Cartilage, Bone, Bone Development, Joints: Answers

Cartilage

#5 Trachea

Why is the territorial matrix more intensely basophilic, and what is its significance?
Glycosaminoglycans > collagen. Note that the region outside the territorial matrix may be less basophilic in places.
What is the most likely reason for this?
More collagen than ground substance.

#6 External Ear (Weigert Elastic Stain)

Where else does elastic cartilage occur in the body?
Nose, epiglottis, larynx, walls of Eustachian tube and external auditory canal.

Questions

  1. What are the mechanisms of cartilage growth?
    Appositional and interstitial growth.
  2. What is the distribution of blood vessels in cartilage, and how does this relate to the nutrition of cartilage?
    Blood vessels in perichondrium only. Nutrition by diffusion through ground substance.

Decalcified Bone

#10 Shaft of Long Bone, Cross Section (H & E)

How does the orientation of the Haversian systems relate to the axis of the shaft of the bone?
Parallel.

#11 Rib, Cross Section. (H & E)

The cementing lines that delimit the Haversian systems may appear refractile or slightly basophilic. What accounts for this basophilia?
Proteoglycans.

How does the orientation of the Haversian systems relate to the axis of the shaft of the bone? Parallel.
Answers

Questions

  1. What is the significance of Volkmann's canals?
    They are a conduit for blood vessels and nerves from the periosteum.
  2. What structures are found within Haversian canals?
    Capillaries and nerves.
  3. Is the osseous lamella adjacent to the Haversian canal the youngest or the oldest lamella of a particular osteon?
    The youngest.
  4. What is responsible for the intense basophilia of osteoblasts?
    Ribosomes.

Joints

  1. What is the composition of synovial fluid?
    Ultrafiltrate from synovial capillaries and mucin produced by synovial cells.
    What are its functions?
    Nutrition and lubrication.
  2. How are most of the cells of the articular cartilages nourished?
    Synovial fluid.

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