Musculoskeletal system

• The Axial skeleton

  is the midline of the body and consists of the skull and the vertebral column (spine) laryngeal skeleton and thoracic cage
• The Appendicular skeleton

  includes all the bones that form the upper and lower limbs, and the shoulder and pelvic girdles
• name the long bones

  humerus, radius, and ulna for the arm

  femur, tibia and fibula in the leg

  phalanges in the feet and hand
• long bones function

  theses bones support the weight of the body and provide attachment for powerful muscles that enable movement
• short bone types

  carpals and tarsals of the feet and hands
• short bones function

  these bones provide stability and some(although very little) movement
• flat bones types

  sternum, ribs and bones that form the cranium, which hold the brain
• flat bone function

  they provide protection
• irregular bones types

  the vertebrae and the bones that make up the pelvis
• irregular bones function

  their shapes help to protect internal organs
• sesamoid bone types

  the largest is the patella however smaller ones are found in the feet and hands
• sesamoid bones function

  they develop in tendons to protect the parts that lie over and tendon itself.
• function of Skelton support: keeps the body upright even in movement and supports soft tissue and skin
• function of Skelton protection: forms a hard case over vital organs like the brain and spinal cord, heart, lungs, liver and reproductive organs
• function of Skelton attach to muscles : to produce movement, muscles must be attached at both ends and lie over a joint. The fibrous ending of a muscle is the tendon and this merges strongly with the outer surface of a bone.
• function of Skelton blood cells : the bone marrow found in the shafts of the ribs, sternum, vertebrae and the heads of long bones contain many stem cells that can develop into all the different types of blood cells, including erythrocytes (red blood cells) and lymphocytes (white blood cells) that are involved in the immune response
• function of Skelton mineral : bone is a store of both calcium and phosphate and interchange occurs when needed between bone and blood levels
• calcium: in the bone is important as it is involved in nerve conduction, muscle contraction and blood clotting.
• Phosphate: is important as it is a major component of DNA and is also involved in energy metabolism
• Cartilage is what the foetal skeleton is made up of to begin with and as the bone tissue increases after birth up to adolescence it does so from a plate of cartilage (growth plate) just below the head of each bone.  This is called the epiphysis or epiphyseal cartilage
• Ligaments are strap like bands of fibrous connective tissue that run from bone to bone across a joint. They are made of yellow, elastic fiber's of protein and have a limited degree of stretch. 
• ligaments function: is to partly hold the joint together but also to prevent overstretching at the joint
• Fibrous joints – they are connected by dense connective tissues consisting mainly of collagen.  These joints are called fixed or immovable joints because they do not move. E.g between the bones of the skull
• Cartilaginous joints – which allow little movement e.g. pubic symphysis
• Synovial joints – these are the most common type of joint, they are freely moveable
• Flexion – where the angle between 2 bones decreases, as in touching the shoulder with the same arm
• Extension – where the angle between 2 bones increases, such as straightening the arm after flexion
• Circumduction – turning a limb 360 degrees, for example ‘windmilling’ the arm in a circle
• Abduction – moving the arm or leg away from the central trunk
• Adduction – the opposite of abduction, returning the limb towards the central trunk
• Gliding – sliding 1 bone against another, for example the inteverterbral joints and the small bones of the ankles and wrist.
• Tendons are inelastic soft tissues made of strong collagen fibres and is designed to withstand tension.  Tendons and muscles work together to move bones. tendons are inelastic otherwise movement would be hindered. Overstretching them may weaken the joints integrity and cause destabilization which increases the risk of injury.
• Fascia is a strong, often thick sheet of areolar tissue to which smaller muscles can be attached, such as the muscles responsible for facial expressions
• types of contraction

  • Concentric- muscles contracts and shortens
• types of contraction

  • Concentric- muscles contracts and shortens
  • Eccentric- muscles contracts but lengthens due to the load
  • Isometric- Contracts but remains the same length due to the load
• Agonist/prime mover – the main contracting muscle in a movement
• Antagonist – the muscle opposite the agonist, it relaxes to allow the agonist  to move the bone
• fixator – a muscle that holds surrounding bones and joints steady to form a stable base for the movement
• Synergist – a muscle that cooperates in a movement but is not the agonist, it also stabilises the movement.  Synergist comes from synergy, ‘working together’