Anatomy of the skeletal system

• Where are long bones found?

  In the limbs
• What is the primary function of long bones?


  To support body mass and to create large movements.
• One example of a long bone is the femur. What does the femur do apart from support body mass?

  Crucial for producing bone marrow, essential for blood cell production.
• Anatomy of bone diagram

  
• Periosteum - the tough outermost layer of the bone
• Bone minerals - such as calcium and and phosphorous are stored within the bone. Essential for bone creation and reabsorption of bone tissue.
• Bone marrow soft and spongy tissue 2 types: red bone marrow which produces red blood cells, white blood cells and platelets or yellow bone marrow which produces fat and cartilage.
• Epiphysis - the rounded end of the bone, it commonly forms an articulation or joint with another bone.
• Diaphysis - the central shaft or long part of the bone
• Growth plates (epiphyseal plate) - a disc of cartilage found at the end of each long bone of children and adolescents. Only places where an increase in bone length can take place. Once growing is stopped is replaced by an ephiphyseal line.
• Cancellous bone - spongy bone found within the ends of the long bone it provides space for the red bone marrow inside the bone structure.
• Compact bone - the hard tissue surrounding the bone and often referred to as 'cortical bone'
• Articular cartilage - the ends of long bones are covered with articular cartilage, allowing bones to move over each other with minimum friction.
• Medullary cavity - the space in a bone where marrow is stored
• Long bones have many distinct regions due to the way they develop these include: notches, fossas, condyles, borders, processes and tuberosity.
• Notches - the V shaped depressions at the edge of a flat area
• Fossas - shallow depressions on the surface of the bones which commonly receive another articulating bone were a joint is formed.
• Condyles - rounded bumps or large rounded prominences which usually fit into fossa on another bone to form a joint
• Borders - the main portion of the bone
• Processes - raised areas or projections that can be used to attach connective tissue.
• Tuberosity - a large rounded projection that looks like a raised bump. Tuberosities are often sites for muscle attachment.
• Ossification - bone remodelling. During this process parts of the bone are reabsorbed, so unnecessary calcium is removed(via cells called osteoclasts) while new layers of bone tissue are created.
• Osteoblasts - responsible for creating bone matter and bring calcium to your bones.
• Why does osteoblast activity increase when you do exercise?


  So that your bones will become stronger the more exercise you do. Bone calcium stores increase to cope with the demand for calcium, so exercising also reduces the risk of osteoporosis.
• Osteoclasts - cells that destroy or clean away old bone. Unnecessary calcium is removed via the osteoclats while new layers of bone tissue are created
• Osteoblasts - cells that build bone by bringing calcium to the bones
• Osteocytes - cells that grow the tissue, they form osteoblasts and make up the majority of mature bone matter.
• Why is vitamin D needed?


  To enable the absorption of calcium into the bones. Without vitamin D bones will become weak because existing stores will be used to maintain bone structure and cannot be replaced by new calcium found in the diet
• What are the functions of the skeletal system?

  use the bones to act as levers, provide attachment for muscles, tendons and ligaments. Produce blood cells from within bone marrow.
• Location of bones

  
• Axial skeleton - the axis of the body providing a core for the limbs to hang from.
• The axial skeleton is made up of: The skull, the thoracic cage (sternum and ribs) and the vertebral column
• Appendicular skeleton - includes the bones of the shoulder girdle, the pelvic girdle, the upper limbs and the lower limbs
• What are the types of bones?

  Long bones, short bones, flat bones, irregular bones and sesamoid bones.
• Long bones - have growth plates at either end, have an outer surface of compact bone and main function: to provide strength and speed in the body's movement
• Short bone - small, light, strong and cube-shaped. Function: offer support and stability with limited movement
• Flat bone - Features: a strong flattened plate, slightly curved, which provides the base for muscular attachment. Function: to protect vital organs as well as providing an attachment for muscles to help movement. E,g cranium, sternum and scapula
• Irregular bone - Features: mainly consist of cancellous bone with an outer layer of compact bone, with complex shapes. Function: irregular bones provide shape and protection. E.g the vertebrae
• Sesamoid bone - Features: bone inside a tendon where the tendon passes over a joint. Function: provides a smooth surface for the tendon to slide over. E.g the sesamoid
• What are ligaments?


  The connective tissue that holds together the bones. They keep the bones in place, connecting and stabilising joints.