Three types of joint
Synovial, Fibrous, Cartilaginous
Example of fibrous joint
Sutures in the skull
Examples of cartilaginous joints
IV discs, costochondral joints, pubic symphysis, part of the sacroiliac joint
What is the synovial membrane?
a vascular connective tissue with capillary networks and lymphatics. It contains synovial cells (fibroblasts)
Definition of a simple synovial joint
has only one pair of articular surfaces
Definition of a compound synovial joint
has more than one pair of articular surfaces
3 Roles of joints during movement
- Stress distribution 2. Conferring stability 3. Joint lubrication
Where is the greatest share of stress distributed within a joint?
Across the muscles and tendons crossing the joint
How does a joint confer stability?
the shape of the articular components and the ligaments providing stabilisation.
What provides joint lubrication? (3)
- cartilage interstitial fluid 2. synovium derived hyaluronic acid 3. synovium derived lubricin
Functions of synovial fluid (3)
- lubricates the joint preventing wear and tear 2. aids in the nutrition of the articular cartilage 3. supplies the chondrocytes with O2, nutrients and removes waste
What causes the high viscosity of synovial fluid?
hyaluronic acid
Cells found in synovial fluid
mononuclear leucocytes - very few cells found though
3 main components of the articular cartilage ECM
Water, type II collagen, proteoglycan
What is a motor unit?
a single a-motor neuron and all the skeletal muscle fibres it innervates
What does the no. of fibres per motor unit depend on?
the function serve by a muscle
An example location of a motor unit with few fibres per a-motor neuron might be?
the eye - precision matters more
An example location of a motor unit with many fibres per a-motor neuron might be?
the thigh muscle - power is more important than precision
How are myofibrils arranged within the muscle fibre?
into sarcomeres
