Gas Exchange in Incects

• How do insects reduce water loss from their gas exchange system?

  By closing their spiracles
• What have some insects evolved to increase?

  Rate of gas exchange
• What is the surface area to volume ratio in unicellular organisms?

  Large surface area to volume ratio
• Why do larger organisms require specialized gas exchange organs?

  Because they have a small surface area to volume ratio
• What specialized gas exchange organ do mammals have?

  Lungs
• What does blood do in mammals regarding oxygen?

  Transports oxygen around the body
• What is the primary function of the gas exchange system in insects?

  To provide oxygen directly to cells
• What is the protective covering of insects made of?

  Polysaccharide chitin
• What are the small openings on the exoskeleton called?

  Spiracles
• What do spiracles allow to diffuse into the insect's body?

  Oxygen and carbon dioxide
• What prevents the trachea from collapsing?

  Spirals of chitin
• What are the very fine tubes extending from the trachea called?

  Tracheoles
• Why do tracheoles allow rapid diffusion of oxygen?

  They have a short diffusion distance
• What gas is produced during aerobic respiration?

  Carbon dioxide
• How does carbon dioxide diffuse back into the air?

  From high concentration in tracheals
• What happens to tracheal fluid during intense activity?

  Water moves into the cells
• What does the reduction of tracheal fluid volume allow?

  More surface for gas diffusion
• How does diffusion occur in insects' gas exchange?

  It is a passive process
• Why are insects generally small?

  To reduce diffusion distances
• What can diffuse out of an insect via spiracles?

  Water vapor
• What surrounds each spiracle to reduce water loss?

  Muscular sphincter
• What can some insects do to change the volume of their thorax and abdomen?

  Contract muscles
• What is the bulk movement of air in insects called?

  Mass transport
• What do air sacs in some insects do?

  Store air for gas exchange
• When can insects use oxygen in air sacs?

  When spiracles are closed
• What are the key components of the gas exchange system in insects?

  • Spiracles for gas entry
  • Trachea for gas transport
  • Tracheoles for gas diffusion
  • Tracheal fluid for moisture
• What are the advantages of the insect gas exchange system?

  • Direct oxygen delivery to cells
  • Large surface area for gas exchange
  • Short diffusion distances
  • Ability to reduce water loss