Please help 1. An existing piece of cartilage (e.g. one that forms during fetal
ID: 183182 • Letter: P
Question
Please help
1. An existing piece of cartilage (e.g. one that forms during fetal development) can increase in size “from the inside” and “from the outside.” What term refers to “growth from the inside,” and what term refers to “growth from the outside?” Identify the cells responsible for each kind of growth.
2. “Mature” bone – both compact bone and spongy bone – is described as lamellar bone (i.e., bone
in layers).
How does the ECM of lamellar bone differ from that of woven bone (the first type of bone that forms in
during initial bone formation, during repair of damaged bone, and during bone growth)?
In what form are the lamellae of spongy bone and the lamellae of compact bone?
3. What is a lacuna?
What is found within a lacuna in cartilage, and what is found within a lacuna in bone?
Indicate a fundamental difference between a bone lacuna and a cartilage lacuna – a difference unrelated
to what is found within the lacunae (previous bullet point)
Explanation / Answer
1.
Interstitial Growth - Growth from the "inside"
Appositional Growth - Growth from the "outside"
name of the cell - chondrocytes actively divides and secretes new matrix, expanding cartilage from within.
2.
-ECM of Lamellar is organised but in woven it is disorganised. Lamellar bone replaces woven bone & red marrow appears. It is also called compact bone. The lamellae in compact bone form tubular structures.
- lamellae of spongy bone - Spongy bone contains a mesh-like structure of trabeculae plates, with random orientation.
the lamellae of compact bone - Compact bone contains organized tubular osteons, which are Osteons are organized in the direction of the force.
3.
Lacuna is small cavities that contain osteocytes/chondrocytes.
chondrocytes are found in the lacuna of cartilage, canaliculi and nucleated osteocytes in the lacuna of bone
.
Lacuna of bone Lacuna of cartilage only one osteocyte is present 2 or 4 or group of chondrocytes are present may contain bone marrow Absent impregnated with calcium salt May or may not be present.