EST BIOLOGY

• Skeletal system


  Structure and function
• Skeletal system


  • Supports and facilitates movement of the body
  • Structure and joints
  • Skeletal system
• Composition of human skeleton

  • 206 bones
  • Divided into two sections
• Axial skeleton


  • Consists of bones that lie around the central axis of body
  • Provides main support for erect posture
  • Protects the central nervous system and organs in the thorax
• Bones that form the axial skeleton

  • Skull
  • Ribs
  • Sternum
  • Vertebral column
• Appendicular skeleton


  • Consists of bones of upper and lower limbs
  • Pectoral girdle (shoulder)
  • Pelvic girdle (hip)
  • Allows for the articulation of the limbs with axial skeleton
• Skeletal system


  Made up of bones and their associated structures; tendons, ligaments and joints
• Functions of skeletal system

  • Provide scaffold to support weight and body
  • Facilitate movement by being attached to muscles
  • Protect vital internal organs
  • Produce red blood cells
  • Store and release minerals and fats
• The support and Movement of the body is facilitated by structure and function of the bones and joints in the skeletal system
• Long Bone


  • Consists of Hicroscopic struct one
  • Marcroscopic structure of long bones
  • Structure of compact bane
• Diaphysis


  Shaft making up main proportion of the bone, a hollow cylinder of compact bone surrounding Medullary cavity
• Epiphyses


  • Enlarged ends of bone, covered with a this longer of cartit articular cartilage
  • Compact bone on the outside but central region contain spongy or cancellous bone
• Periosteum


  The dense, white, fibrous outer covering of the bone, there is no periosteum at the joints, where bone is covered with Articular cartilage
• Bone


  A connective tissue consisting of cells separated from each other by large amounts of non-cellibus material called Matrix, with inorganic salts of calcium and phosphate deposited in matrix to increase its rigidity and strength
• Compact bone


  • Consists of Many similar units called osteoro or haversian sypres that run parallel to the long axis of the bone, giving the bone its Hanimam strength
  • Each osteon has a central canal (Haversian canal) surrounded by concentric layers of bony Matrix called lamellae
  • Lacunae are small spaces in the Matrix between the lamellae containing bone cells (osteacyle)
  • Canalidi are canals running between the lacunae allowing cells to pass from cell to cell
  • Contains at least one blood capillary, and possibly nerves and lymph capillaries in central canal of each osteon
• Spongy bone


  • Consists of irregular arrangement of thin, bany plates called trabeculae, with bone cells occupying spaces in the trabeculae, and nerves and blood vessels passing through imeguras spaces in the Matrix
• Cartilage


  Also a connective tissue, contains many fibres made of a protein called collagen embedded in a firm matrix of protein-carbohydrate complex called chondrit, allowing it to function as structival support with a certain amount of flexibility, found on the surface of bones at joints, trachea, bronchi, nose, larynx and outer ear
• Cartilage


  • Has a firm Matrix in which collagen fibres are added, with spaces containing cartilage cells called chondroblasts that produce Matrix and become surrounded by it
• Types of Joints


  • Fibourous / Fixed Joints
  • Cartilaginar/slightly Movable Joints
  • Synovial /Freely Movable Joints
• Fibourous / Fixed Joints


  • No Movement accours between the bones concerned
  • Bones are held in place by fibrous connective tissue
• Cartilaginar/slightly Movable Joints


  • Held in place by cartilage which allows slight Movement
  • Examples: pubic symphnas, joints between or adjacent vertebrae, joints between the ribs and sternum
• Synovial /Freely Movable Joints


  • Freely movable with the amount of Movement limited by ligaments, Muscles, tendom and adjoining bones
  • Categorised by type of Movement that occurs between articulating surfaces of bones
• Types of Synovial Joints

  • Ball and socket Joint
  • Hinge Joints
  • Pivot Joints
  • Gliding joints
  • Saddle Joints
  • Condyloid Joints
• Ball and socket Joint


  • Form when spherical head of one bone fits into a cup like cavity of another
• Hinge Joints


  • Allow movement in one plane only, like a hinged door
  • Form when convex surface of one bone fits into the concave of another
• Pivot Joints


  • Form when rounded, pointed or conical end of one bone articulates with a ring, formed partly by bone and partly by ligament
• Gliding joints


  • Allow movement in any direction in a plane, back and forth motion restricted by ligaments
• Saddle Joints


  • Where the bones forming the Joint are both saddle shaped, concave in one direction and convex to another
• Condyloid Joints


  • One surface of bone slightly convex, fits into depression in another bone
• Bone Modelling


  A continuous process of formation and building by osteoblasts and removal and clearing by osteoclasts, that gives bone its mature structure and maintains normal calcium levels in the body
• Osteoblast


  Cell that builds bones
• Osteoclast


  Cell that removes bones
• Osteocyte


  Longest living bone cell, make up 95% of cells in bone tissue
• Osteocyte


  Form when osteoblasts become buried in the mineral matrix of bone
• Osteoid


  Non-mineral, organic part of bone matrix, made of collagen and non-collagenous proteins
• Bone Matrix


  Part of bone tissue, forms bulk of mass of bone, comprising organic and inorganic substances
• Skeletal system

  
• Appendicular skeleton

  
• Types of bones

  
• Structure of bone and cartilage