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Physioex 9.0 Exercise 3

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Physioex 9.0 Exercise 3

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  • March 2013
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Activity 1
1.Increasing extracellular K+ reduces the net diffusion of K+ out of the neuron through the K+ leak channels because the membrane is permeable to K+ ions. Therefore, the K+ ions will diffuse down its concentration gradient from a region of higher concentration to a region of lower concentration. 2.Increasing extracellular K+ causes the membrane potential to change to a less negative value because the K+ ions diffuse out across the membrane. My results went well compared to my prediction because I predicted that the resting membrane potential would become less negative. 3.The extracellular Na+ did not alter the membrane potential in the resting neuron because the Na+ channels were mostly closed. 4.Na+ and K+ both have a relative permeability of 0 voltage outside a resting neuron and a relative negative permeability inside a resting neuron. 5.A change in Na+ or K+ conductance would affect the resting membrane potential because if the membrane is permeable to a particular ion, that ion will diffuse down its concentration gradient from a region of higher concentration to a region of lower concentration. Activity 2

1.The passive channels that are likely found in the membrane of the olfactory receptor are chemical, in the membrane of the Pacinian corpuscle are pressure, and in the membrane of the free nerve ending are several different modalities because the sensory end of the nerve is less specialized. 2.The term graded potential is meant to describe the amplitude of the receptor when there is an increase in stimulus intensity with an appropriate stimulus. 3.The stimulus modality that induced the largest-amplitude receptor potential in the Pacinian corpuscle was pressure with high intensity. My results went well compared to my prediction because I predicted that high intensity pressure would induce the largest-amplitude receptor potential in the Pacinian corpuscle. 4.The stimulus modality that induced the largest-amplitude receptor potential in...