NERVOUS SYSTEM

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Ion movement across the postsynaptic membrane as a result of neurotransmitter binding

may depolarize or hyperpolarize the postsynaptic neuron

Which statement is CORRECT?

Depolarization refers to the process where the neuronal membrane becomes more positive

Which statement is CORRECT?

Hyperpolarization results in a membrane potential that is more negative than the resting membrane potential.

Which postsynaptic potential is more negative than the resting membrane potential

IPSP

Excitable cells are most permeable to which of the following ions?

K+

The part of a neuron that conducts impulses away from its cell body is called a(n)

axon

What gradient(s) would tend to move Na+ into the cell?

both electrical and concentration gradient

an increase in what ion at the axon terminal region of the presynaptic neuron results in a neurotransmitter release

calcium

A neurotransmitter is the chemical signal that opens voltage-gated ion channels

false

Ion channels allow for the random movement of all ions across the neuronal cell membrane.

false

The rising phase of the action potential ends when the permeability of K+ decreases.

false

a normal synaptic potential is higher in amplitude than an action synaptic potential

false

A cell that received ten EPSPs and two IPSPs to the axon hillock would most likely

generate an action potential

Nongated (passive) channels are located?

in the cell membrane of the entire neuron

The sheath of Schwann cells that aids in regeneration is also called the

neurolemma

Substances that bind to chemically gated channels of neurons are known as

neurotransmitters

chemically gated channels are located?

on dendrites and the cell body

voltage gated channels are located?

on the axon, hillock, all along the unmyelinated axons, the nodes of ranvier, and in the myelinated axons.

Depolarization is caused by the movement of what ion in what direction?

potassium; out of the cell

Which event happens immediately after a neurotransmitter binds to its postsynaptic membrane receptor?

chemically gated ion channels open

When a neuron is at rest, voltage gated channels are

closed

Which of the following would increase membrane permeability to K+?

closing voltage-gated K+ channels

Which of the following describes the nervous system's integrative function?

senses change, processes information, and makes a decision

Open voltage-gated sodium channels result in

sodium moving into the cell

Increasing the number of synapses from different neurons would cause which type of summation?

spatial summation

which event occurs immediately after extracellular calcium enters the axon terminal region

synaptic vesicles fuse with the membrane

Increasing the number of action potentials on a presynaptic axon in a given period of time would cause what type of summation?

temporal summation

Inhibitory synapses have the maximum effect if they are located on what part of the neuron?

the cell body, near the axon hillock

if an inhibitory postsynaptic potential occurs at the same time as an excitatory postsynaptic potential

the magnitude of the excitatory postsynaptic potential will be reduced and may be cancelled out all together

which statement is correct

the mechanism by which neurotransmitters are returned to the terminal is specific to each neurotransmitter

what happens to synaptic potentials as they travel away form the synapse

they weaken

Chemically gated ion channel opens when a specific neurotransmitter binds to it.

true

During an action potential, voltage-gated sodium channels open rapidly, then inactivate, and finally reset to the closed state.

true

It takes many EPSP to depolarize a neuron threshold

true

Membrane proteins known as ion channels allow ions to flow across the neuronal cell membrane.

true

Synapses located a great distance from the axon hillock will be less likely to trigger an action potential

true

Threshold refers to the voltage that opens the voltage-gated channels located in the axon hillock region of the neuron

true

Voltage-gated potassium channels open when the action potential reaches its peak

true

When and only when a neuron reaches threshold, a positive feedback loop for opening sodium channels is established?

true

the job of a neuron is to select a single output from competing inputs

true

At the end of the depolarization phase, what voltage-gated channels open to help restore the resting membrane potential?

voltage gated K+ channels

Which potentials decay as they move along the neuronal membrane?

Both EPSPs and IPSPs

When the neurotransmitter binds to a receptor located on the postsynaptic membrane

NOT all answers correct!!!

one of the roles of a convergent neural pathway is

NOT decrease the need for complex neural pathways!!! NOT enhanced release of neurotransmitter NOT TO INCREASE CELLULAR INTEGRATION

As the axon hillock depolarizes

Na+ moves down its electrochemical gradient

This change is caused by the opening of ___ then ____ voltage-gated channels

Na+ then K+

Voltage-gated channels

Responsible for generation and propagation of the outgoing signal, the action potential

Chemically gated channels

Responsible for incoming signals, the synaptic potentials

Passive (nongated) channels

Responsible for the resting membrane potential of the neuron

Which of the following describes the nervous system's sensory function?

Senses changes in the internal and external environment.

which statement is incorrect

a synapse near the axon hillock has less influence on the generation of an action potential than one farther away

Rapid firing of presynaptic action potentials will result in

all answers are correct

The rising phase of an action potential ends when

all answers are correct

When an action potential reaches the end terminal region of a presynaptic neuron

all answers are correct

The rising phase of an action potential ends when

all of the above

When threshold is reached

all statements are correct

As the axon hillock depolarizes, Voltage-gated Na+ channels open and Na+ moves (into or out of) __________ the cell causing further (depolarization or repolarization)

into; depolarization

potentiation/facilitation of a synaptic potential is caused by

keeping the postsynaptic membrane potential slightly depolarized

A positive ion moving into a cell would result in a membrane potential that

less negative


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