15) Cartilage and Bone Flashcards
Name the 3 types of cartilage
Hyaline cartilage
Elasic cartilage
Fibrocartilage
What type of cells are present in hyaline cartilage?
Chondrocytes
How does hyaline cartilage develope?
Endochondral ossification
What is the role of chondrocytes?
To produce and maintain the extracellular matrix
What is the function of hyaluronic acid in cartilage?
Provides resillience when pressure is applied by attracting water
What is the structure of ground substance?
Lots of collagen fibres
Lots of proteoglycans attached to the side of hyalauronic acid
Where is hyaline cartilage present?
Between all joints
How does hyaline cartilage form?
In the perichondrium, precursor cells develop into chondropblasts.
Chondroblasts enlarge and undergo appositional or interstitial growth through the extracellular matrix, forming chondrocytes
What is appositional growth?
Growth from the periphery
What is interstitial growth?
Growth towards the centre as growth is occuring in the perichondrium on both sides
Where does Rheumatic Artheritis occur?
On articular surfaces, as damage to the cartilage here cannot be repaired as chondrocytes in adults dont proliferate. Nearby fibroblasts lay down scar tissue which becomes calcified, causing a loss of flexibility in the joint
What is elastic cartilage made up of?
Chondrocytes
Elastic fibres
Where is elastic cartilage found?
Pinna of the ear
Eustacian tube
epiglotis
How does elastic cartilage function?
Lays down fibroelastic cartilage by bursting and releasing its material into the extracellular matrix
What cells are found in fibrocartilage?
Chondrocytes
Fibroblasts
(mix of dense connective tissue and hyaline cartilage)
Where is fibrocartilage found?
Meniscus of knee
cartilage in intervertabral disc
pubic symphysis
What is the function of fibrocartilage?
Shoch absorber
Insulator
Compressable activity
What is the process of bone formation called?
Endochondrial ossification
Describe the process of endochondrial ossification
1) Hyaline cartilage acts as a model template
2) Cortical bone fors on the edges of the shaft
3) The cartilage is calcified and a nutrient artery penetrates the cartilage generating SPICULES, upon which cancellous bone will be laid.
4) The nutrient artery supplies osteogenic cells, forming the primary ossification centre.
5) Post natally cancellous bone is laid and the cartilage forms epiphyseal growth plates
6) Epiphyses developes secondary ossification centres and ossify
7) Growth plates continue to grow and the bone lengthens
8) In adults the grow plates are replaced by bone and hyaline cartilage which works as articular cartilage perists on the edges of the epiphyses.
Describe the structure of bone using a femur as an example
ends=cortical bone, epiphysis enclosed by growth plates, as bone narrows there is the metaphysis
middle= cancellous bone, diaphysis
Where are osteoprogenitor cells found?
endosteum
periosteum
What is the function of osteoprogenitor cells?
To form osteoblasts
What are the functions of osteoblasts?
To lay down new bone and matrix
Forms osteocytes
What is the function of osteocytes?
Bone maintenance
What is the function of osteoclasts?
Bone remodelling to build stronger bone
What is the functional unit of compact bone?
Osteon
Describe the structure of compact bone
Haversian cannal in the centre of osteons
Osteon surrounded layers of bone and osteocytes
Volkmann’s cannal connects Haversian cannals
What is osteoartheritis?
An (age related) degeneration of the articular cartilage causing a mechanical failure and bones to rub against each other as the joint space is narrowed
What is rheumatoid arteritis?
An autoimmune disease cauing inflammation to the synovial membrane, causing bone and cartilage damage
