PhysioEx Exercise 3 Activity 1.htm - Sections Menu PEx The Resting Membrane Potential Reset Activity Objectives Introduction Pre-lab Quiz Experiment

PhysioEx Exercise 3 Activity 1.htm - Sections Menu PEx The...

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Sections Menu PEx The Resting Membrane Potential Reset Activity
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Objectives Introduction Pre-lab Quiz Experiment Post-lab Quiz Review Sheet Lab Report Accessibility Objectives Introduction Pre-lab Quiz Experiment Post-lab Quiz Review Sheet Lab Report Pre-lab Quiz Results You scored 100% by answering 4 out of 4 questions correctly.
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1 What is the approximate concentration of K + potassium superscript plus inside a typical cell (intracellular concentration)? You correctly answered: 150 mM. 2 What is the approximate concentration of K + potassium superscript plus outside a cell (extracellular concentration)? You correctly answered: 5 mM. 3 What is the approximate concentration of Na + sodium superscript plus inside a cell (intracellular concentration)? You correctly answered: 5 mM. 4 What is the approximate concentration of Na + sodium superscript plus outside a cell (extracellular concentration)? You correctly answered: 150 mM. Experiment Results Predict Question 1 Predict Question: Predict what will happen to the resting membrane potential if the extracellular K + potassium superscript plus concentration is increased. Your answer: The resting membrane potential will become less negative. Stop & Think Questions 1 What is the polarity of the resting membrane potential (voltage)? You correctly answered: negative. 2 What does it mean that the voltage just inside the membrane is negative? You correctly answered: There are more negative charges than positive charges just inside the membrane.
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3 The membrane of most cells, including neurons, contains passive, open, K + potassium superscript plus leak channels. Given the normal K + potassium superscript plus concentrations and the resultant concentration gradient, which direction would K + potassium superscript plus be expected to move (diffuse) through these leak channels? You correctly answered: out of the cell . 4 What effect does increasing extracellular K + potassium superscript plus have on the net diffusion of K + potassium superscript plus out of the cell? You correctly answered: It decreases the net diffusion of potassium superscript plusK + . 5 Which way would Na + sodium superscript plus move across the membrane if there were open Na + sodium superscript plus channels? You correctly answered: sodium superscript plusNa + would diffuse into the cell. 6 The membrane has open K + potassium superscript plus channels, and changing extracellular K + potassium superscript plus concentration results in a change in membrane potential. Changing the extracellular Na + sodium superscript plus concentration does not significantly change the membrane potential. What do your results suggest about the number or state (open or closed) of Na + sodium superscript plus channels in the resting membrane of a neuron?
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