BIOL 2410 Lecture Notes - Lecture 12: Axon Hillock, Axon Terminal, Threshold Potential

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pucealligator102

7 Oct 2016

School

University of Manitoba

Department

Biological Sciences

Course

BIOL 2410

Professor

Diana Mlinar

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Document Summary

Neuron physiology iii - electrical signaling in the neuron. The neuronal plasma membrane is rich with ion channels that differ according to: Whether or not they are gated/how the gates are stimulated to change position. Many gates ion channels exists along the length of the neuronal plasma membrane. Different stimuli exists to open the gates, altering ion permeability and transmembrane potential. A critical change in the transmembrane potential causes the gate to open. When gated ion channels are stimulated to open, the membrane permeability for a given ion dramatically increases. Ions will ow according to their equilibrium potential. Occur in response to signals arriving from other neurons. Ions will ow according to identity of channel that was opened and the equilibrium potential. Depending on the identity of the channel that opens this may cause depolarization or hyper polarization. More than one stimulus can be received at once.

Related Questions

26. When it comes to ligand-gated ion channels located in a postsynaptic neuron's membrane, why are they so important with respect to how synapses pass along information?

		These channels allow specific neurotransmitters originating in the presynaptic neuron exert effects on the postsynaptic neuron.
		These channels are located specifically in the dendrites but not another part of the neuron, such as the axon.
		These channels open when a given amount of electrical signal in generated in the cell's membrane.
		These channels allow the neurotransmitter to enter and travel within the postsynaptic neuron.

25. When the receptor of a sensory neuron is activated and a nerve impulse is generated, the first step in the overall process would be ____________________________.

		the potassium channels to open
		the hyperpolarization of the membrane
		the repolarization of the membrane
		the depolarization of the membrane

periwinklecoyote319

1.	Action Potentials
2.	Graded Potentials

Match the characteristic/descriptor in the left-hand column withthe correct type of change in membrane potential listed in theright-hand column.

Question 16 options:

12	propagate along the length of the axon with no decrease inmagnitude as they move away from their site of origin
12	are decremental changes in membrane potential - meaning they arethe type that decrease in magnitude as they spread further fromtheir sites of origin
12	cause an actual reversal of membrane potential during which theinside of the cell membrane temporarily becomes positive withrespect to the outside of the cell membrane
12	are non decremental changes in membrane potential - meaning theypropagate along the plasma membrane with no observable decrease inintensity as they move further and further from their sites oforigin
12	occur in the 'receptive' regions of the neuron - including thecell body and dendrites - in response to opening of ligand-gatedion channels
12	begin at the axon hillock and propagate to the axon terminal
12	occur along the length of the axon in response to opening ofvoltage-gated sodium and potassium ion channels
12	weaken as they spread further and further along the plasmamembrane and away from their site of origin
12	required no 'threshold' change in membrane voltage to occur.
12	occur in 'all or none' fashion

blushjellyfish481

BIOL 2410 Lecture Notes - Lecture 12: Axon Hillock, Axon Terminal, Threshold Potential

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