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Crayfish lab

Date post: 21-Jun-2015
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Crayfish lab
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  • 1. Quantifying the hemolymph glucoseconcentration response in crayfish

2. Comparative BiologyWhy is it so important?Comparing features (physiology, behavior, etc.)across different species experiencing similar situations,helps us to hypothesize trends in how organisms respond to theirenvironment! 3. Physiology comparisonsMost invertebrates Most vertebratesCirculatory system:similar (blood transports nutrients)but different (open vs. closed) 4. How do we control our behaviors andenergy use?Endocrine System Central Nervous System 5. Glucose: its how cells get energy Cellular respiration Aerobic (needsoxygen) Anaerobic (nooxygen available) Glucose is requiredfor both! When our musclesrun out of oxygen,they switch toanaerobic (muchless efficient!) Waste product: lacticacid 6. Glucoseregulation Hyperglycemic(too much glucose)Hypoglycemic (not enoughglucose) 7. Crayfish produce Crustacean Hyperglycemic Hormone(CHH) from the sinus glands behind their eyes!This hormone is similarto glucagon in humansit tells the crayfishsbodyto release more CHHglucoseinto the hemolymph! 8. Temperature affectsblood-glucose levelsEndotherms (mammals,birds) and Ectotherms(reptiles, fish, arthropods,crustaceans) both need tomaintain proper blood-glucoselevels at differenttemperatures (rememberhomeostasis?) 9. Salinity affects blood-glucose levelsSubstancesabsorbed/ingestedfrom theenvironment (food,air, water) canaffect your bodysrelease ofhormones such ascortisol (stresshormone), whichcan in turnstimulate otherhormones,including insulinand glucagon,which can affectyour blood- 10. Stress affects blood-glucoselevels Stress (searching formates, fighting forterritory, avoidingpredators, etc.) canelevate blood-glucoselevels Fight-or-flight response:Your body releasesmany hormones,including glucagon,which provides yourcells with more glucose,so you have moreenergy to deal with atough situation! 11. For lab today We want to quantify how different conditions induce changes incrayfish hemolymph glucose concentration. Obtain crayfish, take hemolymph sample, apply treatment, takehemolymph sample again Compare before-treatment to after-treatment: is there a changein glucose concentration?PLEASE BE CAREFUL WITH YOUR SYRINGES AND NEEDLES,as well as the crayfish clawsIf you have ANY QUESTIONS, please ASK your TA 12. Insert needle under the back of the carapace (1)Insertneedle atthis angle


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