PRACTICAL 7 -

  • PRE LAB -

    • dissections are essential to a complete understanding of internal biological functions, there are some ethical issues with dissection, including the way in which animals are raised and killed

  • EQIPMENT -

    • live locust

    • dead locust

    • forceps

    • cork board

    • dissecting pins

    • seeker

    • specimen jar or syringe

    • microscope slides and coverslips

    • methylene blue stain

    • dissecting microscope

    • hand lens

    • pipette

    • watch glass

  • RISK ASSESSMENT -

  • BIOHAZARD -

    • RISK - contamination

    • SAFETY PRECAUTION - use disinfectant, keep sample on dissection board and wash hands after with soap

    • EMERGENCY PROTOCOL - seek assistance

    • RISK LEVEL - low

  • DISINFECTANT -

    • RISK - flammable

    • SAFETY PRECAUTION - keep away from naked flames

    • EMERGENCY PROTOCOL - put out fire and seek assistance

    • RISK LEVEL - low

  • SHARP TOOLS -

    • RISK - cuts from sharp objects

    • SAFETY PRECAUTION - cut away from fingers, use forceps to hold sample and keep away from the edge of the desk

    • EMERGENCY PROTOCOL - elevate and apply pressure to cuts and seek medical assistance

    • RISK LEVEL - low

  • DISECTION TIPS -

    • wear a lab coat, gloves and goggles for all dissections

    • pin the locust to the dissection board and remove the exoskeleton so the internal gas exchange system can be observed

    • locusts have spiracles controlled by sphincters, trachea held open by chitin spirals and tracheoles where gas exchange occurs

    • when you dissect a locust you should flood the specimen with water so that the trachea show up as silvery-grey

    • when observing the live locust, watch for rhythmic movements of the abdomen, this is the locust mechanically ventilating its gas exchange system