Bone Flashcards
What makes up a long bone?
- Diaphysis
- 2 epiphysis
- 2 metaphysis
- articular cartilage
- periosteum
- medullary cavity
- endosteum
What is the diaphysis?
- bone shaft
- centre of long bone
What is an epiphysis?
- end of the long bone
- connects to joints
What is a metaphysis?
- part of long bone connecting diaphysis and epiphysis
What does articular cartilage do?
- covers the epiphysis
What is the periosteum?
connective tissue covering the diaphysis
What is the medullary cavity?
Hollow region within the diaphysis
What is the endosteum?
- membrane lining medullary cavity
What is the bone tissue?
- specialised connective tissue
- highly vascular
- constantly changing in response to forces applied
What is the structure of the ECM for bone tissue?
- ECM surrounding widely separated cells
- ECM made of water, organic, and inorganic mineralised materials
What is the function of organic and inorganic materials within bone tissue?
provide rigidity whilst retaining flexibility
What causes bone tissue to be mineralised?
Calcium salts
What are the 4 types of bone cells?
- Osteoprogenitor
- Osteoblasts
- Osteocytes
- Osteoclasts
What are osteoprogenitor cells?
Stem cells
What are osteoblast cells?
Bone-building cells that secrete ECM
What are osteocyte cells?
mature bone cells
What are osteoclast cells?
They remodel bones and release calcium
What are the 2 types of structures bones can have?
- Compact (cortical)
- Spongy (cancellous)
What is the structure of compact bone?
- Dense rigid outer shell of long bone
- Concentric layers around vessels
- Neurovascular chanells with interconnection
- Bone cells are within cavities
- Channels connect bone cells and blood
What is a lamellae?
Concentric layers of bone tissue
What are haversian canals?
Nerovascular channels in bone tissue
What are Volkmanns canals?
Connect haversian canals
What are lacunae?
Bone cells within cavities
What is the structure of spongy bone?
- thin interconnecting bone trabeculae
- lightweight and aligned
- provides structural and tissue support
- Space for red bone marrow and hemopoiesis
What does trabeculae mean?
Honeycomb
What occurs at hemopoiesis?
RBC production
What are the 5 shapes we classify bone via?
- Long
- short
- flat
- irregular
- sesamoid
How is blood supplied to bones?
- periosteal arteries (+veins) enter volkmanns canals
How are nutrients supplied to bones?
- entre centre of diaphysis through nutrient foramen
What is ossification?
bone formation
What are the 2 methods of ossification?
- Intemembranous
- Endochondral
What is intramembranous ossification?
Skull bone formation
What is endochondral ossification?
Long bone formation
What are the 4 situations where bone ossification occurs?
- Embyological and fetal development
- Growth before adulthood
- Remodelling
- Healing fractures
Where does intramembranous ossification occur?
- Within embryonic tissue
What are the 4 steps of intramembranous ossification?
- Ossification centre forms: osteoblast excrete ECM
- Calcification: salts deposited, matrix hardens, osteocytes in lacuna
- Trabeculae form: ECM develops into trabeculae, which become spongy bone
- Periosteum forms
What are the 6 steps of endochondral ossification?
- Chloroplasts form cartilage model
- Chondrocytes undergo cell division, growing cartilage model
- Primary ossification centre forms, cartilage replaced by bone
- Medullary cavity forms via osteoclasts breaking down bone
- Secondary ossification centre forms in epiphysis
- Articular cartilage and epiphyseal growth plate form
How do bones become longer?
Bone material added on diaphyseal side of epiphyseal growth plate via interstitial growth
What happens to the epiphyseal plates during growth?
They undergo endochondral ossification
When does bone stop growing?
When the epiphysis closes
How do bones become thicker?
appositional growth
How does appositional growth occur?
- perosteal ridges close around periosteal blood vessels
- endosteum form
- osteoblasts head towards endosteum, forming concentric circle
What happens to the medullary cavity during appositional growth?
- Osteoclasts destroy bone on inner surface, widening medullary cavity
What are the 3 stages of healing for a fractured bone?
- Reactive: inflamation and bleeding
- Reparative: first a soft callus, then becomes bony callus
- Remodelling: bony callus reshaped
What is an open fracture?
Broken end sticks out of the skin
What is a comminuted fracture?
splintered at impact site
fragments scattered
What is a greenstick fracture?
Occur in kids: not fully ossified
One side broken, one side bent
What is an impacted fracture?
One end of fractured bone forced into another
What is a pott fracture?
Ocurs at lateral end of fibia
What is a colles fracture?
Occurs at lateral end of radius
Name 4 common fractures
- open
- closed
- comminuted
- greenstick
- impacted
- pott
- colles
What is achondroplasia?
- Epiphyseal plate closes before normal bone length is reached
- Short limbs, unaffected trunk and membranous bones
