Question

Look Out Below: A Case Study on Bone Tissue Structure and Repair An elderly patient arrived at the emergency room unconscious after an accident in which a heavy overhead shelf struck her arm. Upon auscultation, a large open wound on her arm was evident with what appears to be bone tissue sticking out of the skin. She also has bruises covering her left shoulder, left wrist, and lower back. To determine the extent of her injuries the patient undergoes several x-rays, which reveal the following:

5. Most connective tissue, including bone, is highly vascular. Which anatomical structures in the patient’s compact bone house blood vessels?

6. What term is used to describe the addition of new bone tissue? Identify which bone cell is responsible for this process and explain how it occurs.

7. What makes up the organic and inorganic portions of the bone’s extracellular matrix (ECM)? 8. Describe the structure of an osteon.

Discussion:

Further diagnostic tests on the patient revealed a lack of estrogen and calcium. Elaborate on how these factors may have made the injury worse. In normal conditions, what would be the response to falling calcium levels? Post your response and respond to two of your classmates using at least 3-5 sentences to receive full credit (10 points).

Answer 1

Answer 5:

The compact bone has central canal also known as Haversian canal which houses blood vessels. It also houses nerves.

Answer 6:

Addition of new bone tissue is called bone ossification. It is the process of bone remodeling. Bone cells called osteoblasts performs bone ossification process. Osteoblasts secretes matrix which is made up of collagen. After this inorganic salts are deposited in it to harden it. This process radiates outwards from the centre of ossification.

Answer 7:

Organic portion of extracellular matrix consists of Type I collagen fibres and inorganic portion consists of hydroxyapatite and calcium and phosphate salts.

Answer 8:

Osteon is structural unit of compact bone and has following parts:

Lacunae --- It is a small cavity which is present in matrix of bone that contains osteocyte.

Lamellae --- These are the concentric rings of bone matrix which surrounds the Haversian canal.

Canaliculi --- They are the channels between the bones.

Interstitial Lamellae --- The space or bone between the osteons is called as Interstitial Lamellae.

Haversian canal/Central canal --- They are the channels in bone through which blood vessels and nerves passes.

Cement line --- These are the part of bone matrix which are poor in collagen.