BIO 203- Liver 4 PDF

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Evaluate 1. The following statement is similar to those you might see on exams. Write a paragraph of 3-5 sentences describing 1) whether the statement is correct or incorrect and 2) the reasoning for your answer. Your answer should demonstrate your understanding of the physiological concepts underlying the statement and be written professionally. At a chemical synapse, the release of neurotransmitter occurs in response to a graded depolarization of the synaptic terminal. This statement is correct. The release of neurotransmitters are caused by action potentials reaching the synaptic terminal. The action potential travels along the axon until it reaches the synaptic terminal, then the synaptic vesicle is provoked which releases its neurotransmitters. Unlike graded potentials which can either hyperpolarize and depolarize, action potentials can only depolarize. 2. Write a paragraph of 3-5 sentences answering the following questions. Your response should first answer the question and then go onto state physiological interpretation behind your answer. Paragraphs that demonstrate complete and thorough reasoning will receive full points. You discover a drug that prevents voltage-gated Na+ channel inactivation gates from opening when they are closed but has no effect on inactivation gates when they are open. What would happen to the action potential in a neuron exposed to this drug? Explain your answer. Assume the neuron is at resting membrane potential (e.g., -70 mV) at the time it is exposed to the drug. At resting membrane potential, some of the Na+ channels will already be open and allowing sodium to move into the cell. This would normally trigger other Na+ channels to open and make the membrane potential rise very rapidly. This can’t happen because the channels that are closed are stuck closed, so the membrane potential will rise very slowly. Normally this event would be considered hyperpolarization, but with the Na+ channels being closed, it would still be polarizing, but not at the level of hyperpolarization. An action potential is caused by a rapid increase or decrease in the membrane potential, so an action potential would not occur in this case....