mapua institute of technology, physics 3 lab report for first experimentFull description
Full description
Full description
physio pptFull description
Physiology
Full description
samplex on physio
Summary of Renal Physiology.
uworld
uworld
PhysioFull description
Descripción completa
Name: Edward Tyler Exercise 3: Neurophysiology of Nerve Impulses: Activity 1: The Resting Membrane Potential Lab Report Pre-lab Quiz Results You scored 100% by answering 4 out of 4 questions correctly. 1. What is the approximate concentration of K+ inside a typical cell (intracellular concentration)? concentration)? You correctly answered: a. 150 m M 2. What is the approximate concentration of K+ outside a cell (extracellular concentration)? You correctly answered: b. 5 m M 3. What is the approximate approximate concentration concentration of Na+ inside a cell (intracellular (intracellular concentration)? concentration)? You correctly answered: b. 5 m M 4. What is the approximate concentration of Na+ outside a cell (extracellular concentration)? You correctly answered: a. 150 m M
03/12/15
page 1
Experiment Results Predict Question: Predict Question: Predict what will happen to the resting resting membrane potential if the extracellular K+ concentration is increased. Your answer : a. The resting membrane potential will become more negative. Stop & Think Questions: What is the polarity of the resting membrane potential (voltage)? You correctly answered: b. negative What does it mean that the voltage just inside the membrane is negative? You correctly answered: b. There are more negative charges than positive charges just inside insi de the membrane. The membrane of most cells, including neurons, contains passive, open, K+ leak channels. Given the normal K+ concentrations and the resultant concentration gradient, which direction would K+ be expected to move (diffuse) through these leak channels? You correctly answered: b. out of the cell What effect does does increasing extracellular K+ have on the net diffusion of K+ out of the cell? You correctly answered: b. It decreases the net diffusion of K+ . Which way would Na+ move across the membrane if there were open Na+ channels? You correctly answered: a. Na+ would diffuse into the cell. The membrane has open K+ channels, and changing extracellular extracellular K+ concentration results in a change in membrane membrane potential. Changing the extracellular Na+ concentration does not significantly change the membrane potential. What do your results suggest about the number or state (open or closed) of Na+ channels in the resting membrane of a neuron? You correctly answered: b. Na+ channels are mostly closed. Experiment Data: Extracellular Fluid (ECF) Control Control Control Control High K+ High K+ High K+ High K+ Low Na+ Low Na+ Low Na+ Low Na+
Microelectrode Position Cell body extracellular Cell body intracellular Axon extracellular Axon intracellular Axon intracellular Axon extracellular Cell body extracellular Cell body intracellular Cell body intracellular Cell body extracellular Axon extracellular Axon intracellular
Post-lab Quiz Results You scored 100% by answering 3 out of 3 questions correctly. 1. A negative membrane membrane potential was recorded when the tip tip of the microelectrode was You correctly answered: d. both inside the cell body and inside the axon. 2. Which of the following caused a change in membrane potential from -70 to to -40 in the cell body? You correctly answered: a. an increase in extracellular K+ 3. Which of the following has the most negative negative voltage? You correctly answered: c. between the inside of the axon and the outside of the axon with control K+ ECF
03/12/15
page 7
Review Sheet Results 1. Explain why increasing extracellular extracellular K+ reduces the the net diffusion of K+ out of the neuron through through the K+ leak channels. Your answer: Because the amount of potassium keeps more K+ from leaving the cell gradient of potassium is higher outside the cell 2. Explain why increasing extracellular K+ causes the membrane potential potential to change to a less negative value. How well did the results compare with your prediction? Your answer: The more K+ outside the more negative it is on the inside of the cell 3. Explain why a change in extracellular extracellular Na+ did not significantly alter the membrane potential in the resting neuron? Your answer: Because at restng state the Na+ gate arent open 4. Discuss the relative permeability permeability of the membrane membrane to to Na+ and K+ in a resting neuron. Your answer: At rest permeability is the same 5. Discuss how a change in Na+ or K+ conductance would affect the resting resting membrane membrane potential. potential. Your answer: Both are positively charged so when they move in and out of the cell the charge changes
