Muscular Skeletal system

• Skeletal framework of the body


  • Consists of bone and cartilage
  • Functions to provide body support, protection and movement
  • Facilitated by the structure and function at cell and tissue levels

  
• Articulations of joints


  Classified according to their structure or the range of movements permitted
• Osteoporosis


  Disease, primarily of ageing, that causes disability
• Osteoarthritis


  Disease, primarily of ageing, that causes disability
• Increased understanding of the causes of osteoporosis and osteoarthritis leads to improved practices for management and prevention
• Functions of the Skeleton


  • Framework
  • Shape
  • Protection
  • Movement
  • Manufacture of blood cells
• Skeleton


  Rigid supporting framework of bones inside the body, to which all the soft tissues and organs are attached

  
• Together, the bones and muscles form a machine which can perform many different tasks
• Skeleton


  • Can grow in size
  • Can repair its own broken parts
  • Can lubricate its own joints
  • Can support internal organs
• Main types of bones in the human body


  • Long Bones
  • Short Bones
  • Flat Bones
  • Irregular Bones
  • Sesamoid Bones

  
• Long Bones


  • Different size and shape because they have different functions

  
• Diaphysis


  The main shaft of a long bone
• Epiphysis


  The end of a long bone

  
• Spongy bone


  Bone with an irregular latticework structure of thin plates called trabeculae

  
• Compact bone


  Very hard bone made up of regular concentric rings of bone tissue called osteons

  
• Compact bone contains blood vessels and nerve fibres

  
• Children have less inorganic matter in compact bone
• Old age has less organic matter in compact bone

  
• Spongy bone


  • Found in the epiphyses
  • Mixture of compact bone with pockets of bone marrow

  
• Bone marrow


  • Soft fatty material in the medullary cavity
  • Site for red blood cell production in young people
• Bone


  • Classified as a connective tissue
  • Has a brittle, calcified matrix with many collagen fibres, allowing bones to be pliable
  • Contains osteoblasts, osteocytes, and osteoclasts

  
• Haversian system


  Circular layers of bone (lamellae) surrounding a central Haversian canal, which carries blood and lymph vessels

  
• Osteocyte


  Mature bone cell embedded in a lacuna within the matrix
• Bone growth


  1. Increases in length due to growth plates made of cartilage

  2. Cartilage is continually formed and turned into bone (ossified)

  3. Growth plate ceases to function when the person becomes an adult

  4. Adults continually break down and build up bone

  
• Osteoclasts


  Remove damaged cells and release calcium into blood
• Osteoblasts


  Remove calcium from blood and build new matrix, becoming trapped as osteocytes
• Factors influencing coordination of osteoblasts and osteoclasts


  • Physical activity
  • Hormones
  • Diet
• Cartilage


  • Flexible material consisting of protein fibres (collagen) embedded in an extracellular matrix
  • Produced by chondroblasts which mature to become chondrocytes
• Types of cartilage


  • Fibrocartilage
  • Elastic Cartilage
  • Hyaline Cartilage
• Fibrocartilage


  Thick collagen fibres in bundles, no perichondrium, glistening white but opaque, can be compressed slightly, strongest type of cartilage
• Elastic cartilage


  Contains elastic and collagen fibres, has a perichondrium, yellowish hue, second most flexible cartilage, fewer chondrocytes than fibrocartilage
• Hyaline cartilage


  Closely packed collagen fibres for strength and flexibility, blueish white, has a perichondrium
• Ligaments


  Strong slightly elastic tissues that connect bone to bone

  
• Tendons


  Strong flexible inelastic fibres that connect muscle to bone, composed mostly of collagen
• Joint classification by structure


  • Fibrous
  • Cartilaginous
  • Synovial
• Joint classification by movement


  • Immovable
  • Slightly movable
  • Freely movable
• Immovable joints


  Allow no movement between the bones, function is strength and protection
• Slightly movable joints


  Allow a small amount of movement between the bones, example - joints between the vertebrae
• Freely movable joints


  Cartilage covers ends of bones with a gap between them containing synovial fluid, also called synovial joints

  
• Types of synovial joints


  • Ball and socket
  • Hinge
  • Gliding
  • Pivot
  • Saddle
  • Condyloid