Please enable JavaScript.
Coggle requires JavaScript to display documents.
SKELETAL SYSTEM - Coggle Diagram
SKELETAL SYSTEM
GROWTH & REPAIR
APPOSITIONAL BONE GROWTH
-
-
-
Osteoblast role
- Secrete matrix on external bone under periosteum
Osteoclast role
- Remove bone on endosteal surface
-
Thicker, stronger bone without excess weight
INTERSTITIAL BONE GROWTH
Requires presence of epiphyseal cartilage
- Epiphyseal plate maintains constant thickness
Cartilage growth on one side
- Blanaced by bone replacement on other
Chondrocytes rapidly divide
- Pushes epiphysis away from diaphysis (lengthening)
-
-
-
BONE FRACTURES
Position of bone ends after fracture
- Non-displaced - ends retain normal position
- Displaced - ends out of normal alignment
Completeness of break
- Complete - broken all the way through
- Incomplete - not broken all the way through
Whether skin is penetrated
- Open (compound) - skin is penetrated
- Closed (simple) - skin is not penetrated
-
BONE REPAIR
4 stages of bone repair & remodelling1. Haematoma Formation
- Torn vessels, clotting, phagocytes clear debris
2. Fibrocartilaginous Callus
- Collagen secreted, broken ends joined, spongy bone
3. Bony Callus
- Trabecular appear in callus, compact bone forms
4. Bone Remodelling
- Excess materials removed, shaft walls reconstructed
JOINTS & ARTICULATIONS
JOINT CLASSIFICATION
Joints are classified functionally:
- Syntharthroses - Immovable joints
- Amphiarthroses - Slightly moveable joints
- Diarthroses - Freely moveable joints
Joints are classified structurally:
- Firous - Immoveable or slightly moveable
e.g. Skull sutures, Periodontal liagements
- Cartilaginous - Immoveable & immobile
e.g. RIb & sternum joints, Intervertbral discs
- Synovial - Highly moveable with fluid
e.g. Majority of joints; Patella, shoulder
SYNOVIAL JOINT FEATURES
Articular (Hyaline) cartilage
- prevents crushing of bone ends
Joint (Synovial) cavity
- small, fluid filled space
Articular (Joint) capsule
- external fibrous layer - dense irregular CT
- inner synovial membrane - makes synovial fluid
Synovial fluid
- viscous; lubricates & associated structures
Reinforcing ligaments
- stabilise the joint & associated structures
Nerves & blood vessels
- pain, position, stretch, filtrate for synovial fluid
BONE COMPOSITION
BONE FUNCTION
Bones contribute to body shape, body form and:Support
- Hard framework that supports & cradles soft organs
Protection
- Protective casing for soft organs against external forces
Movement
- Muscles use bones as anchors & levers for movement
Mineral Storage
- Mineral 'reservoir' (Ca+, K+) for deposit & withdrawal
Blood Cell Forametion
- Blood cell formation occurs within marrow cavities
SKELETAL CLASSIFICATION
-
Grouped according to:The Axial Skeleton (80 bones)
- Forms the long axis (trunk) of the body
- Function: protection, support, carrying body parts
- Skull, vertebral column, rib cage
The Appendicular Skeleton (126 bones)
- Forms the appendages of the body
- Function: locomotion, environmental manipulation
- Upper & lower limbs, shoulders, hips
Also classified according to size & shape
BONE CLASSIFICATION
Long bones
- Consists of an elongaed long shaft & 2 ends
e.g. fingers, femur
Short bones
- generally cube-shaped & stubby
e.g.wrist, ankles, patella (sesamoid)
Flat bones
- Thin, flattened & slightly curved
e.g. skull, ribs, sternum, shoulder blades
Irregular bones
- Complicated shapes not fitting any classes
e.g. vertebrae, pelvis
SKELETAL CARTILAGE
-
-
Hyaline cartilage (collagen)
- Support, flexibility & resilience
- Ribs & joint surfaces
Elastic cartilage (elastin)
- External ear & epiglottis
Fibrocartilage (thick collagen)
- Great tensile strength
- Menisci of knee; vertebral discs
BONE STRUCTURE
BONE MACROSTRUCTURE
Most long bones consist of:Diaphysis (shaft or long axis)
- Thick external collar of compact bone
- Central medullary cavity of bone marrow
Epiphyses (ends)
- xpanded end of the long bone shaft
- Consists mainly of spongy bone
Periosteum (membranes)
- Dual-layer covers entire external bone surface
- Supplied with nerve, lymphatic & blood vessels
BONE MICROSTRUCTURE
Bone consists of 2 layers:Compact bone (hard)
- Osteon (haversian system) - Mineralised, structural unit
- Haversian Canal (Contains capillary & nerve supply
- Volkmann's Canal - Link blood & nerves to periosteum
Spongy bone (Cancellous)
- Trabeculae - Align along stress lines
- Lamelae - Deposited by osteocytes in rings
- Canaliculi - Canals joining lamellae & osteocytes
- Endosteum - Surrounds trabecular providing nutrition
BONE COMPOSITION
Bone has a solid matrix composed of:
- Osteoid - Organic;collagen, flexibility
- Mineral salts - Inorganic; Ca3 (PO402; durability
Matrix is maintained by specific cells:
- Osteocytes - mature bone cells; former osteoblasts
- Osteoblasts - bone 'forming' cells; add matrix
- Osteoclasts - bone 'degrading' cells; remove matrix
Controlled & regulated by:
- *Parathyroid Hormone (PTH)
- Blood Ca2+ levels decrease; bone matrix degraded; Ca+ released
Calictonin
- Blood Ca2+ leves incerease; Ca2+ deposited in bones; Ca2+ absorbed