Summary biology unit 5: Support and locomotion

5.1 The human skeleton

  • Endoskeletons are skeletons inside the body
  • Human skeleton has 206 bones
  • The head bones belong to the skull
  • The skull is supported by the backbone
  • Rib cage:
    • Thoracic vertebrae
    • Ribs
    • Breast bone
    • Pectoral girdle:
      • Shoulder blades
      • Collar bones
      • Pelvic girdle
        • Pelvis (attached to backbone
        • Limbs:
          • Arms
          • Legs
          • Skull has fused joints
          • The skull of a baby is not completely joined. These are called fontanelles
          • At the age of 2 the fontanelles close.                                                                                     
          • Functions of a skeleton:
            • Support
            • Movement
              • Muscles are attached to the bones
              • Most of the bones are in such a position that they allow movement
  • Protection
  • Shape
  •  

5.2: The skeletons of mammals

  • Plantigrades: walk on the whole sole of his feet when he walks. E.g.
    • Bears
    • Humans
    • Digitigrades: walk on their toes when he walks. E.g.
      • Cats
      • Dogs
      • Unguligrades: walk on the tip of their toes. E.g.
        • Horses
        • Cows

5.3 Bone and cartilage

  • Your body is supported by two different types of tissue:
    • Bone tissue
    • Cartilage tissue
    • Both contain extracellular material between the cells
    • Cartilage tissue is composed of cells clustered inside the extracellular material
    • It’s constructed in such a way that it’s strong and flexible
    • Where can cartilage be found? (adults)
      • Ears
      • Nose
      • Between the vertebrae
      • In joints
      • Bone tissue is composed of cells surrounding tiny canals. These canals contain blood vessels
      • The extracellular material is much tougher than that of cartilage tissue
      • The extracellular material in bone tissue is composed of:
        • Calcium phosphate
          • Strong and rigid
          • Disappears in hydrochloric acid
  • Collagen
    • Flexible
    • Disappears in a flame
    • This makes it hard without being brittle
    • Collagen is replaced by calcium phosphate as we grow older

 

5.4 Joints

  • A place where two bones meet is called a joint. Muscles on either side make movement possible
  • We have four types of joints:
    • Fused joints
      • Immovable
      • E.g. sacrum, coccyx
  • Sutures
    • Immovable
    • E.g skull
  • Cartilaginous joint
    • Able to move slightly
    • Also function as shock absorbers
    • E.g. vertebrae
    • E.g. ribs
  • Synovial joint
    • moveable
    • most common
    • found mainly in limbs
    • e.g. phalanges
    • we have three types of synovial joints:
      • ball-and-socket joint
        • e.g. shoulder joint
        • can move in all directions
        • hinge joint
          • e.g. between two phalanges
          • can move in one direction
          • pivot joint
            • e.g. between ulna and radius
            • a bone rotates around another
            • The end of a bone is covered by a slippery layer of cartilage. This provides a smooth surface for easy gliding and it prevents the bones wearing away. It also acts like a shock absorber
            • The synovial membrane produces an oily liquid called synovial fluid, which makes movement easy
            • The bones are held together by the synovial membrane
            • Ligaments often stretch across the joints to connect different bones

5.5 Muscles

  • Muscles make your body move by pulling on the bones
  • The muscular system is composed of around 650 muscles
  • Muscles are attached to bones by fibres called tendons
  • The site where a tendon is attached to the bone is called an attachment site
  • Muscles are able to contract, tendons aren’t
  • When a muscle contract, it gets shorter and thicker. When it shortens, it pulls on what it is attached to. This is how movement occurs
  • When a muscle is on its rest, it’s long and thin
  • Antagonistic muscles are muscles that have to work in opposite ways
    • You have a flexor and an extensor muscle. E.g. flexor: biceps, extensor: triceps
    • The biceps contract to bend the arm
    • Muscles can only push, they cannot push. Therefore, they have to work in pairs
    • When you want to straighten your arm, you need the triceps (extensor muscle) must contract and the biceps will relax to let this happen

5.6 Posture and movement

  • Some people have a bad posture. This can cause backache
  • The backbone has a double S form
  • This form is supported by the muscles of the backbone which are connected to the vertebrae
  • The discs of cartilage between the vertebrae are called intervertebral discs
  • They’re shock absorbers
  • If you have bad posture and repeatedly hold yourself in the wrong position, the backbone can get in the wrong position
  • Because of that one side of the backbone gets overloaded. Some muscles have to work harder because of this overload. The intervertebral discs also become overloaded
  • In time they can lose their flexibility
  • The correct way to sit straight up is:
    • With an angle of 90° between the fibula and the thighbone
    • If you put your arm on the table there must be an angle of 90° with your upper body
    • When you lift (heavy) things your backbone should be in the double S form as well
    • Regular physical exercise is good for your health
    • It’ll improve your fitness
    • With untrained muscles the risk of an injury is bigger than when your muscles are trained

5.6 Posture and movement

  • Some people have a bad posture. This can cause backache
  • The backbone has a double S form
  • This form is supported by the muscles of the backbone which are connected to the vertebrae
  • The discs of cartilage between the vertebrae are called intervertebral discs
  • They’re shock absorbers
  • If you have bad posture and repeatedly hold yourself in the wrong position, the backbone can get in the wrong position
  • Because of that one side of the backbone gets overloaded. Some muscles have to work harder because of this overload. The intervertebral discs also become overloaded
  • In time they can lose their flexibility
  • The correct way to sit straight up is:
    • With an angle of 90° between the fibula and the thighbone
    • If you put your arm on the table there must be an angle of 90° with your upper body
    • When you lift (heavy) things your backbone should be in the double S form as well
    • Regular physical exercise is good for your health
    • It’ll improve your fitness
    • With untrained muscles the risk of an injury is bigger than when your muscles are trained

 

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E.

E.

Thnx, helpt heel erg met leren👍

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J.

J.

deze dude die dit heeft geupload is echt baas

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