1.1 Basic anatomy Flashcards
What are synathroses and Amphiarthroses?
Syn: an interlocking suture line between adjacent bones
Amp: fibrocartilage between adjacent bones
What are the 3 types of synovial joints?
Hinge, ball and socket and saddle
What is the synovium and what does it not cover?
The internal lining of the joint, does not cover the cartilage or meniscus unless it is pathological
What are the layers of the synovium and what is their function?
Inner: synoviocytes which are 3 cells thick and produce hyaluronic acid
Outer: subintima which produces fibroblasts
What is synovial fluid and what does it carry?
An ultrafiltarte of blood which has the hyaluronic acid to increase viscosity to allow the sliding of bones.
Acts as a lubricant and nutrient transport
What is synovitis?
An immune attack on the synovium such as that seen in RA
What happens in early RA?
oedematous, thickened, hyperplastic projections. Dense infiltration with inflammatory cells
What happens in late RA?
Pannus formation - hyperaemic, fibrovascular granulation tissue in the joint causing loss of bone and cartilage
What is the role of fibrocatilage?
Attaches tendons and ligaments to bone
Where is fibroelastic cartilage located?
IV discs and intraarticular menisci (load bearing and shock absorption)
Where is articular cartilage located, what is its function and what are the key cells?
Locates at the ends of bones in synovial joints and acts as a shock absorber. The main cell type is the chondrocytes which synthesise the ECM (ground substance)
What type of collagen is in articular cartilage and what is its orientation
Type 2 collagen
Superficially they run parallel to the surface, intermediate no direction and deep they are vertical
Where do the collagen fibres come from in the articular cartilage?
they hold down the articular cartilage to the calcified cartilage which is related to the subchondral bone
What is the tidemark?
Where the calcified and normal cartilage meet
What are the components of ground substance and what is their function?
proteoglycan and elsatin
Act to bind the water in the cartilage, if you have degeneration in this you will lose water in the cartilage and the force that they transmit is lost leaving the force to be transmitted into the subchondral bone which has pain fibres
What cells secrete proteoglycans?
Chondroitin and keratin sulphate
Where are the 5 main types of collagen located?
1: skin, fascia, tendon, ligament, bone
2: cartilage
3: skin, artery and uterus (in combination with 1)
4: basement membrane
5: placenta and blood vessels
what is the function of collagen?
Determines the tensile strength of tissues
Provides a framework
Limits movement of other tissue components
Induces platelet aggregation and clot formation
Regulates hydroxyapatite deposition in bone
What is the composition of ligament and what is its function?
Dense collagenous tissue with rows of fibroblasts within and ECM of type 1 collagen fibres with elastin to allow for stretch
Function: to prevent excessive movement
What is the role of a tendon?
Carry tensile forces and store energy
injury: tears or degenration
What is the structure of a tendon?
parallel layers of collagen embedded in a matrix of proteoglycans
What happens in degeneration of tendons
There are no inflammatory cells leading to collagen fibre disorganisation and separation (microtears)
What is the structure and function os tenon sheath?
outer fibrotic layer and inner synovial layer with synovial fluid between the layers
Acts to reduce friction
What is paratenon and epitenon?
Paratenon: loose, arolar conective tissue around tendons
Epitenon: fine connective tissue sheath covering the tendon
Made of type 1 and 3 collagen fibres
What is the enthesis and what are the 4 zones?
Attachment point of the tendon/ligament to bone
Tendon/ligament, fibrocartilage, mineralized fibrocartilage and bone
The collagen bundles of the tendon continues into the fibrocartilage and the tidemark will separate this from the mineralized fibrocartilage
