Answers, BIO 2310, Skeletal Tissue

B. SKELETAL TISSUE

1. Not vascular, chondrocytes for cells, intercellular matrix comprised of fibers and ground substance (mucopolysaccharide).

2. Hyaline cartilage is very glossy and the most common type of cartilage. The cells are numerous in their lacunae and the collagen fibers are evenly spaced for the smooth look. It can be found at the tip of your nose and capping bones at synovial joints. Fibrocartilage has strong bundles of collagen fibers making it rough looking and very strong. Fibrocartilage can be found at the pubic symphsis and in intervertebral discs. Elastic cartilage, such as in your outer ear has elastic, stretchy fibers.

3. Minerals (hydroxyapatite crystals – primarily calcium based for hardness), collagen fibers for strength and bone cells in their lacunae.

4. Osteocyte is a mature bone cell. Osteoblast is a bone forming cell and is abundant on the periosteum. Osteoclast is a bone destroying cell and is abundant at the endosteum.

5. Articular cartilage, epiphysis (ends), metaphysis (neck), diaphysis (shaft), marrow cavity, periosteum (outer covering), endosteum (lining marrow cavity).

6. Compact bone has little interosseous space and is characterized by long cylinders called osteons. Osteons have central (Haversian) canals filled with blood vessels as well as perforating canals connecting to the central canals. It has osteocytes and the matrix is arranged in concentric circles called lamellae, which resemble tree rings in cross section. The kind of bone with a lot of interosseous space is spongy or cancellous bone. This bone has little spicules (trabeculae) of bone with space available for red bone marrow and blood cell production.

7. Endochondral ossification occurs with cartilage forming first, followed by the cartilage turning to bone. Intramembranous or direct ossification occurs by the osteoblasts directly making the bone with no cartilage intermediate.

8. Osteoblasts on the periosteum make more bone while the osteoclasts on the endosteum enlarge the marrow cavity.

9. Long – femur; Short – carpal; Irregular – vertebra, Flat – sternum. A miscellaneous category is the sesamoid bone embedded in a tendon. The largest sesamoid bone is the patella.

10. Fissure is a slit-like opening; facet is a flat articular surface such as those on the vertebrae, foramen is a hole for nerves or blood vessels, meatus is a canal, a fossa is a depression, a condyle is a smooth, usually rounded articular surface.

11. 206

12. Axial – 80; Appendicular – 126

13. Support, movement, protection, blood cell production, mineral storage