Structure and Function of Synovial joints Flashcards
What is Synarthrosis?
Immovable joints, the bones are in almost direct
contact but interspersed by connective tissue
What is Amphiarthrosis?
Slightly moveable joints, continuous osseous surfaces
connected by flattened discs of
fibrocartilage that allow for
limited movement
What is Diarthrosis (synovial joint) ?
freely moveable, possesses a cavity that
is lined by a synovial membrane.
- may or may not possess ligamentous and
meniscal structures internally.
- normally found between long bones.
What is Hyaline cartilage?
most common form of cartilage, contains holes where chondrocytes would have been
What is Fibrocartilage?
contains fibrous lines but it is sparse in cells, it is tough and dense but still very flexible
What is elastic cartilage?
chondrocytes plus elastic cartilage
what are chondrocytes?
main cells that make up cartilage, they can also produce a range of enzymes and local mediators
What is the extracellular matrix made up of?
Collagens and proteoglycans
What is the function of proteoglycans?
rigidity and stability
What are growth plates?
they allow longitudinal bone growth, contain cells in different stages of growth
what is the resting zone in growth plates
where chondrocytes rest
What is the proliferative zone in growth plates?
cells flatten and divide, chondrocytes begin to lay down the matrix
What is the hypertrophic zone in growth plates?
cells become larger there is a big increase in extracellular matrix, the cells eventually die and the invasion of blood vessels = start of bone growth
Synovium
specialized connective soft-tissue membrane that lines the inner surface of synovial joint capsules and maintains a sterile environment within the joint
What is the function of synovial fluid?
nourishes and lubricates the joint
What is the meniscus?
made out of fibrocartilage, the outer edge contains capillaries and nerve endings// highly organised collagen
What are ligaments?
They attach bone to bone
What are some examples of synarthrosis joints?
Immoveable joints found in the sockets of teeth
What is a function of the fibrocartilage disc?
allows for shock absorption in the amphiarthrosis joints
What is the joint space in a synovial space usually filled with?
Synovial fluid
What is the main type of collagen produced in the growth plates?
Type 10 collagen
What is synovial fluid rich in?
protein, glycans and hyaluronic acid
What is the function of the synoviocytes?
Filter the blood before it enters the joint
Which part of the meniscus contains the nerve endings and capillaries?
the outer part
What is articular cartilage?
Smooth white tissue that covers the ends of bones where they come together to form joints
What is the main function of chondrocytes?
They produce and secrete the extracellular matrix
What makes up proteoglycans?
Collagens and negatively charged glycosaminoglycans
What is the main reason why chondrocytes have a high water content?
water stays uncompressed and acts as a shock absorber
Where are synoviocytes found and what is their main function?
They are located in the inner surface of the joint cavity and remove debris by means of phagocytosis
What are the two meniscus found in the knee?
Lateral and Medial
What is the main collagen found in the meniscus?
Type II
What makes up ligaments?
Connective tissue with strong collagen fibres in it
Where are the neurons in a joint found?
Not in the joint itself but there are sensory nerves in the tissues surrounding the joint (also mechanoreceptors and nociceptors)
What joint is an example of a Synarthrosis joint?
Gomphoses or cranial joints
What is the joint space usually filled with?
Synovial fluid
What is one key note about articular cartilage
in terms of water content
Has a high water content
What is the perichondrium?
any area around the cell
What is one trait of cells in the resting zone?
They contain a lot of lipids
In what part of the growth plate will the cells die allowing blood vessels to invade?
Hypertrophic zone
What is the inner layer of the joint capsule known as?
The synovial membrane
What is the function of synovial fluid?
To reduce friction in the joint
What is the synovium?
lines the joint capsules
