Skeletomuscular System - Bone and Cartilage Flashcards
What is the skeletomuscular system?
System that connects the skeleton to muscles - the skeleton and muscles work together to support the body’s weight and allow it to move
What are the functions of the skeletal system?
- provide support
- protects tissues
- stores minerals
- forms blood cells
What type of tissue makes up the skeletal system?
Connective tissues
What are the three types of connective tissue structures that connect the skeletal and muscular systems?
Cartilage - supportive connective tissues
Tendons - dense regular connective tissue
Ligaments - dense regular connective tissue
What do cartilage and bone have in common?
SUPPORTIVE CONNECTIVE TISSUE WITH DENSE SOLID MATRICES
CARTILAGE: chondrocytes in lacunae
BONE: osteocytes in lacunae
CARTILAGE: chondroitin sulfate (in proteoglycan)
BONE: small volume of liquid surrounded by crystals of calcium salts (crystalline)
CARTILAGE: collagen, elastic, and reticular fibers in varying proportions
BONE: collagen fibers predominate
CARTILAGE: no internal blood vessels (avascular)
BONE: extensive blood vessels (extensive vasculature)
CARTILAGE: perichondrium covering (two layers)
BONE: periosteum covering (two layers)
CARTILAGE: limited strength; ends easily; but hard to break
BONE: strong; resists distortion until broken
What makes up bone tissue? What are some of its characteristics?
- supportive connective tissue
- collagen + calcified, hydroxyapatite matrix
- more rigid
- mineralized, crystalline matrices
- highly vascularized and innervated
What makes up cartilage? What are some of its characteristics?
- supportive connective tissue found at joint surfaces
- proteoglycan matrix (glyco-proteins which include chondroitin sulfates)
- more flexible
- avascular and contain chondrocytes residing in lacunae
What are the three subtypes of cartilage?
- Hyaline cartilage
- Elastic cartilage
- Fibrocartilage
- all avascular and contain chondrocytes residing in lacunae
What are the two subtypes of bone tissue?
- Compact
- Spongy
- represent a trade-off between weight and weight-bearing
What is hyaline cartilage?
- contains proteoglycans
- stiff somewhat firm support
ex) shoulder joint
What is elastic cartilage?
- proteoglycans + elastic fibres
- can distort without damage and return to original shape
ex) external ear
What is fibrocartilage?
- proteoglycans + lots of collagen
- extremely durable and tough
- matrix consists mostly of collagen and less ground substance
ex) knee joint
What is compact bone tissue?
A bone is typically hollow
- bone tissue that lines the outside of the bone
- dense (heavy) resists compression
- supports weight
What is spongy bone tissue?
A bone is typically hollow
- network that lines the internal cavity of the bone
- light, distributes force
- reduces weight
What are chondrocytes?
aka cartilage cells - found in chambers called lacunae
- responsible for production of collagen and extracellular matrix
- maintenance of cartilaginous tissues within joints
What are proteoglycans?
proteins present in the extracellular matrix of connective tissues (cartilage)
What is bone marrow?
- fills the cavities/inside spaces of bones
- NOT a type of supporting connective tissue
- creates blood cells (erythrocytes, etc.)
What are the four types of cells in bone tissue?
- osteogenic cells
- osteoblasts
- osteocytes
- osteoclasts
What are osteogenic cells?
- found in the periosteum for adults
- deep layers of the periosteum and the marrow (inner, cellular layer of the periosteum, and sometimes in the endosteum)
- stem cells that produce other bone cells
- play a role in bone repair and growth
- divide to produce daughter cells that differentiate into osteoblasts
- maintain populations of osteoblasts
What are osteoblasts?
- secrete collagen hydroxyapatite
- produce new bone matrix in a process called ossification/osteogenesis
- found along the bone surface
- immature cell
What are osteocytes?
- matured osteoblast/mature bone cell
- found between bone layers
- maintain bone matrix
- secrete chemicals that dissolve the adjacent matrix and release minerals into bloodstream (then they rebuild the matrix)
- located within lacunae surrounded by mineralized bone matrix
What are osteoclasts?
- breaks the bone / dissolves the bone
- remove bone matrix (osteolysis)
- found in the endosteum (inner)
- degrade bone to initiate normal bone remodeling
- play a role in bone growth
What do bone and cartilage have in common?
- both have solid matrices
- only bone has mineralized crystalline matrix
- both have cells capable of synthesizing matrix and matrix proteins
- both can sometimes be found within bones
What question should you ask yourself to differentiate cartilage from bone tissue?
How is the tissue formed and how does it grow?
Answering this question can help us determine if we are referring to bone tissue or cartilage!
What are the two ways that cartilage grows?
- Cell division - Interstitial growth
- chondrocyte proliferation - Differentiation - appositional growth
- differentiation into new chondrocytes
What is interstitial growth?
- chondrocyte proliferation
- growth by chondrocyte
- not possible after puberty
- chondrocyte undergoes division and the additional matrix secreted pushes the cells apart
- lay down more matrix in the existing matrix and this is what allows the cartilage to grow