muscles and bones

• The skeletal system


  • The arms and legs allow movement
  • The skull, ribs and sternum protect
  • The pelvis and collarbone provide framework and further support
• Bones


  Living organs that can repair when they fracture or break
• Bones


  • Strong and hard to stand up to hard knocks
  • Light for easy moving
• Structure of bones


  1. Osteoblasts: circles of bones created by bone-making cells

  2. Compact bone material: hard and strong, makes a tube shape

  3. Spongy bone material: makes the bone lighter with holes

  4. Bone marrow: used to create blood cells and reduce the bone mass
• Types of bones


  • Ball and socket bone
  • Hinge bone
  • Fixed or fused joints
• Ball and socket bone


  Greatest range of movement is 360 degrees, one end of a bone is shaped like a ball that is fitted into a hollow socket in the end of another bone
• Hinge bone


  Allows movement in 2 directions with a limit, 2 bones join together at a point
• Fixed or fused joints

  No movement, the brain has 22 bones joined by fused joints
• Structures that join 2 bones to make a flexible joint

  • Tendon
  • Cartilage
  • Ligament
• Sprain


  Happens when a ligament is stretched or tears, can cause dislocation as the bone is out of line and the joint does not work
• Pulled muscle


  Happens when a muscle or tendon is stretched or gets a small tear
• Functions of the skeleton

  • Movement
  • Support
  • Posture
  • Protection
  • Production of blood cells
  • Mineral storage
• Cranium


  Protects the brain
• Ribs


  Protect the heart and lungs
• Pelvis


  Protects sensitive reproductive organs
• Vertebrae


  Protect the spinal cord
• Synovial joints


  Joints that allow a wide range of movement
• Different types of movement

  • Flexion
  • Extension
  • Adduction
  • Abduction
  • Rotation
  • Circumduction
• Locomotor system


  The organ system formed by our muscles and bones that helps us to move
• Biomechanics


  The study of how bones and muscles work to help us move
• Muscles


  • Organs that can contract, become smaller and fatter when contracting, release energy when contracting but not when relaxing, so can only pull
• Antagonistic pairs


  For a muscle to move a joint in 2 directions, one should contract and one should relax
• Functions of muscles


  • Joint stability
  • Generate heat
  • Movement
  • Maintain posture
• Muscle contraction


  Impulses from the brain sent down to the spinal cord and to the nerves attached to the muscle
• Tendons


  Connect the bone to the muscles, not elastic, stabilise or anchor the bone, change according to the size of the muscle
• Ligaments


  Slightly elastic, connect bone to bone, absorb shock due to elasticity, stabilise the joints during movement, maintain proper and correct posture
• Cartilage


  Covers the ends of the bones, tough and elastic, absorbs shock, produces synovial fluid, prevents the friction/wearing/tearing/rubbing of bones together
• Bones + muscles + ligaments + tendons = Musculoskeletal system
• Bones can be appendicular or axial.
• Appendicular bones - bones found in our arms, hips, legs and shoulders.
• Appendicular bones are mainly used to create movement and support body weight.
• Appendicular bones are predominantly long and short bones.
• Long bones are bigger bones found in our arms and legs. They support the weight of the body and support gross movements - big movements that require big body parts. Examples include Tibia, Fibula, Humerus, Clavicle.
• Short bones are smaller bones found in our hands and feet. They support fine movements (small controlled movements require smaller groups). Examples are tarsals and carpals.
• Axial Skeleton are the bones found in core of our body. They are used for protection of vital organs and predominantly irregular bones and flat bones.
• Flat bones are bones that provide a site for muscle attachment! Examples include the pelvis, cranium and ribs.
• Irregular bones include the vertebral column, so they do not have any irregular shape or fit into any category.
• Sesamoid bone is a bone embedded in the tendon, protecting the joint. Example is a patella.