Joints, Synovial Fluid and Cartilage Flashcards
What are the 3 types of joints?
Fibrous
Cartilaginous
Synovial
What are examples of fibrous joints?
- Cranial sutures
- Periodontal ligament
- Interosseous membranes
What are the different categories of cartilaginous joints?
- Primary cartilaginous joint (synchondrosis)
- Only hyaline cartilage
- Secondary cartilaginous joint (symphysis)
- Hyaline and fibrocartilage
What type of cartilage is present in synchondrosis cartilage joints?
Only hyaline cartilage
What type of cartilage is present in symphysis cartiliginous joints?
Hyaline and fibrocartilage
What are primary cartilagnious joints also known as?
Synchondrosis cartilaginous joints
What are secondary cartilaginous joints also known as?
Symphysis cartilaginous joints
What are some of the features of a synovial joint?
What are the different kinds of synovial joints?
Plane
Hinge
Pivot
Condylar
Saddle
Ball and socket
Joint stability is achieved by what?
- Shape of articulating surfaces
- Capsule and ligaments
- Muscles
What is hyaline cartilage also known as?
Articular cartilage
What are the different layers of articular cartilage in a synovial joint?
- Superficial/tangential layer
- Flattened chondrocytes that produce collagen and glycoproteins (such as lubcricin)
- Transitional layer
- Round chrondrocytes that produce proteoglycans such as aggrecan
What is produced in the superficial layer of articular cartilage in a synovial joint?
- Flattened chondrocytes that produce collagen and glycoproteins (such as lubcricin)
What is produced in the transitional layer of articular cartilage in a synovial joint?
Round chrondrocytes that produce proteoglycans such as aggrecan
How does the orientation of collagen in articular cartilage in a synovial joint change from superficial to deep?
- Change in collagen orientation from superficial to deep layers
What percentage of articular cartilage is water?
>75%
What are some categories of molecules formed from carbohydrates and water?
-
Glycoproteins
- Such as lubricin
- Proteins to which oligosaccharide chains are attached (so more protein than carb)
-
Proteoglycans
- Such as aggrecan
- Proteins that are heavily glycosylated (protein core to which one or more GAGs attach)(tend to be more carbs than protein)
-
Glycosaminoglycans or GAGs
- Such as hyaluronic acid
- Long unbranched polysaccharides which are highly polar and thus attract water
What kind of molecule is lubrican?
Glycoprotein
What is a glycoprotein?
- Proteins to which oligosaccharide chains are attached (so more protein than carb)
What kind of molecule is aggrecan?
Proteoglycan
What is a proteoglycan?
- Proteins that are heavily glycosylated (protein core to which one or more GAGs attach)(tend to be more carbs than protein)
Do proteoglycans tend to have more carbohydrates or proteins?
Carbohydrates
What does GAGs stand for?
Glycosaminoglycans
What kind of molecule is hyaluronic acid?
Glycosaminoglycan
What are Glycosaminoglycans (GAGs)?
- Long unbranched polysaccharides which are highly polar and thus attract water
What is the average thickenss of articular cartiage in synovial joints?
- Average 2-3mm
- Interphalangeal joint 1mm
- Patella 5-6mm
Decribe the vascularity, nerves and lymphatics of cartilage?
- Avascular
- Aneural
- Alymphatic
What is synovial fluid produced by?
Synovial fluid is produced by synovial membrane (synovium)
How does direct exchange of oxygen, CO2 and metabolites take place with cartilage?
Direct exchange of oxygen, carbon dioxide and metabolites is done between blood and synovial fluid
What cells in the synovium (synovial membrane) produces the fluid?
- Synoviocytes producing the fluid
- Different types, A
- Look like macrophages, remove debris
- Contribute to synovial fluid production
- B
- Fibroblast like
- Main producer of synovial fluid
- Different types, A
What type of synoviocyte is the main producer of synovial fluid?
Type B
Describe the capillary network and epithelial lining of the synovium?
- Rich capillary network
- No epithelial lining
What is synovial fluid formed from?
- Formed from hyaluronic acid and lubricin with a fluid component from blood plasma
What is the turnover of synovial fluid?
- Rapid turnover (about 2 hours)
What are some of the functions of synovial fluid?
- Nutrition of cartilage (articular c., menisci/discs)
- Removal of waste products
-
Lubrication -> less friction -> less wear
- Boundary
- Glycoproteins such as lubricin bind to receptors on articular surfaces to form a thin film
- Hydrodynamic (like aquaplaning)
- Surfaces kept apart by liquid pressure
- Viscosity changes with load and velocity of movement
- Weeping
- Fluid that is present in the cartilage is squeezed out into the synovial cavity to increase fluid volume
- Boundary
How does synovial fluid achieve its lubricating function?
- Boundary
- Glycoproteins such as lubricin bind to receptors on articular surfaces to form a thin film
- Hydrodynamic (like aquaplaning)
- Surfaces kept apart by liquid pressure
- Viscosity changes with load and velocity of movement
- Weeping
- Fluid that is present in the cartilage is squeezed out into the synovial cavity to increase fluid volume
What are bursae?
- Is a small fluid filled sacs lined by synovial membrane with an inner capillary layer of viscous synovial fluid
What is the function of bursae?
- Function is to reduce friction
What is inflammation of bursae called?
Bursitis
What happens to the viscosity of synovial fluid and the water content of cartlage as you age?
- Viscosity of synovial fluid increases
- Slower joint movements
- Reduced lubrication
- Water content of cartilage decreases
- Reduced shock absorption
What are consequences of the viscocity of synovial fluid increasing?
- Slower joint movements
- Reduced lubrication
What is a consequence of decreased water content of cartilage?
- Reduced shock absorption
What disease can be a consequence of ageing and its affects on synovial fluid and cartilage?
Osteoarthritis
