Skeletal System

• Skeletal System

  • The skeletal system refers to the framework of bones, cartilage, and ligaments in the body that provides support, shape, and protection to the organs and tissues.
  • The skeletal system is composed of 206 bones in the adult human body, which are connected by joints and held in place by ligaments and tendons.
• Type of Bones

  1. Long bones : longer than they are wide and thin (e.g. Femur and Humerus)
  2. Short bones: equal in length and width and provide support and stability to the joints (e.g. Carpal bones).
  3. Flat bones: thin and flat and provide protection to the organs and tissues (e.g. skull and sternum)
  4. Irregular bones: have complex shapes and functions (e.g. vertebrae and facial bones)
  5. Sesamoid bones: small bones that are embedded in tendons (e.g. patella)
• Bones are made up of two types of tissue

  1. Compact bone - dense and provides strength and support
  2. Spongy bone – porous, provides cushioning and flexibility

  
• Cells in bone

  1. Osteocytes – maintains bone tissue matrix.
  2. Osteoblast – forms bone matrix.
  3. Osteogenic cell – origin cell of the bone.
  4. Osteoclast – resorbs/degrade bone.

  
• Types of Joints

  1. Fibrous joints - held together by dense connective tissue and allow for little to no movement (e.g. skull sutures).
  2. Cartilaginous joints - held together by cartilage and allow for limited movement, (e.g joints between the vertebrae).
  3. Synovial joints - allow for a wide range of movement and surrounded by a joint capsule filled with synovial fluid.