Bone 1 Flashcards
Name 4 main functions of Bone:
- A mineral store (in case of malnutrition)
- Protection
- Weight bearing/support
- Blood Formation (red bone marrow)
Explain the structure of Osteon/Haversian systems in compact (cortical) bone:
Organised into circular structures called osteons which surround haversian channels that carry blood vessels (giving the name Osteon/haversian systems).
Explain the structure of Spongy Bone:
A network of lamellated trabeculae (partitions formed by connective tissue) filled with marrow.
The trabeculae are orientated in the direction of the main mechanial forces acting on the bone.
What are 3 other names for spongy bone?
Cancellous, tabecular and diploe bone.
What are Volkmanns channels?
Horizontal Volkmanns channels carry blood vessels and link haversian channels in compact bone.
What are osteons made of?
Osteons are made of osteocytes and concentric sheets of bone matrix (lamellae).
What are the 6 main bone types?
- Flat Bone
- Short Bone (carpal in hand)
- Long bone (femur)
- Sutural Bone
- Irregulalar Bone (Vertebre)
- Sesamoid Bone (Patella)
Name two types of Bone Development?
- Endochondral, the most common type
- Intramembranous, flat bones e.g. flat bones of skull, mandible and clavicle.
What are the 4 steps of endochondral bone development (ossification)?
- A cartilage model of the bone is formed
- Blood vessels invade and vascularize the cartilage
- Bone replaces the cartilage (ossification)
- Cartilage remains in the epithyseal growth plate but eventually ossifies too.
How does intramembranous bone development (ossification) occur?
- Mesenchymal (multipotent stem cells) cells develop into osteoprogenitor cells.
- osteoprogenitor cells mature into osteoblasts and start depositing bone
- Residual mesenchymal cells develop into blood vessels and marrow
What are the 2 main differeneces between endochondral and intramembranous ossification?
- intramembranous involves no cartaligenous phase
- intramembranous can occur in adult cortical (compact) bone
What 3 cell types make up Bone and what are their functions in short?
- Osteoblasts, secretes bone tissue
- Osteocytes, formed when an osteoblast becomes embedded in the bone it secretes. They maintain the bone matrix and sense mechanical forces.
- Osteoclasts, large & multinucleic. It absorbs bone tissue during growth and healing.`
What makes up the ECM of bone tissue?
- the largest part is hydroxyapatite crystals (mineral)
- Type 1 collagen
- a lower than normal amount of water
What is the function of hydroxyapatite in the ECM?
- It makes the bone very stiff and able to support other structures
- It is very strong under compressio
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What is the function of type 1 collagen in the ECM?
- It give the bone flexibility and reduces fracture risk
- its very strong under tension