20.2 Animal Structure and Functions

• Tissues 


  • Consist of one or more cell types
  • Allow them to collectively perform a specific task.
• Four types of tissues

  • Epithelial Tissues
  • Connective Tissues
  • Epithelial Tissues
  • Connective Tissues
  • Nervous Tissues
• Organ

  • A structural unit of two or more tissues organized in a specific way.
  • capable of carrying out specific tasks.
• Organ System


  • Two or more organs and other components interact physically, chemically, or both in a a common task.
  • Contributes to homeostasis.
• Homeostasis


  • Process of maintaning conditions inside the body within the range that body cell requires.
• Body Fluids


  • Animals consist mainly of water
  • 60% percent of body weight
• Intracellular Fluid


  • Fluid portion of the cytoplasm
• Extracellular Fluid(14 liters)

  • Fluid outside of cells,
  • Provides cells with the substance they need to stay alive
  • Carries away cellular wastes.
  • Interstitial Fluid (10.5 Liters) fluid in spoaces between body cells( Brain)
  • Plasma ( 3 Liters) Fluid portion of the blood
• Evolution of animal body plans


  • Both anatomical and physiological traits are genetically determined and vary among individuals.
  • Faces can only move into and out of an animals body by diffusing across a moist surface.
  • The evolution of lungs allowed vertebrates to maintain a moist respiratory surface inside their body.
  • Evolution modifies existing structures, it does not always produce the optimal body plan.