Skeletal system, bone structure and synovial joint Flashcards
Whats special about the hyoid bone?
- The only bone of 206 that doesn’t articulate (form a joint)
- Forms foundation for voice box and anchor for tongue so is an irregular bone
What is hyaline cartilage?
NOT only bones in skeleton! (Cartilage which is a connective tissue)
- Hyaline found in synovial joints with no perichondrium so it’s very smooth
- Helping freely moveable joints
- Covering end of bones, connecting ribs to sternum, supporting nose in respiratory system
- Providing support and flexibility
What is fibrocartilage?
- Very strong cartilage in skeleton which is compressible
- Role in shock absorption
- E.g., Knees and spine discs between vertebrae and pubis
What are the two divisons of the skeleton?
- Axial – skull and vertebrae column, ribcage and cocksicks – provides central axis and protects most of major organs
- Appendicular skeleton – hanging off axis – pelvic Gerda (lower limbs) and pectoral Gerda (upper)
state main functions of the skeletal system
- Support – body and soft organs
- Protection – brain, spinal cord, vital organs
- Movement – attachment points and levers for muscle action – greater trecento and lessor trochanter – hip joints
- Improving the activity of muscles, tendons and ligaments
- Mineral storage – calcium in the blood for function of brain and found in interstitial liquid
- Hormone storage – growth factors, when broken down by oastioplasts the growth factors are released causing bones to be repaired
- Blood cell formation – haematopoiesis – every 2 hours 8 billion new blood cells created – in bone marrow
- Triglyceride (fat) storage in bone cavities - diathesis (main shaft of the bone) - in yellow bone marrow
- Hormone production – osteocalcin – regulating formation of bones
what are the 5 classifications of bones?
- Long – longer than wide
- Short – wide as they are long
- Irregular – specific and cannot be classified in other groups
- Flat – skull, sternum, flatter
- Sesamoid – embedded in tendon (patella, pisiform (in hand)) - looks like sesame seeds – useful for insertion of tendons
whats a trabeculae?
Between the discs where red bone marrow is found, and blood is made
What is the periosteum?
- membrane covering bones
- sharpey fibres create strong connection between this and the bone as runs in and between – has a very high blood supply - 2 layers
- Fibrous (outer layer)
- Osteogenic (inner) – contains osteogenic cells
What is the endosteum?
- Single layer of cells lining the internal surface of compact bone and cannels
- contains osteogenic cells
- provides nutrients and supports nutrients getting into the bone to be supplied around the bone structure
Name key components of bone cells
- Osteoblast
- Osteoclast
- Osteocyte
- Bone lining cells
What is an osteoblast?
building bone cells – laying down the bone matrix and calcium binding proteins
What is an osteoclast?
- chomper bone cell
- for remodeling
- multinucleate
- a lot larger
- attach to surface of bone due to ruffling structure
- producing enzymes (proteinaceous enzymes) to break down the bone (repaired on the balance between osteoblasts and osteoclast)
What is an osteocyte?
- sitting in a lacuna of the structure of the bone (90% of cells)
- living 25-30 years
- when they die - release signals to stop osteoclasts - more clumps of bones removed
- in old age making bones more brittle osteoporosis)
What is a bone lining cell?
- squamous cells layer
- communicate with osteocytes and is part of the endosteum
- involved in maintaining a source of osteoclasts and osteoblasts
- regulate structure of the bones – but not fully understood
Explain main structure of compact bone (microscopic structure)
- osteons - consentric sylinders of bones set against longitudical axis
- **Haversian canel **– containing blood vessels vertically and volkmanns canels intersept these as they are transverse
- Osteocytes
- cells connected by dendrites – cellular extensions
- canaliculi - making contact so can pass nutrients between oestocytes
