FAM &CS 21 Lecture Notes - Lecture 11: Axon Hillock, Exocytosis, Myelin

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rubywallaby21

13 Nov 2020

School

LACC

Department

Family And Consumer Studies

Course

FAM &CS 21

Professor

Huatah

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Document Summary

The inside of the membrane becomes positively charged in relation to the outside how neurons transfer information from one location to another from the axon hillock to the axon terminal. During an action potential, the membrane potential briefly becomes positive. Action potential can be explained by the movement of ions through channels that are gated by changes in the membrane potential. Phases of action potential= electrical transmission: resting potential/threshold. Membrane potential where the voltage gated sodium channels open. Selective: favor sodium over potassium because sodium channels have a filter that make them more permeable to sodium than potassium. They open/close because of changes in voltage = -55mv. Na+ is attracted to the inside of the membrane which has a negative electrical potential. New sodium coming in through the open sodium channels. The sodium influx goes everywhere because of diffusion. This causes depolarization (the inside of the membrane becomes less negative)

Related Questions

1.A stronger stimulus to a neuron results in ________.

A. larger voltage changes in graded potentials and greater frequency of action potentials produced in response

B. greater frequency of graded potentials and larger voltage changes in the action potentials produced in response

C. larger voltage changes in the graded potentials, but no changes in action potentials

D. larger voltage changes in both graded and action potentials

E. larger voltage changes in graded potentials but smaller action potentials

2. Why is it more difficult to fire an action potential when the interval between stimuli decreases?

A. because sodium is flowing out of the cell

B. because potassium is flowing into the cell

C. because some sodium channels may still be in an inactivated state

D. because chloride is flowing into the cell

E. because chloride is flowing out of the cell

3. As an action potential zips down an axon,

A. voltage gated potassium channels open first followed by voltage-dependent sodium channels

B. voltage- gated sodium channels ahead of the wave and not yet activated are influenced by the depolarizing electrical field of other nearby sodium channels

C. voltage-gated potassium channels ahead of the wave and not yet activated are influenced by the depolarizing electrical field of nearby sodium channels

D. leak channels are opened by the wave of electricity passing along the axon

E. B and C

Which of the following statements is FALSE? (choose one)

A.	Voltage-gated sodium (Na+) channels open in the dendrites and cell body during a local, graded potential.

B.	During repolarization, potassium ions are leaving the cell (K+ is diffusing out of the cell), and the inside of the cell becomes more negative

C.	If someone damaged an efferent motor neuron, they could feel pain, but not respond to move away from the pain

D.	Myelin serves as electrical insulation and increases the speed at which an action potential travels along the axon

E.	Movement of ions can be excitatory (if sodium ligand-gated channels bind the neurotransmitter), or inhibitory (if potassium ligand-gated channels bind the neurotransmitter)

i choose aba for those 3 neuroscience question. but could any one help me if i got right?

5. Patch clamp studies have demonstrated that the following is trueâ¦

a. individual channels carry currents that do not predict the macroscopic current carried by the entire population in an axon

b. ion selectivity varies greatly among individual channels of a particular type (e.g. voltage-gated sodium channels)

c. channel behavior includes random fluctuations

d. individual voltage-gated sodium and potassium channels always open when the membrane is depolarized

7. The following is true regarding membrane property known as thresholdâ¦

a. it is primarily determined by the phospholipid composition of the membrane

b. it is strongly dependent upon the voltage-dependence of the voltage-gated sodium channels

c. it usually occurs when the membrane is hyperpolarized beyond the resting potential

d. it occurs when there is less depolarizing current than the leakage currents e. mutations in the sodium channel S4 domain would not be expected to influence threshold

8. Which of the following is a potential advantage of electrical synapses over chemical synapses?

a. their strength can be modulated at many different steps of synapse function

b. neurotransmitters can bind to distinct receptor types present at the same synapse

c. they can allow second messengers to pass between neurons

d. signals can pass more slowly preventing over-stimulation in the brain e. they help ensure that neurons are not synchronously active

FAM &CS 21 Lecture Notes - Lecture 11: Axon Hillock, Exocytosis, Myelin

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