Bone and Cartilage Flashcards
What are the cells involved in cartilage production?
Chondroblasts
How does cartilage receive oxygen and nutrients?
Long range diffusion
What is the name of the compartments where chondrocytes are found?
Lacunae
What substances do chondroblasts produce?
Fibres and ground substance
What are the three types of cartilage?
Hyaline, Elastic and Fibrocartilage
Where is hyaline cartilage located in the body (4 in total)
Articular surfaces of bone
Trachea and bronchus
Costal cartilages
Nasal cavity and nose
Where is elastic cartilage located in the body (2 in total)
Pinna of external ear
Epiglottis
Where is fibrocartilage located in the body (4 in total)
Tendon insertions
Pubic symphysis
Intervertebral discs
Articular menisci (knee joint)
What is the name of the CT capsule surrounding cartilage (absent in fibrocartilage)
Perichondrium - Dense regular connective tissue
What is the main function of hyaline cartilage?
Shock absorption
What are the main components of hyaline cartilage?
Collagen type II fibres embedded in a firm hydrated gel of proteoglycans and structural glycoproteins
What are the main fibrous components of elastic cartilage?
Collagen type II and elastic fibres
What is the structure of fibrocartilage?
Chondrocytes arranged in straight rows separated by collagen type I fibres
What is the main function of fibrocartilage?
Combines tensile strength with shock absorption: Resists compression
What are the main functions of bone (6 in total)
- Protects internal organs
- Stores and releases fat
- Produces blood cells
- Stores and releases nutrients
- Facilitates movement
- Supports body
What comprises the bone matrix?
- Collagen type I (95% of organic matrix)
2. Proteoglycan aggregates and specific glycoproteins (5% of organic matrix)
What form is calcium bound to the bone matrix?
Calcium phosphate in the form of hydroxyapatite crystals
Involved in the mineralisation of bone
What are the three bone cells?
- Osteoblasts
- Osteocytes
- Osteoclasts
What is the main function of osteoblasts?
Forms the bone matrix
What is the main function of osteocytes?
Maintains the bone matrix
What is the main function of osteoclasts?
Resorb bone
Where are active osteoblasts required for?
Required before the osteoid material can be deposited
Osteoid is the unmineralised component of the bone
What is the unmineralised component of bone?
Osteoid
Where are osteoblasts located?
On the surfaces of bone tissue
What is the progenitor cell of osteoblasts/osteocytes?
osteoprogenitor cell
What is the name of the small channels that connect lacunae in bone?
Canaliculi
What is the function of canaliculi?
Permit the flow of nutrients and oxygen through the bone matrix
Where are osteocytes located?
In lacunae within the mineralised matrix
How do osteoclasts resorb bone material?
They release enzymes such as collagenase and by dissolving calcium salt crystals
From what cells are osteoclasts derived?
Monocyte phagocyte lineage
Where are osteoclasts located?
Sit on the bone surface in depressions known as HOWSHIP’S LACUNAE
What is a distinct feature of osteoclasts?
The cell surface in contact with bone is highly folded, forming a RUFFLED BORDER (increases the surface area for maximum bone resorption)
What are the two types of bone?
Compact bone and spongy bone
Give another name for compact bone
Cortical bone
Give two other names for spongy bone
Trabecular or cancellous bone
Describe the structure of compact bone
Dense areas without cavities
Collagen fibres are organised in concentric lamellae around a canal containing blood vessels and nerves. These are known as Osteons or a Haversian system
Give two names for a unit (circle thing) in compact bone
Osteon
Haversian system
What is in the centre of a Haversian system?
Haversian canal
What passes though the Haversian canal in compact bone?
Blood vessels and nerve
Describe the structure of spongy bone
Areas with numerous interconnecting cavities
Absent of osteons
How is spongy bone organised?
Spongy bone is organised into plates of bone called trabeculae/spicules. The Lamella within the trabeculae are arranges concentrically with no central canal
What is the connective tissue layer that surrounds bone
Periosteum
What is the periosteum comprised of?
Dense irregular connective tissue and osteoprogenitor cells
What connects the periosteum to the underlying bone matrix?
Sharpey’s fibres (bundles of collagen fibres)
What is the endosteum comprised of?
A single layer os osteoprogenitor cells and a very small amount of connective tissue
What is the function of the periosteum and the endosteum?
To provide nutrients to the bone tissue and provision of new bone cells.
