Crayfish Cardiac Physiology University of North TexasBIOL 4510crayfish cardiac

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Crayfish Cardiac Physiology Introduction: The vertebrate heart and invertebrate heart share some similarities and differences. In most vertebrates, blood flows in a closed circulatory system. The h... eart of vertebrate is myogenic, each cell will beat without any neural input. In contrast, invertebrates including crustaceans, like crayfish which is what we used in this experience, blood flows in an open circulatory system. The invertebrate heart is neurogenic, which means the cell only beat with neural inputs from the cardiac ganglion. The heart of crayfish is in the dorsal portion of the cephalothorax which is right in front of the abdominal. The heart lays underneath a layer of hard shell which is easy to access. By placing fine wires through the shell on either side of the heart to create a low voltage electrical circuit, we can measure the heart rate of the crayfish because the impedance of this circuit will change as the heart beats. Crayfish is poikilotherms, which mean they can match their body temperature with the temperature of the environment they are in. If the temperature of their surrounding decrease, their body temperature also decreases, causing the enzymes to change, as the result, it affects the contraction of the heart, causes the heart rate to slow down. Both the hearts beat of vertebrate and invertebrate are modulated by neurotransmitters. In this lab we exanimated varies different neurotransmitters to determine the effective concentration of them on crayfish heart rate. The serotonin will speed up the heart rate of crayfish and has variable effect on vertebrate heart beats [Show More]

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