Act 16: Invertebrates Gas Exchange and Internal Transport

• Tracheal system - does not need circulatory system, invaginated, composed of branching tubes that deliver oxygen to the tissues.
• Spiracles - entry/exit point of gas
• Spiracles - cavity in the sides of segment
• Each segment the spiracles are paired.
• Trachea - system of branched elastic air tubes
• Thorax has 3 segments and 2 pairs of spiracles
• Abdomen has 8 segments and 8 pairs of spiracles
• Cockroach have tagmata segmentation.
• Taenidia - supporting layer to avoid collapsing due to air pressure
• Tracheoles - finer rebranching of tubes
• Respiratory Passageway Diagram:

  O2 - spiracles - trachea - tracheoles - cells - CO2 - tracheoles - trachea - spiracles - environment
• Plastron - series of hair in surface of body that trap oxygen in the form of air bubble.
• Siphon - tubular organ for breathing (usually in aquatic insects like mosquito wriggler)
• Water bugs - keep their abdomen above the surface of water for air intake.
• Tracheal system - respiratory system of insects
• Book lung - attached to circulatory system
• Book lung - for arachrids
• Book lung - leaf stacked
• Hemolymph - hemoglobin free blood
• Hemocyanin - like RBC transport waste CO2 t areas where it can diffuse out in the atmosphere.
• Two types of circulatory system in invertebrates: open type and closed type
• Open type - absence of blood vessels ; hemolymph by a heart into the body cavities called hemocoels or sinuses.
• Open type - tissue bathed by the hemolymph
• Open type - direct to organ
• Closed type - repeating cycle
• Heart of cockroach is found dorsally.
• Heart of cockroach encompasses thorax to abdomen.
• Heart of cockroach has 13 chambers.
• Aorta - biggest chamber.
• Alary muscle - for contraction and relaxation
• Ostium - cavity entry point of nutrients in each chamber.
• Heart of cockroach has no backflow; from lower chamber to aorta to organs.
• Circulatory Passageway Diagram in Cockroach (Open Type):

  alary muscle relax - hemolymph enters ostia - alary muscle contracts - hemolymph pass into cavity - hemolymph bathes organ
• Closed type - earthworm
• Closed type - circulates blood exclusively in blood vessels.
• 3 main blood vessels within earthworm: aortic arches, dorsal blood vessels, ventral blood vessel.
• Aortic arches - pumps blood into dorsal and ventral blood vessels.
• Dorsal blood vessels - responsible for carrying blood to the front of the earthworm's body
• Ventral blood vessel - carrying blood to the back of earthworm's body.
• Dorsal aorta - aortic arches - ventral aorta