What are the functions of bone tissue?
- Structure/support,
- Attachments - muscles/tendons, ligaments,
- Protection - Vital organs,
- Blood production,
- Storage of minerals - e.g. Ca, phosphates,
- Energy storage - fat in yellow bone marrow,
- Hearing - bones in the skull.
What is the anatomical classification of bones?
- Short,
- Irregular,
- Long,
- Flat,
- Seasmoid.
What are the types of osseous tissue?
- Compact (cortical) bone,
- Spongy (trabecular) bone.
Describe the make up of Compact bone?
- Osteons = concentric rings (lamellae) of calcified matrix surrounding vertically oriented blood vessels,
- Osteocytes in lacunae communictae through canaliculi,
- Interstitial lamellae represent older osteons.
Describe Spongy bone?
- Osteocytes in lacunae on the surface of the trabeculae (little beams),
- Nutrients directly rom the blood in the medullary cavities.
Name the 4 types of bone cells?
- Osteoprogenitor cells - undifferentiated cells,
- Osteoblasts - build matrix & collegen fibres but can’t divide,
- Osteocytes - mature cells,
- Osteoclasts - cells bone cells.
Bones develop in 2 diffrerent ways during embryonic development, what are they?
- Intramembranous Ossification,
- Endochondrial Ossification.
What happens during Intramembranous Ossification?
- Forms flat bones,
- Mesenchymal cells form fibrous membranes,
- Ossification centre develops within membrane,
- Bone matrix secreted,
- Forms spongy bone first,
- Collar of compact bone formed around the periphery second.
What happens during Endochondral Ossification?
- Inital cartilage model formed,
- Bone collar formed,
- Blood vessels penetrate into cartilage,
- Primary centre of ossification develops,
- Spongy bone developed,
- Blood vessels penetrate into epiphyses forming secondary centres of ossification.
The skeletn is a dynamic structure. What is it’s remodelling affected by?
- Age,
- Mechanical stress,
- Genetic & environmental levels,
- Hormone levels,
- Calcium & phosphate levels.
Give an example of a bone disorder that can occur during feotal development?
Agenesis of limb bud, Spina bifida, Osteogenesis imperfecta, Achondroplasia.
What are the bone disorders linked to the aging process?
- Osteopenia,
- Osteoporosis.
Fractures are named according to several factors what are they?
- Severity - Open/compound, closed/simple, impacted, comminuted, displaced, compressed.
- Shape - Spiral, oblique, transverse, depressed.
- Position - distal/proximal 1/3, shaft, neck, epiphyseal.
- Physicians name - Colles, Potts.
What are the stages of fracture healing?
- Haematoma formation,
- Fibrocartilaginous callus formation,
- Bony callus formation,
- Bone remodelling.
Describe what occurs during the first stage of fracture healing?
- Formation of haematoma,
- Clot produced in 6-8 hours,
- Bone cells die,
- Inflammation brings phagocytic cells,
- New capillaries grow into the damaged area.
Describe what occurs during the second stage of fracture healing?
- Fibrocartilagenous callus formation,
- Fibroblasts invade the procallus & lay down collogen,
- Chondroblasts produce firbocartilage.
Describe what occurs during the third stage of fracture healing?
- Formation of bony callus,
- Osteoblasts secrete spongy bone taht joins the broken ends of bone,
- Lasts 3-4months.
Describe what occurs during the fourth stage of fracture healing?
- Bone remodelling,
- Compact bone replaces the spongy in the bony callus,
- Surface is remodelled back to normal shape,
- Sometimes a palpable lump remains.
List 3 factors that can affect fracture healing?
Type of fracture, site of fracture, vascular supply, age of patient, movement at fracture site, separation of bone ends, infection, bone pathology.
Give 3 complications of fractures?
Delayed/mal/non-union, avascular necrosis, sudecks atrophy, compartment syndrome, Volkmanns ischaemia, Myositis Ossificans, blood vessel, nerve or visceral damage, tendon injury, fat embolus, Osteoarthritis, growth impairment.
