Connective tissue (Bones + Joints) Flashcards
What are the different stages in bone development?
- Cartilage models precede the bone
- Cartilage invaded by blood vessels
- Primary ossification begins at centre of shaft
- Secondary ossification centres present at ends of the bone
- Ossification centres meet at epiphyseal plates
- Growth happens as these plates, fuse at end of growth (the primary and secondary ossification centres will fuse with each other)
What are the 4 functions of bones?
- Rigid frame
1. Protection
2. Mineral stores (calcium can be released into the bloodstream in instances where it is deficient in the body)
3. Blood cell generation (haematopetic function)
4. Sound conduction (Vibrations from the ear drum into the inner ear can be transmitted through the stapes)
What makes up bone tissue?
> Matrix: Collagen and Calcium phosphate.
- Collagen fibres : TYPE 1, increase tensile strength + reduce brittleness
- Hydroxyapatite – a form of calcium phosphate Ca10(PO4)6(OH)2 crystals increase stiffness and compressive strength
What are the three types of cells within bone tissue?
What are the three types of cells within bone tissue?
How does Bone remodelling occur?
- Osteoclasts erode bone, tunnelling a canal
- Osteoblasts secrete and mineralise osteoid, forming new bone
- Osteocytes maintain bone
What is the general structure of a bone as an organ?
- 2 parts: Compact/Cortical bone + Cancellous bone
-Bone marrow
-Blood vessels > running through and outside
-Periosteum > innervation
-Articular cartilage
Describe the structure of Cortical bone.
- Dense, solid bone tissue > Generally at margins and diaphyses
- Initially bone develops in circumferential lamellae
- These are overlaid by progressive layers of osteons during remodelling
Describe the structure of Cancellous bone.
- Interconnected mesh of bony struts and plates
- Approximately one osteon wide
- Generally present at epiphyses and intracortical space
- Space filled with marrow
Describe the structure and function of bone marrow.
- Important throughout life in haematopoesis
- Increases lipid content through life
How does bone healing occur?
- Initial fracture - blood vessels rupture
- Bleeding and inflammation - blood clot initiates inflammatory response immune cells move to site + clears necrotic tissue
- Granulation - ECM production + Active proliferation of osteodprogenitor cells
- Soft callus - fibroblast produce collagen = initial stability
- Hard callus - Osteoblasts deposit calcium and phosphorus on the collagen matrix of soft callus weeks to months after.
- Remodelling - Osteoclasts remove excess bone/ Osteoblasts deposit new bone several months after
> No scar formed
What are some interventions used to support bone and encourage its natural healing?
What processes occur as bones age?
Loss of mineral content
Reduced stiffness
Reduced bone density
Loss of bone volume
How are joints classified?
- By tissue type
◦ Fibrous - bones connected by ligaments
◦ Cartilaginous - joints surrounded by hyaline cartilage
◦ Synovial - Joint capsule - By function
◦ Immoveable
◦ Slightly moveable
◦ Moveable
