Cartilage and Bone Flashcards
What is the common embryonic origin of cartilage and bone?
Mesenchyme
What is the order of cell development which forms bone?
- Mesenchyme
- Osteoblast
- Osteocyte
- Bone
What is the order of cell development which forms cartilage?
- Mesenchyme
- Chondroblast
- Chondrocyte
- Cartilage
Name 4 features of cartilage
- Strong but slightly flexible
- Withstands compression forces
- Major role in endochondral ossification
- Avascular
How do chondroblasts change into chondrocytes?
Chondroblasts secrete ECM and become trapped inside to become chondrocytes
How do chondrocytes exist in the matrix?
Enclosed in lacunae
What are the 3 types of cartilage?
- Hyaline
- Elastic
- Fibrocartilage
Name 3 places hyaline cartilage is found
- Articular surfaces of bone
- Trachea + Bronchus
- Costal cartilage
Name 2 places elastic cartilage is found
- Pinna of external ear
2. Epiglottis
Name 3 places fibrocartilage is found
- Tendon insertions
- Pubic symphysis
- Intervertebral discs
What colour does hyaline cartilage stain in H&E?
Mottled
What comprises the matrix of hyaline cartilage?
Type 2 collagen fibres embedded in a gel of proteoglycans and structural glycoproteins
Why can hyaline cartilage work as such an effective shock absorber?
High water content bound to GAGs
What does GAG stand for?
Glycosaminoglycan
What is the main difference between elastic and hyaline cartilage?
Elastic cartilage contains elastic fibres
What is the main difference between elastic and hyaline cartilage and fibrocartilage?
Fibrocartilage lacks a perichondrium
What is the perichondrium?
A dense irregular connective tissue which surrounds cartilage
What is the main type of collagen contained in fibrocartilage?
Type 1
What is the usual arrangement of chondrocytes in fibrocartilage?
Linear
What 3 things make up the bone matrix?
- Type 1 Collagen
- Proteoglycan aggregates
- Glycoproteins
What adds strength to the bone matrix?
Calcium phosphate in the form of hydroxyapatite crystals
What is the function of osteoclasts?
Resorb bone for regeneration function
What is the function of osteoblast?
Forms the bone matrix
What is the function of osteocytes?
Maintains bone tissue
Where is the exclusive location of osteoblasts?
Surface of bone tissue
What does an osteoblast form from?
Osteoprogenitor cell
What is the principle bone cell of an adult skeleton?
Osteocyte
What connects lacuna in compact bone?
Cytoplasmic extensions in canaliculi
What are the two main differences between osteocytes and chondrocytes?
- Canaliculi connect osteocytes
2. Chondrocytes can appear as clusters
Where are osteoclasts found?
Howships lacunae
What are 2 main features of osteoclasts?
- Highly folded cell surface
2. Multinucleate
What are the two types of bone?
- Compact
2. Spongy
How is compact bone arranged?
Concentric lamellae of collagen fibres around central canal containing vessels or nerves
How can the arrangement of compact bone be referred to?
Osteon / Haversian System
How is spongy bone arranged?
Bone organised into plates of bone called trabeculae
What is the periosteum?
Dense irregular connective tissue covering outer surface of bone
What cells are found in the periosteum?
Osteoprogenitor cells
How does bone bind to periosteum?
Sharpey’s fibres (bundles of collagen) which penetrate bone matrix
What is the endosteum?
Single layer of osteoprogenitor cells and small amount of CT found just inside periosteum
What are the 2 main functions of the endosteum?
- Provide nutrients to bone tissue
2. Provision of new bone cells
