Lobsters Are Osmoregulators

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  • Topic: American lobster, Hydrogen, Homarus
  • Pages : 4 (1315 words )
  • Download(s) : 1281
  • Published : February 6, 2006
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Methods

To determine the principals of osmoregulation, we sampled two lobsters from each tank and there were three different tanks which the water ranged in salinity. The experiment is to determine whether the six lobsters tested are osmoregulators or osmoconformers, this is done by obtaining a sample of hemolymph. The first step of the lab is to prepare the needle and syringe that will be taking the hemolymph. The syringe size was 1 ml, and the intention is to collect between 0.5 and 1.0 ml of hemolymph. The needle size was 20 gauge, because anything smaller would destroy the hemolymph cells. Then the lobster was picked up with a firm grim around the dorsal celphao-thorax region and flipped over to expose the ventral side. The hemolymph was be extracted from the central midline of the ventral pre-branchial region, of the first section. Although, before piercing the membrane, the bevel of the needle had to be pointing up. When the needle was injected into the membrane, it did not have to go any deeper than 2-3 mm into the hemocyannin (blood cavity). If the needle went to deep it would strike nerves of the lobster. This procedure was completed six times on six different lobsters, to determine if the lobsters are osmoregulators or osmoconformers. As soon as the hemolymph was taken form the lobster it was placed into a marked 1.5 ml microcentrifuge tube, and placed on ice. It was then taken to a lab and spun for 3 minutes on a microcentrifuge. The serum from the microcentrifuged hemolymph was taken back to the General Physiology Lab in Duffy and placed into osmometer, which measures the osmolarity. This is done by freezing the sample of hemolymph and the time that it takes to defrost depicts the amount of osmoles. Water analyses for the three tanks determined the temperature ºC, pH, salinity (ppt), oxygen levels and the ammonia content. The temperatures of all three tanks were taken by a digital thermometer and the pH of the water was taken by a pH...
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