Mature Bone

Atlas

Ch 10, pgs. 172-175 (Cartilage)
Text

Ross and Pawlina Chapter 8 Bone

Objective

  1. Be able to use standard nomenclature to describe the microscopic structure of bone (e.g. lamella, osteon, osteocytes, canaliculi, periosteum, endosteum).
  2. Be able to recognize mature bone (dense and cancellous) in conventional or ground section. Be able to identify the component parts of mature bone (e.g. osteon, lamella, lacuna, osteocyte) in appropriate sections.
  3. Be able to describe the anatomical route that nutrients and metabolic products use between the vascular system and osteocyte.

MATURE BONE

Slide 50 (fibula, monkey, decalcified, H&E) WebScope ImageScope

Prior to sectioning and staining, this sample was soaked in a weak acid solution thus dissolving the mineralized component of the bone matrix but leaving behind all of the organic components (mostly type I collagen). Even though this section is distorted, you should be able to find osteons in various stages of development, lacunae, and canaliculi (to see canaliculi you will need to use your microscope and the glass slide from your collection –cut down the light by closing down the iris diaphragm to see them). The inner and outer circumferential lamellae #050   Webscope   ImageScope can the bone shaft can also be seen in this section. What distinguishes between compact and spongy bone?  answerThough it is easy to differentiate between compact and spongy bone at a gross level, at the microscopic level the main difference is the presence or absence of osteons. Grossly, compact bone has a dense appearance and is found, for example, on the outer surfaces of the long bones of the body. As the name implies, spongy bone is shaped like a sponge. The spaces within the sponge-shaped framework are filled with bone marrow. Compact bone, microscopically, is made of numerous osteons, whereas spongy bone is composed of sheets of lamellar bone and does not contain osteons.   

Ground sections:
Cross sections:

051 Bone ground section of compact cross Webscope Imagescope
o51XC bone fibula cross Webscope Imagescope
093B Bone ground section of compact bone H&E cross Webscope  Imagescope

Longitudinal sections:

093A Bone Ground section of compact longitudinal Webscope Imagescope
051 Bone Ground section of compact longitudinal Webscope Imagescope
051L-EX Bone Ground section of compact longitudinal Webscope Imagescope
093C Bone Ground section of compact bon longitudinal Webscope  Imagescope

These “ground sections” were prepared by taking pieces of bone and grinding them with abrasives between two glass plates until they are thin enough to be semi-transparent. First, study cross sections (#51, #93B). In these sections, the trapped air bends the light giving a dark image; the mineral and matrix generally transmit the light. You should be able to identify osteons and their subdivisions (as in slide 50), interstitial lamellae, Haversian canals and nutrient canals (Volkmann). Note that the latter canals penetrate osteons without causing new lamellae to be laid down around them. Note that Slide 51xc is also an entire cross section of the fibula, so you should try to compare it against Slide 50 discussed above.

Study the thinnest ground section (#93A) to identify lacunae and canaliculi. (W pg 193, 10.10a). Now, look at the longitudinal sections (#51-20x, #51-40x, or #93C) of compact bone and try identifying the various structures mentioned above, especially Haversian and Volkmann’s canals.