insect

• Insects have an exoskeleton which is made of?

  Hard fibrous material.
• What is the function of the exoskeleton?

  For protection and a lipid layer to prevent water loss.
• Instead of lungs, what do insects have?

  A tracheal system.
• What are the adaptations that insects have to prevent water loss?

  1.Insects have a small surface area to volume ration where water can evaporate from. 2.Insects have a waterproof exoskeleton. 3.Spiracles, where gases enter and water can evaporate from, can open and close to reduce water loss.
• What is involved in the tracheal system?

  Trachea, tracheoles and spiracles.
• What is the structure of spiracles?

  They are round, valve like openings, running along the length of the abdomen.
• What happens at the spiracles?

  Oxygen and carbon dioxide enter and leave via the spiracles.
• What is attached to the spiracle openings?

  The trachea
• The trachea is network of what?

  Internal tubes.
• The trachea tubes have what within them and why?

  The trachea tubes have cartilage rings within them to provide structural support and prevent collapse.
• The trachea branch into smaller tubes, deeper into the abdomen of the insect called what?

  Tracheoles
• What is the function of the tracheoles?

  They extend throughout all the tissues in the insect to deliver oxygen to all respiring cells.
• What is the first method of moving gases in the tracheal system?

  gas can exchange by diffusion, as when cells respire , they use up oxygen and produce carbon dioxide, creating a concentration gradient from the tracheoles to the atmosphere.
• What is the second method of moving gases in the tracheal system?

  Is mass transport, in which an insect contracts and relaxes their abdominal muscles to move gases on mass.
• What is third way of moving gases in the tracheal system?

  When an insect is flying, the muscle cells start to respire anaerobically to produce lactate. This lowers the water potential of the cells and the water will move from the tracheoles into the cells by osmosis. This decreases the volume of gas in the tracheoles and as a result more air from the atmosphere is drawn in.
• What adaptations do insects have for efficient diffusion?

  1.Large number of fine tracheoles-large surface area. 2.Walls of tracheoles are thin and short distance between spiracles and tracheoles-short diffusion pathway. 3.Use of oxygen and production of carbon dioxide sets up steep diffusion gradient. 4. trachea provide tubes full of air so fast diffusion into insect's tissues