Lecture 4 Flashcards
5 bone shapes, and example of each?
Long - tibia, fibula, Short - trapezium, capitate, Flat - parietal, scapula, Irregular - vertebrae, Sesamoid - patella.
What does periosteum mean?
Outer surface of bone.
What does endosteum mean?
Inner surface of bone.
What does diaphysis mean?
Long, thin middle portion of bone.
What are epiphysis?
Widened ends of bone.
Where is metaphysis?
Between epiphysis and diaphysis.
6 functions of bone?
Support organs, protection, system of levers, store for minerals, haemopoiesis, endocrine organ?
2 components of bone matrix?
Osteocollagen - organic component.
Hydroxy-apatite - mineral component.
6 things forming osteocollagen?
Type I collagen,
bone proteoglycan,
osteocalcin, osteonectin, osteopontin (3 non collagenous proteins).
Hydroxy-apatite.
What is collagen I biochemically speaking?
3 amino acid repeat. Gly-X-Y.
What do osteoblasts do?
Synthesise bone matrix before priming it for subsequent mineralisation.
What shape are they, and what do they contain?
Plump cuboidal.
Many organelles for synthesis and secretion of protein.
Where are they found?
Form epithelioid layer on bone surface.
What are osteocytes formed from, and when?
Formed from oustblasts when engulfed in bone matrix during apposition.
Where are osteocytes found, and what do they rely on to survive?
Entombed within bone matrix.
Rely on canaliculi to bone surface and other entombed cells.
What may osteocytes function in?
May function in regulation of calcium homeostasis and act as strain gauge for physical loads.
What are osteoclasts (structurally), and what is their function?
Large multinucleate cells.
Resorption of bone.
What are lining cells?
Osteoblasts which have completed phase of synthetic activity.
Can lining cells reactivate?
Yes.
2 types of bone matrix?
Woven or dense.
What are osteons/Haversian systems?
Bone units in dense bone.
- Haversian canals,
- Volkmans canals,
- Lacunae,
- Canaliculi.
What are Haversian’s and Volkman’s canals?
Haversian - longitudinal tunnels for blood vessels surrounded by dense osteocytes.
Volkman - Horizontal tunnels for blood vessels.
What are lacunae and canaliculi?
Lacunae - caves in matrix occupied by osteocytes.
Canaliculi - Minute supply pipes between lacunae and canals.
What type of growth does cartilage use?
Interstitial growth.
