1' Stability, support and movement

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1. Stability, support and movement

• 1.1 Bones, muscles and joints
• Functions of skeleton
• support the body and keep it in shape
• for muscle attachment and act as a level system
  for movement and locomotion -- muscles are
  attached to bones through ligaments and tendons
  to form a level system which can keep the body in
  shape and produce movement and locomotion through
  contraction and relaxation of muscles
• protect the internal organs -- e.g. skull
  protects the brain thoracic cage protects lung
  and heart
• produce red blood cells -- red bone mallow in
  soft bonds produces RBCs

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Structure of joints

• Joints can be classified as immovable and movable
  joints.
• immovable between bones of skull and pelvic
  girdle
• Movable hinge joints (e.g. elbow, knee and
  finger joints) and ball and socket joints (e.g.
  shoulder and hip joints)

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• The surface of joints is covered with cartilage
  which contains pores. Synovial fluid is secreted
  from synovial membrane for reducing friction and
  absorbing shock.
• Joint is surrounded by strong fibrous capsule
  which helps holding the bones of the joint in
  position.

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• 1.2 Support in animals
• Hydrostatic skeleton
• Exoskeleton
• Endoskeleton

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• Hydrostatic skeleton
• Fluid is secreted within the body and enclosed by
  body wall muscles.
• Muscles are not attached to any structures and
  thus they can only pull against each other
• The combined effect of muscle contraction and
  fluid pressure serves to maintain the shape and
  form of the animal.
• Longitudinal and circular muscles act
  antagonistically against each other to bring
  about locomotion.
• Example earthworm

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• Exoskeleton
• Epidermal cells secrete a non-cellular cuticle,
  composed mainly of chitin. It acts as a hard
  outer covering to the animal and is made up of a
  series of articulated plates or tubes covering or
  surrounding organs.
• The combination of a system of plates and tubes
  joined together by flexible membranes provides
  both protection and mobility.
• Example arthropods

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• Endoskeleton
• Made either of cartilage or bone, is located
  within the organism and is internal to the
  muscles.
• It is composed of living tissue and so can grow
  steadily within the animal
• Joints and elastic ligaments exist to allow
  movement and maintain the correct relative
  position
• Examples human, dog

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• 1.3 Locomotion in animals

Amoeboid movement
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Paramecium
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Earthworm
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• Insect

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• Fish

Bird Tetrapedal mammals