MSK physiology 2 Flashcards
What are the 3 main types of joints?
- Synovial
- Fibrous
- Cartilaginous
What are fibrous joints and give an example of one?
Fibrous joints are bones united by fibrous tissue, these joints dont allow any movement.
An example is theb joints which join the bones of the skull in adults.
Define what cartilaginous joints are, what range of movement do these joints allow?
They are bones united by cartilage - they allow limited movement.
Give some examples of cartilaginous joints
Intervertebral Discs; Pubic symphsis; Part of the sacroiliac joints; Costochondral joints
Define what a synovial joint is
Bones separated by a cavity (containing synovial fluid) and united by a fibrous capsule (and other extra-articular structures e.g. ligaments, tendons, and bursae)
What is the inner aspect of the fibrous capsule in a synovial joint lined by?
synovial membrane -is vascular connective tissue with capillary networks and lymphatics
What produces synovial fluid ?
The synovial membrane(synovium) contains synovial cells (fibroblasts) which produces the synovial fluid.
What is the two different types of synovial joints?
Simple - only one pair of articular surfaces e.g. metacarpophalangeal joints
Compound - more than one pair of articular surfaces e.g. elbow joints
What are the two overall physiological role of joints?
structural support and purposeful motion
What are the more specific role of joints during purposeful motion ?
Stress distribution
Confer stability - shape of articular component e.g. the hip joint, ligaments, synovial fluid
Joint lubrication provided by - Cartilage interstitial fluid, Synovium - derived hyaluronic acid, Synovium-derived lubrcin
What are the functions of synovial fluid ?
Lubricates the joint which inturn facilitates movement and reduces wear and tear by reducing friction.
Aids in nutrition of articular cartilage - supplied chondrocytes with O2 and nutrients and removes CO2 and waste products.
What are the general characteristics of synovial fluid ?
- Fills the joint cavity
- Continually absorbed anmd replenished by synovial membrane (synovium)
- Has a high viscosity (due to presence of hyaluronic acid)
- Contains few cells (mainly mononuclear leucocytes)
What happens to the viscosity of synovial fluid during movement?
Rapid movement is associated with decreased viscosity and increased elasticity
What is the normal appearance of synovial fluid ?
clear and colourless
What happens to the synovial fluid WBC in inflam and septic arthritis ?
WBC increases
What happens to the appearance in traumatic synovial tap and haemorrhagic arthritis ?
synovial fluid turns red
Match the description to the appearance of the synovial fluid:
- A.
- B.
- C.
- D.
- Normal synovial fluid. It is viscous and clear
- Synovial fluid obtained from a severely inflamed joint. It is thin and opaque due to a very high polymorph count
- Synovial fluid from joint with mild synovial inflammation
- Synovial fluid from joint with mild synovial inflammation. The blood stain is caused by trauma
A.Normal synovial fluid. It is viscous and clear
B.Synovial fluid from joint with mild synovial inflammation
C.Synovial fluid from joint with mild synovial inflammation. The blood stain is caused by trauma
D.Synovial fluid obtained from a severely inflamed joint. It is thin and opaque due to a very high polymorph count
What are the main functions of articular cartilage ?
- Provides a low friction lubricated gliding surface. This helps prevent wear-and-tear of joints.
- Distributes contact pressure to subchodral bone.
The articular cartilage is usually hyaline, it covers articular surfaces, it has a special ECM which is comprised of what?
70% water
20% collagen (mainly type II) - contributes most to the elastic behaviour of cartilage.
10% proteoglycan
What are the mechanical properties of water in cartilage ?
- Maintain the resiliency of the tissue and contribute to the nutrition and lubrication system
- Highest conc near articular surface
What are the mechanical properties of collagen in cartilage ?
- Maintain cartilage architecture
- Provides tensile stiffness and strength
What are the mechanical properties of proteoglycan in cartilage and where is the highest conc of proteoglycan in cartilage ?
–Highest concentration is found in the middle and deep zone
–Responsible for the compressive properties associated with load bearing
The ECM is synthesized, organised, degraded and maintained by what?
chondrocytes (cartilage cells)
Changes in the amount of the 3 major components of cartilage can change the mechanical properties of cartilage what is another way in which joint disease can occur ?
If the rate of ECM degradation exceeds the rate of its synthesis
What are the catabolic and anabolic factors influencing cartilage ECM turnover?
Catabolic factors
–Stimulate proteolytic enzymes and inhibit proteoglycan synthesis
- •Tumour necrosis factor (TNF)-a
- •Interleukin (IL)-1
Anabolic factors
–Stimulate proteoglycan synthesis and counteract effects of IL-1
- •Tumour growth factor (TGF)-β
- Insulin-like growth factor (IGF)-1
What are the 2 markers of cartilage degradation ?
Increased Serum and synovial keratin sulphate
Increased levels of type II collagen in synovial fluid
What goes wrong in a joint resulting in OA?
Cartilage and synovial composition and function deteriorate with age and repeated wear and tear giving rise to osteoarthritis.
What goes wrong in a joint giving rise to RA?
Synovial cell proliferation and inflammation cause rheumatoid arthritis
What goes wrong in a joint to cause gouty arthritis ?
Deposition of salt crystals e.g. uric acid
Injury and inflammation to periarticular structures causes what?
soft tissue rheumatism e.g. injury to tendon causes tendonitis
