KINESIOL 2Y03 Lecture Notes - Lecture 9: Resting Potential, Depolarization, Repolarization

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parveendhillon73

7 Nov 2022

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Neurons are electrically excitable due to resting membrane potential. To create an electrical signal need to change membrane potential (cid:8869) done with gated ion channels. Action potentials: allow communication over short + long distances. 4)ligand andmechanically (cid:8869) voltage pated ion channels gated ion channels. Potentials can be addedtogether to become larger in pmplitude. Large enough graded potential may cause membrane to reach threshold. Spreads over surface of cell w/o dying out (cid:8869) not local! Resting membrane potential inactivation gate of sodium channel is open and. Voltage gated kt channel is closed activation gate is closed (not can"t get in. Graded potential reaches threshold voltage - gated nat channels open. End of repolarizing phase:- lt outflow returns membrane potential back to 70 m/ Nat activation gate closes, inactivation pate reopens. Afterpotential:- if enough it leaves cell, causes hyperpolarization. Return to resting membrane potential: - it channels close. Nat/kt pump brings resting potential back to -forv.

Related Questions

In order for Neurons to communicate, Resting Membrane Potential must CHANGE. Examples of changes in Membrane Potential included Graded Potentials and Action Potentials. In order for there to be a change in membrane potential, ions must move across the plasma membrane. There are THREE Primary types of Ion Channels: Passive (Leak) Channels, Voltage-gated Channels and Chemically-gated Channels.

DIRECTIONS

Select ONE type of Ion Channel and indicate whether that Ion Channel is MOST important for producing Resting Membrane Potential, Graded Potentials or Action Potentials. Provide detailed support for your choice.

purpleweasel693

DIRECTIONS

Indicate which voltage-gated channels are functioning during each phase of an Action Potential

skyhorse437

This is the peak depolarization in an action potential. At this point in an action potential two events start to happen.

1. Na+ channels begin to inactivate, which is equivalent to closing.

2. A majority of the K+ channels are beginning to open.

Determine what happens to the membrane potential when voltage-gated K+ channels are open simultaneously with voltage-gated Na+ channels (and the leak K+ channels which are still open). Increase the membrane permeability to K+ by increasing it to 115.

i. What happens to the membrane potential Em? __________________________

j. Why does the membrane potential change in this direction? __________________________ Now inactivate the voltage-gated Na+ channels by reducing the membrane permeability for Na+ back to 1. k. What is the new membrane potential? _____________

l. Is the new membrane potential less negative or more negative than the resting membrane potential listed in line âbâ of this section? _____________

m. Why? (hint: what 2 types of K+ channels are open now?) n. Under the current ionic concentrations given, what is the most negative value that the membrane potential could reach? _____________ (Increase the permeability of the membrane to K+ to confirm your answer.)

o. What equilibrium potential has the same value? _____________

p. At this point in the action potential, when the membrane potential is more negative than the resting potential, the membrane potential is said to be hyperpolarized. What happens to voltage-gated K+ channels (membrane permeability to K+) to bring the membrane potential back to its resting potential near -70mV?_____________

When the membrane potential became more negative than the Threshold potential, the inactivated voltage-gated Na+ channels became reactivated. After the voltage-gated K+ channels closed to enable the membrane potential to return to resting membrane potential they became ready to open again. Both channels are ready to open again in order to fire another action potentia

sapphirepanda54

KINESIOL 2Y03 Lecture Notes - Lecture 9: Resting Potential, Depolarization, Repolarization

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