Bone and Cartilage Flashcards
What are the two types of macroscopic bone?
Cortical: Dense. Found at edges of bones. Outer plate.
Cancellous: Spongy
What is the cortical bone lining tooth sockets penetrated by?
Sharpeys fibres.
In the organic mass of bone, what are glycoproteins important for?
Bone regeneration
What fibres are found in the extracellular matrix of bone?
Collages
Elastin
Name the 2 types of microscopic bone.
Woven: Rapid laying Irregular Fracture repair Lots of osteocytes present.
Lamellar:
Slow laying
Parallel collagen fibres
Less osteocytes than woven bone.
Comment on the arrangemnt of compact bone structure.
Concentric lamellae formed in longitudinal columns.
Filled with Haversian systems/canals and volkmann’s canals (LATERAL)
What is the function of Volkmann’s canals?
Links Haversian canals
What is an osteon?
Lamellae surrounding a haversian canal.
What is a Haversian system?
Functionl unit of compact bone.
What is a Haversian canal?
A canal containing blood vessels, nerves and lymphatics.
List the characteristics of cancellous bone.
No obvious Haversian systems.
Bone is thin = nutrients can diffuse.
Bone marrow present in the spaces between trabeculae.
What is osteoblast?
Synthesise and secrete collagen fibres = matrix.
Where are osteoblasts found?
Lie on the surface of bone.
Where are osteoblasts derived from?
mesenchymal stem cells.
What are osteocytes?
An osteoblast that gets trapped in mineralised bone.
Where are osteocytes found?
Lie within the lacunae (spaces)
What are osteocytes able to do via their cytoplasmic processes that run in canaliculi?
Communicate with other osteocytes.
Can also communicate with osteoblasts.
What are osteoclasts?
Cells that resorb bone via acid phosphatases.
Where are osteoclasts derived from?
Haemopoietic stem cells
Define bone remodelling.
Removal and replacement of bone tissue without change in the overall shape.
What cell controls bone remodelling?
Osteoblasts
What is bone remodelling regulated by?
Hormones: Parathyroid and calcitonin.
Paracrines: Cytokines.
What is the advantage of bone remodellin?
Maintains a level of calcium within the body.
In bone remodelling, what is a reversal line?
Scalloped edge that shows where bone resorption changes to bone deposition.
When does tooth movement occur?
Eruption
Post eruptive i.e. drifting
Ortho treatment
Cartilage is…?
Connective tissue
Name the 3 types of cartilage
Hyaline cartilage
Fibrocartilage
Elastic cartilage
What cells produce cartilage?
Chondroblasts.
What are chondrocytes?
Chondroblasts after they become trapped in the matrix.
Name the 2 types of bone growth.
Endochondral
Intramembranous
What is endochondral ossification?
Growth in long bones that includes cartilage being replaced with bone.
What is intramembranous ossification?
Growth of flat bones, no cartilage (precursor)
Where does cartilage proliferation occur in endochondral ossification?
At the epiphyses plates.
What is achondroplasia?
Genetic defect in cartilage growth. ENDROCHONDRAL bone impaired.
(Sphenoid bone at base of skull is unable to grow, yet Intramembranous bones creating the cranium can grow.)
