Joints, synovial fluid & cartilage Flashcards
Functions of skeletal system
Describe dynamic movements of the skeleton
Distinguish between different types of joints + Link anatomical design to joint functions
Explain the structure + function of cartilage
indicate the mechanisms of nutrition of cartilage
Describe the main constituents of synovial fluid
Indicate the function of synovial fluid
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3 types of joints
Fibrous
Cartilaginous
Synovial
What do fibrous joints join
Bone to bone
- joint composed of fibrous connective tissue made of densely packed collagen fibres
Examples of fibrous joints
Cranial sutures Periodontal ligament Interosseus membranes (between radius and ulna, tibia and fibula)
Subtypes of cartilaginous joints
Primary cartilaginous (aka synchondrosis)
Secondary cartilaginous (aka symphysis)
What type of cartilage are
- primary cartilaginous (1)
- secondary cartilaginous (2)
joints made of
Hyaline cartilage (aka articular cartilage)
Hyaline & fibrocartilage
Examples of primary cartilaginous joints
Articular surfaces of bones
Epiphyseal growth plate
Examples of secondary cartilaginous joints
IV disc between vertebrae
Features of synovial joints
Fibrous capsule surrounding whole joint
Synovial membrane lining inner surface of capsule
Synovial cavity containing synovial fluid
Synovial joints may also contain
Articular discs
Ligaments
Bursae
Subtypes of synovial joints
Plane Condylar (ellipsoid) Hinge Saddle Pivot Ball and socket
Features that make a joint stable
Shape of articulating surfaces
Capsules & ligaments
Muscles
Describe the cells in the
- superficial/tangential layer
- transitional layer
of articular cartilage
Flattened chondrocytes that produce collagen and glycoproteins
Round chondrocytes that produce proteoglycans, e.g. aggrecan
Percentage water content of articular cartilage
> 75%
How does the orientation of collagen fibres change as you go deeper down the layers of articular cartilage
From parallel to oblique to more vertical
Glycoproteins
- produced by
- what are they
- protein to carbohydrate ratio
- example
Flattened chondrocytes in the superficial layer of articular cartilage
Proteins to which oligosaccharide chains are attached
More a protein than a carbohydrate
E.g. lubricin
Proteoglycans
- produced by
- what are they
- protein to carbohydrate ratio
- example
Round chondrocytes in the transitional layer of articular cartilage
proteins that are heavily glycosylated
More carbohydrate than protein
E.g. aggrecan
Function of aggrecan in cartilage
Very polar so good at binding to water
What are glycosaminoglycans (GAGs) + example
long unbranched polysaccharides, which are highly polar and thus attract water
proteoglycans are produced by proteins binding to GAGs
e.g. hyaluronic acid
Cartilage is avascular, aneural and alymphatic so how does it get nutrients and remove waste
Synovial membrane (synovium) lining the inner surface of the fibrous capsule has a rich capillary network that allows exchange of gases and metabolites between blood and synovial fluid
Synovial fluid produced by
Synoviocytes in the synovial membrane (synovium)
Type A v B synoviocytes
Type A
- look like macrophages
- remove debris
Type B
- fibroblast like
- main producer of synovial fluid
Constituents of synovial fluid
Hyaluronic acid & lubricin Fluid component (from blood plasma)
How many hours is synovial fluid turnover
around 2 hrs
Functions of synovial fluid
Nutrition of cartilage
Remove waste products
Lubricate–> less friction
What are bursae
Fluid filled sacs that reduce friction
Effect of ageing on
- synovial fluid
- water content of cartilage
Viscosity of fluid increases –> slows velocity of movements
Water content decreases –> reduces shock absorption
