (Red Marrow)
Red marrow cavities of adults
Trabecular cavities of the heads of the femur and humerus
Trabecular cavities of the diploë of flat bones
Red marrow of newborn infants
Medullary cavities and all spaces in spongy bone

12. Microscopic Anatomy of Bone
Cells of bones
Osteogenic (osteoprogenitor) cells
Stem cells in periosteum and endosteum that give rise to osteoblasts
Osteoblasts
Bone-forming cells

13. (a) Osteogenic cell (b) Osteoblast Stem cell Matrix-synthesizing
cell responsible
for bone growth
Figure 6.4a-b

14. Microscopic Anatomy of Bone
Cells of bone
Osteocytes
Mature bone cells
Osteoclasts
Cells that break down (resorb) bone matrix

15. (c) Osteocyte (d) Osteoclast Mature bone cell that maintains the
bone matrix
Bone-resorbing cell
Figure 6.4c-d

16. Microscopic Anatomy of Bone: Compact Bone
Haversian system, or osteon—structural unit
Lamellae
Weight-bearing
Column-like matrix tubes
Central (Haversian) canal
Contains blood vessels and nerves

17. Artery with capillaries Structures in the Vein central canal
Nerve fiber
Lamellae
Collagen
fibers
run in
different
directions
Twisting
force
Figure 6.6

18. Microscopic Anatomy of Bone: Compact Bone
Perforating (Volkmann’s) canals
At right angles to the central canal
Connects blood vessels and nerves of the periosteum and central canal
Lacunae—small cavities that contain osteocytes
Canaliculi—hairlike canals that connect lacunae to each other and the central canal

19. Compact
bone
Spongy bone
Central
(Haversian) canal
Perforating
(Volkmann’s) canal
Endosteum lining bony canals
and covering trabeculae
Osteon
(Haversian system)
Circumferential
lamellae
(a)
Perforating (Sharpey’s) fibers
Lamellae
Periosteal blood vessel
Periosteum
Nerve
Vein
Artery
Lamellae
Central
canal
Canaliculi
Lacuna (with
osteocyte)
Osteocyte
in a lacuna
Lacunae
Interstitial lamellae
(b)
(c)
Figure 6.7a-c

20. Microscopic Anatomy of Bone: Spongy Bone
Trabeculae
Align along lines of stress
No osteons
Contain irregularly arranged lamellae, osteocytes, and canaliculi
Capillaries in endosteum supply nutrients

21. Nerve Vein Lamellae Artery Central canal Canaliculus Osteocyte Lacunae
in a lacuna
Lacunae
(b)
Figure 6.3b

22. Chemical Composition of Bone: Organic
Osteogenic cells, osteoblasts, osteocytes, osteoclasts
Osteoid—organic bone matrix secreted by osteoblasts
Ground substance (proteoglycans, glycoproteins)
Collagen fibers
Provide tensile strength and flexibility

23. Chemical Composition of Bone: Inorganic
Hydroxyapatites (mineral salts)
65% of bone by mass
Mainly calcium phosphate crystals
Responsible for hardness and resistance to compression