Biology B5

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Skeletons

Types of Skeletons

  • An internal skelton has many advantages:
  • Provides and internal framework for the body
  • Grows with the rest of the body
  • It is flexible due to the many joints
  • Allows easy attatchment of muscles

Cartilage and Bone

  • Cartilage and bone are living tissues which contain living cells
  • A long bone is a long shaft containing bone marrow with blood vessles. There is a head covered with cartilage at each end
  • Long bones are hollow, so they are stronger and lighter than solid bones
  • The living tissues can be infected by bacteria and viruses
  • They are able to grow and repair themselves
  • In the early stages, the skelton is made of cartilage. During ossification, the cartilage is replaced by bone.
  • If cartilage remains between the head and shaft, the bone and person is still growing
  • Bones can be easily broken by a sharp knock
  • Elderly people's bones lack calcium and phosphorous, resulting in osteoporosis, making them prone to fractures
  • In an accident it is dangerous to move someone with a suspected fracture
  • Broken vertebrae in the backbone can damage the spinal cord, resulting in paralysis or death

Joints

  • Synovial joints (ball and socket/hinge) contain synovial fluid, a synovial membrane, ligaments and cartilage
  • A ball and socket joint has more movement than a hinge joint, which is restricted to an up-and-down movement
  • The forearm is raised and lowered by atagonistic muscles, biceps and triceps
  • The synovial fluid acts as a cushion against shock and a lubricant for easy movement
  • The synovial membrane holds in synovial fluid
  • Cartilage prtects the bone head
  • Ligaments hold bones in place

Circulatory Systems / Cardiac Cycle

Ciculatory Systems

  • Animals need a blood circulatory system to ensure their cells recieve enough food and oxygen in order to remove waste products (CO2)
  • As blood flows through arteries, veins and capillaries, blood pressure decreases
  • Veins have valves to stop backward blood flow
  • High blood pressure can damage the fragile walls of the capillaries
  • Single circulatory system: heart, gills, body
  • Double circulatory system: heart and lungs (obtain oxygen), heart and body (deliver oxygen to body cells)
  • Double circulatory system = four-chambered heart : two atria to receive blood, two

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