Phase 1a revision - Bone Anatomy & Phsyiology Flashcards
What are osteogenic stem cells?
- Cells derived from mesenchymal stem cells and have the capacity to differentiate into osteoblasts and chondroblasts
What are the 5 types of bone?
- Flat bones
- Long bones
- Irregular bones
- Short bones
- Sesamoid bones
Where does red marrow reside in?
- Cancellous bone
What are osteocytes?
- Osteocytes are mature osteoblasts that have been enveloped within the bone matrix
Where do osteocytes reside?
- Osteocytes reside within the lacuna and communicates with surroundings by canaliculi
What are the main functions of osteocytes (3)?
- Capable of bone deposition and resorption involved in bone deformation caused by muscular activity
- Strengthens bone in response to additional stresses
- Continue to form bone to an extent (maintain strength of the bone matrix)
What is the function of the osteoblasts?
- Responsible for the catalysing and synthesising the mineralisation of osteoid during bone formation and remodelling
Which cells do osteoblasts arise from?
- Arise from the differentiation of osteogenic cells in the periosteum – the tissue that covers the superficial surface of bone and in the endosteum (marrow cavity)
- Differentiation requires constant supply of blood
What is the periosteum?
- The tissue that covers the superficial surface of bone
What do osteoblasts secrete (5)?
- Alkaline phosphatase
- Colleganase
- Growth factors
- Collagen
- Osteocalcin
What are osteoclasts?
- Osteoclasts are large multinucleated cells responsible for the dissolution and absorption of bone – mediators of bone destruction by phagocytosis
Where do osteoclasts reside?
- Within Howship Lacunae - caused by ther erosion of bone by osteoclast derived enzymes
What are the 2 main types of bone?
- Immature woven (primary) bone
- Mature lamellar (secondary) bone
How are the collagen fibres organised within woven bone?
- In a haphazard organisation
What is the first type of bone formed in embryonic development and fracture healing?
- Primary bone - immature woven bone
What are the two forms of mature bone?
- Cortical (compact) bone
- Cancellous (cancellous) bone
Which type of bone ensheathes the bony medulla?
- Cortical bone
How is cortical bone organised?
-
Lamellar configuration
- Densely arranged osteons (Haversian systems)
What is an osteon?
- The chief structural unit of compact (cortical) bone consisting of:
- Contain a central canal that is surrounded by concentric rings (lamella) of the matrix
- Osteocytes located between lamellae within the small cavities - lacunae
- Canaliculi radiate from the launcae to the Haversian canal to provide passageways through the hard matrix