Excretory and Skeletal System

• Excreation is any process that gets rid of unwanted waste from the body
• Main organs involved in excreation are your skin, lungs, liver and kidney's.
• Excretory System


  The body system which excretes unwanted waste through the skin, lungs, liver and kidneys.
• Lungs in Excreation


  Excretes carbon dioxide
• Kidneys in excretion

  Excretes urea, water and other chemicals that are in excess
• Liver in Excretion


  Breaks down toxins for excretion
• Joints


  Where two bones meet. The bones are held together by ligaments. Cartilage is covered in synovial fluid at the end of the bones to stop them from scraping against eachother.
• Pivot Joint


  Allows for twisting movement. This type of joint is between the skull and the spine.
• Hinge joint


  Allow movement in only one axis, like your elbows and knees
• Ball and socket joints


  Joints that allows movement in many directions, like your hip and shoulder joints.
• Muscles


  They are connected to the bones with tendons. As they extend and contract, bones are moved around accordingly.
• Involuntary Muscles


  Muscles that a contract and relax automatically, such as the heart muscles.
• Voluntary Muscles

  Muscles that you choose to move. This is any movement of your body that you actually think about.
• Immovable joint


  Joints that do not move such as skull joints. Their benefit is that they provide soft tissue between bones, and absorb energy from big knocks.
• Bones on the inside


  Bones have several layers. On the inside, they have bone marrow (where white blood cells are made) and spongy tissue.
• Bones on the outside


  Bones have several layers. Protecting the soft insides is a hard covering made from calcium and phosphorus.
• Bones at the joints


  The ends are covered with cartilage and synovial fluid to prevent bones from grinding together.
• Ligaments


  Fiberous tissue that connects bones to bone
• Tendons


  Strong, flexible tissue that connects muscles to bones