Date gui: Case Study writing Assignment #1 Within days after a fracture, a \"sof

Question

Date gui: Case Study writing Assignment #1 Within days after a fracture, a "soft callus" of fibrocartilage forms. What fibers are found in this type of cartilage? Identify the cells required for fibrocartilaginous callus formation and list their functions 7. As a fracture is repaired, new bone is added to the injury site. 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. of bone repair, some of the osseous tissue must be broken down and removed What term is used to define the breaking down of osseous tissue? Which bone cell would be best suited for this task? 9. The extracellular matrix (ECM) of bone is considered to be a composite material made up of organic and inorganic matter. What makes up the organic and inorganic portions of the matrix? Describe the cellular mechanism involved in breaking down this matrix; include the bone cell required for the process.

Explanation / Answer

6.Formation of soft callus occurs at the end of first week mainly.,this procallus provides anchorage between the ends of fractured bones.Type 1 collagen fibres are found in this type of callus,after two weeks it gets transformed into bony callus.

Cells required for soft callus formation are-

A).inflammatory cells and degranulated platelets= they release PDGF,TGF-b,FGF, They activate osteoprogenitor cells and stimulate osteoblastic and osteoclastic activity.

B).Osteoblasts,osteocytes = they are bone forming cells.

(Osteoclasts=bone resorbing).

7.The process of addition of new bone tissues is known as osteogenesis or bone deposits.osteoblasts are responsible for it.They synthesize bone matrix.

8.The process of breaking down of osseous tissue is called bonw resorption.This job is done by osteoclasts.They attach to bone matrix(by means of integrins) and create a resorption pit.secretion of acid and neutral proteases (MMPs) into the pit results into dissolution of bone.(basic mechanism)E

9.Extracellular matrix of bone is composed of both organic and inorganic(mineral) components.The organic component is called osteoid and constitutes about 35% of ECM whereas mineral component constitutes about 65%.

Osteoid is made up of -

a). Type 1 collagen (predominant)

b).glycosaminoglycans.

c). Proteins eg-

-calcium binding proteins(osteonectin,bone sialoprotein).

-cell adhesion proteins(osteopontin,fibronectin,thrombospondin).

-cytokines(IL-1, IL-6,RANKL) and growth factors(IGF-1,PDGF)

-Enzymes(collagenase,alkaline phosphatase)

-proteins involved in mineralization(osteocalcin).

-proteins concentrated from serum(albumin,microglobulin).

Inorganic moiety is made up of-

a).hydroxyapatite- [Ca10(PO4)6(OH)2] (it serves as reservoir of calcium and phosphorus).

Related Questions

Navigate

• Browse (All)
• Browse D
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.