Study Question Ten & Eleven & Thirteen

• Q10. How could you differentiate between compact and cancellous (spongy) bone?
• Compact bone is relatively dense and solid
• Spongy bone, or cancellous bone, forms an open network of struts and plates
• In compact bone, the functional unit is the osteon.
• Compact Bone. In an osteon, the osteocytes are arranged in circular layers around a central canal which contains the blood vessels that supply the osteon.
• Compact Bone. Central canals run parallel to the surface of the bone
• Compact Bone. Another passageway is the perforating canals, extend perpendicular to the surface
• Compact Bone. The cylindrical concentric lamellae of each osteon are arranged parallel to the long axis of the bone
• Compact Bone. Interstitial lamellae fill the spaces between the osteons in compact bone
• Compact Bone. Circumferential lamellae occur at the external and internal surfaces of the bone
• Spongy bone, a huge difference from compact bone is the organization, which runs into parallel struts or thick branching trabeculae
• Periosteum is a connective tissue wrapping that is connected to the deep fascia
• From Lab. DRY GROUND COMPACT BONE seen from the microscope:

  • Central Canal, round and circular. The space that holds the blood vessels is also the center of the osteon.
  • Perforating Canals, oval-shaped and longer. The space that holds the blood vessels going across the bone.
  • Lacunae, small holes in the dark space around central canals. Holds osteocytes.
  • Canaliculi, veins or lines branching out from canals to lacunae.
  • Lamellae, bone matrix, the space between. Concentric Lamellae are in the central canal, Interstitial Lamellae are in the space outside the canals.
• From Lab. DRY GROUND COMPACT BONE seen from the microscope:

  • Tissue type? Dry Ground Compact Bone
  • Structure function? The Central Canal is the center of the osteon and space that held blood vessels. The Perforating Canals is space which held blood vessels going across the bone. The Lacunae holds osteocytes. The Canaliculi are tunnels that transport molecules between lacunae. The Lamellae is bone matrix.
  • Specific location? Superficial bone
  • Specific tissue function? Protection and to absorb force in a direction
• From Lab. CANCELLOUS (SPONGY) BONE seen from microscope:

  • Trabeculae, thick branching lines. The basic unit of spongy bone
  • Lacunae, white space around osteocytes located in the trabeculae
  • Marrow, substance and everything outside the trabeculae
  • Osteocytes, dots surrounded by lacunae and inside the trabeculae. Maintain the bone matrix
• From Lab. CANCELLOUS (SPONGY) BONE seen from microscope:

  • Tissue type? Cancellous (Spongy) Bone
  • Structure Function? Trabeculae are the basic unit of spongy bone. Lacunae are space for a bone cell. Marrow produces new blood cells. Osteocytes maintain bone matrix
  • Specific location? At the ends of long bones
  • Specific tissue function? Bone marrow storage, flexibility, and compression
• Q11. What are the similarities and differences in the histology and function of compact vs. cancellous bone?
• In long bones, compact bone predominates in the shaft and surrounds the medullary cavity, while spongy bone is found in the ends and lining the medullary cavity.
• In flat bones, compact bone forms the outer layers with spongy bone in between.
• Q13. Compare and contrast the following aspects of compact and cancellous bone: their structures, their functions, and where each would be located in a long bone and flat bone.