Bone And Cartillage Flashcards
Describe Cartillage
Mature type of connective tissue
- has cells (chondroblasts) which produce and (chondrocytes) which maintain the extracellular matrix
- Solid and firm but somewhat pliable
- Outer surface covered by a connective tissue layer called perichondrium
- Avascular- relies of diffusion for most of its nutrients and exchange of gases
What are the types of cartilage?
- Hyaline cartilage
- Fibrocartilage
- Elastic cartilage
What are the functions of cartilage?
- Plays a major role in fetal development of the skeleton
- Provides the epiphyseal plates that allow for growth of the skeleton after birth
- Provides smooth articular surfaces for joints
- Absorbs shear forces or shock forces in some joints
Describe hyaline cartilage
Most abundant cartilage in the body
-Collagen fibers thin not visible
- Chondrocytes in lacunae
- Outer surface covered by perichondrium (except articular cartilage )
What are the functions of hyaline cartilage ?
Provides flexibility, shock absorption and support
- found in trachea, bronchus, larynx, epiglottis , ends of ribs
- Articular cartilage reduces friction for joint surfaces
Describe fibrocartillage
Chondrocytes scattered among thick bundles of collagen fibers in extracellular
- No perichondrium
- Combines strength and rigidity
Where is the fibrocartilage found?
Articular discs (intervertebral, symphysis pubic, meniscus, TMJ)
Describe elastic cartilage and give its function
- Chondrocytes located in a threadlike network of elastic fibers in extracellular matrix
- Provides strength and elasticity and maintains shape e.g. external ear, tip of nose
Contrast and compare growth and repair
- Once fully formed cartillage is relatively inactive and grows slowly
- Repairs is slow and often fails because its Avascular
What are the types of growth?
Interstitial Growth
-initial type
-mainly hyaline
Appositional growth
What is interstitial growth?
Initial type for all cartillage
Growth within tissue
Rapid due to cell division and increasing amounts of extracellular matrix
-Chondrocytes are pushed away from each other
What is appositional growth?
Follows interstitial growth
- Occurs on outer surface
- perichondrium cells differentiate into chondroblasts
- As cells produce extracellular matrix they turn into Chondrocytes
- Results in increase in width of the structures
- Occurs in all cartillage except fibrocartilage and Articular cartilage
What is osteoarthritis?
- Age related degeneration of Articular cartilage followed by failed attempts at repair
- The cartilage b3comes thin and weak resulting in tears
- In a attempt to repair, bone Spurs form decreasing the joint space
- Affects mainly large weight bearing joints
Define bone
Specialized connective tissue with cells (osteocytes) and extracellular matrix (mineralized)
What are the types of bones?
Different types of bones serve different functions
- Protection, support, levers, weight bearing etc.
- Categorized based on shape
What are osteoblasts?
Bone cells/osteoblasts- produce bone matrix and become osteocytes when trapped in lucanae
- Osteocytes maintain bone matrix and are connected to adjacent cells by cytoplasmic processes in canaculi
- Influenced by hormones
Summarize osteoblasts formation
Osteogenic cell (develops into an osteoblasts) —> osteoblast (forms bone extracellular matrix) —> osteocytes (maintains bone tissue)
What are osteoclasts?
- Large, multinucleated cells responsible for breakdown and resorption of bone matrix during remodeling
- Influenced by hormones
What are the two types of bone tissue?
- compact (dense, thick, few spaces)
- Spongy (many spaces, often continuous forming marrow cavity)
What is inside bone?
Inside of bones contain spaces that allow for vessels to enter and supply cells or as storage areas for marrow
Is bone living tissue?
Bone tissue is a complex and dynamic living tissue- under constant remodeling
Describe long bones
Shaft with two extremities
- diaphysis
- epiphysis
- metaphysis
Outside layer of compact bone with spongy bone inside
Marrow filled red (RBC ) or yellow marrow (fat)
-outer surface covered with periosteum (except Articular surfaces)
Long bones have a rich blood and nerve supply
-fracture = pain, blood loss
-nutrient foramen~ mid shaft for nutrient artery
Describe compact(dense bone)
Strong with few spaces covered by periosteum
- mature bone is composed of cylindrical units called osteons (Haversian systems)
- Concentric lamella of bone matrix
- Lacuna between layers
- Connected by canaculi
- Central canal containing vessels (aversion canal)
- connected to each other by volkmans canals
- Continually being remodeled - Remnants of osteons= interstitial lamella - Concentric lamella of bone matrix
Long axis of osteon is parallel to the long axis of the bone
Describe bone lining cells
Contains large spaces
- Has trabeculae of lamellated matrix
- Makes up majority of tissue on the inside of short, flat and irregular bones
- forms a marrow rim around the medullary cavity of long bones
- Reducing the overall weight of bone
- supports the bone marrow
