BIOL 215 Study Guide - Midterm Guide: Myelin, Saltatory Conduction, Membrane Potential

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harlequinmule917

4 Apr 2016

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Channels in the membrane that produce an electrical signal transmittable to another part of the cell membrane. A change in membrane potential that the neuron uses as signals occur because of . The change in permeability of the cell membrane to ions. Changes in membrane potential in a small region of the membrane. + inside the cell sort of move to the side to make way for new +. Almost like creating a current for + to come in. Result: depolarization around the area of the targeted membrane part. Decremental: flow of charge decreases across the membrane the farther you are from the original site. Types of graded potential: receptor (ipsp/epsp)(can add up), synaptic, pacemaker (funny channel- where the sympathetic and parasympathetic pathway can affect heart rate. Larger than graded potentials, rapid, and can occur at high frequencies. The propagation of action potentials down the axon. Na+ opens and inactivates very quickly (quick response time to voltage change)

Related Questions

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

Santiago Ramon y Cajalâs theory of dynamic polarization refers to the:

(a)membrane potential of a neuron at rest.

(b)membrane potential of a neuron firing action potentials.

(c)opening and closing of gated channels in the membrane.

(d)one way flow of information in neurons from dendrites to axon terminals.

(e)one way flow of information in neurons from axon terminals to dendrites.

Over the course of scientific history, there are many examples of scientists reaching the right conclusion for the wrong reasons. When Schwann first proposed that the nervous system was made of individual cells, he based it on observations of:

(a)synapses.

(b)dendrites

(c)axon terminals.

(d)astrocytes.

(e)Nodes of Ranvier.

The synaptic cleft was finally seen in the 1950s. What prevented scientists from seeing it earlier?

(a)The resolution of the light microscope.

(b)They were looking in the wrong place.

(c)Their tissue was not appropriately stained.

(d)Myelination of the axons.

(e)all of the above

The resting membrane potential of a neuron is approximately:

(a) +65 V

(b) +65 mV

(d) -65 mV

What is largely responsible for the resting membrane potential in a neuron?

(a)Axonal insulation by myelin

(b)Voltage-Gated Sodium Channels

(c)The Action Potential

(d)Potassium Leak Channels

Which of the following would DECREASE the propagation velocity of an action potential down an axon?

(a)Increase in axon diameter

(b)Increase myelination between nodes of Ranvier

(c)Remove myelination between nodes of Ranvier

(d)Decrease density of voltage-gated Na+ channels except at the Nodes of Ranvier

The resting membrane potential of a neuron can be estimated using the:

(a)Nernst equation

(b)Goldman equation

(c)Hodgkin and Huxley equation

(d)Ohmâs law

18. What would happen to the resting membrane potential of a neuron if you added K+ to the extracellular fluid?

(a)Resting membrane potential would increase (become more positive)

(b)Resting membrane potential would decrease (become more negative)

(c)Resting membrane potential would not change

(d)Resting membrane potential would be abolished

. Which of the following statements is FALSE for Graded Potentials

(a)Magnitude changes with magnitude of triggering stimulus

(b)Magnitude decreases with distance from initial site

(c)Cannot be summed

(d)No refractory period

In the nervous system, the strength of the stimulus is coded into:

(a)The frequency of action potentials generated

(b)The amplitude of action potentials generated

(c)Both the frequency and amplitude of action potentials generated

(d)The duration of individual action potentials generated

Ion movement during both the depolarization and repolarization phases of an action potential are the result of:

(a)active transport pumps along the neuron membrane.

(b)diffusion of ions down their electrochemical concentration gradients.

(c)negative feedback loops.

(d)All of the above

At the peak of the action potential, the membrane potential is:

(a)Exactly at the Na+ equilibrium potential

(b)Greater (more positive) than the Na+ equilibrium potential

(c)Above 0 mV but less positive than the Na+ equilibrium potential

(d)0 mV

The junction specialized for the transmission between a neuron and another cell is called a (1) _____ ______. Usually, the signal being sent to the receiving cell is carried by chemical messengers called (2) _____. (3) _____ is an example of this type of chemical messenger, which diffuses across the synaptic cleft, combines with protein receptor molecules on the muscle cell membrane, and soon thereafter is rapidly broken down by enzymes. At an (4) ____ synapse, the membrane potential is driven toward the threshold value and increases the likelihood that depolarization and an action potential will occur. At an (5) ____ synapse, the membrane potential is driven away form the threshold value, and the receiving neuron becomes hyperpolarized and is less likely to achieve an action potential. A specific transmitter substance can have either excitatory or inhibitory effects depending on which type of protein channel it opens up in the (6) ____ membrane. (7) ____ are neuromodulators that inhibit perceptions of pain and may have roles in memory and learning, emotional states, temperature regulation, and sexual behavior. (8) ____ ________ at the cellular level is the moment-by-moment tallying of all excitatory and inhibitory signals acting on a neuron. Incoming information is (9) ____ by the cell bodies, and the charge differences across the membranes are either enhanced or inhibited. Some narrow-diameter neurons are wrapped in lipid-rich (10) _______ produced by specialized neuroglial called Schwann cells; each of these is separated from the next by a(n) (11) ________ ________ - a small gap where the axon is exposed to extracellular fluid. A (12) ____ is an involuntary sequence of events elicited by a stimulus. During a (13) _______ ________, a muscle contracts involuntary whenever conditions cause a stretch in length; many of these help you maintain an upright posture despite small shifts in balance. Imbalances can occur at chemical synapses; a neurotoxin produced by Clostridium tetani blocks the release of GABA and glycine, thus freeing the motor neurons from (14) _____ control, which may cause tetanus â a prolonged, spastic paralysis that can lead to death. A. Excitatory H. Stretch reflex B. Inhibitory I. Summed C. Myelin J. Neurotransmitters D. Chemical synapse K. Postsynaptic E. Synaptic integration L. Endorphins F. Exposed node M. Acetylcholine (ACh)

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BIOL 215 Study Guide - Midterm Guide: Myelin, Saltatory Conduction, Membrane Potential

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