Lecture 5: Bones, Joints, Ligaments & Tendons Flashcards
Cartilage
- Supportive connective tissue
- Joint surfaces
- Ears, nose, vertebral disc
Ligaments
- Dense regular connective tissue
- Anchor bones to other bones
Tendons
- Dense regular connective tissue
- Anchor bones to muscles
What type of matrix do cartilage and bone have?
Dense, solid matrix
Hyaline Cartilage
- Proteoglycans
Elastic Cartilage
- Proteoglycans and Elastin fibres
Fibrocartilage
- Proteoglycans and lots of collagen
What do all three subtypes of cartilage have in common? (hyaline, elastic, and fibrocartilage)
- AVASCULAR
- Contain chondrocytes residing in lacunae
Compact Bone
- Dense (heavy), resists compression
- Organized in concentric circles
Spongy Bone
- Light, distributes force
- Ends of long bones
- Muscles won’t have to work as hard due to combination of spongy and compact)
Bone Tissue
Highly vascularized, innervated
Bone Marrow
- Not a type of supportive connective tissue
- Creates blood cells
Endosteum
Inner membrane of bone
Periosteum
Outer membrane of bones
Osteogenic Cells
Produce other bone cells
Osteoblast
Produce bone matrix
Osteocytes
Maintain bone matrix
Osteoclasts
Dissolve bone matrix
Cartilage can grow through what two methods?
Interstitial Growth - Cell division (chondrocyte proliferation)
Appositional Growth - Differentiation
Interstitial Growth
- ChondroCYTE undergoes division
- Additional matrix secreted, pushes cells apart
Appositional Growth (Cartilage)
- Cells differentiate onto chondroblasts
- Chondroblats secrete new matrix
- Chondroblasts mature into chondrocytes
What are the two mechanisms bone can grow via?
- Endochondral growth
- Appositional growth
Endochondral Growth
- Most bone begin (in utero) as hyaline cartilage
- Ossification begins at the shaft (Diaphysis)
- Ossification starts at the epiphyses (ends)
- Not possible after puberty
Appositional Growth (Bone)
- Additional circumferential lamellae are deposited and the bone continues to increase in diameter
- Osteoblast active at the periosteum
- Osteoclasts active at the endosteum
Dermal and Sesamoid Bones
- Ossify from non-cartilaginous connective tissue
Dermal Bones
- Found mostly in the head
- Ossify within dermal tissue (dermis layer)
Sesamoid Bones
- Form within tendons (EX: patella)
Synarthrosis
- No movement
- Fibrous: Sutures and Gomphosis
- Cartilaginous: Synchondrosis (rib to sternum)
- Bony: Synostosis ( middle of frontal bone)
Amphiarthrosis
- Little movement
- Fibrous: Syndesmosis (Ligaments)
- Cartilaginous: Symphysis (Pubic Symphysis)
Diarthrosis*
- Free movement
- Synovial
Synovial Joints
- Most complex
- Involve several tissues like bone and hyaline cartilage
Articular Cartilage
Sub-type of hyaline cartilage
Bone Tissue Repairs
- Bone healing involves extra proliferation of cells
- Typically first differentiate into cartilage (callus)
Cartilage –> Spongy Bone –> Compact Bone
Why can’t articular cartilage undergo self-repair
Llacks perichondrium layer
Osteoarthrotis
Caused by damage to articular cartilage
- Damage increases friction at synovial joint leading to inflammation, pressure, and more damage
How do bones act as a reservoir for minerals within your body?
- The ability of bone to be actively remodelled by cellular activity allows it to store or release minerals as they are needed
Calcium Homeostasis
The balance between amount of osteoblast and osteoblast activity helps maintain calcium homeostasis
