Nervous Tissue Connect Assignment

Voltage is a measure of relative energy.

potential

Voltage represents ______ energy.

potential

Propagation of depolarization only flows away from the cell body towards the synaptic knob because ______.

previous regions in the axon have sodium channels in the inactive state

Membrane molecules that use the energy of ATP to move ions against a concentration gradient are called .

pumps

A return of the membrane potential towards the resting membrane potential immediately the following depolarization is called ______.

repolarization

Na+ and K+ leak channels and Na+/K+ pumps on the neuron are responsible for establishing and maintaining the membrane .

resting potential

The function of a neuron is dependent on ______.

resting membrane potentials changing

"An action potential either happens or it doesn't." This statement could also be called ______.

the all-or-none law

True or false: Graded potentials vary in size depending on the stimulus.

true

The voltage-gated sodium channels undergo changes in activity during the depolarization phase of an action potential. Place these in order from first to last.

1. the membrane potential is -70 mv. 2. sodium ions flow into the neuron. 3. the membrane potential becomes more positive. 4. voltage-gated sodium ion channels open.

Match the type of circuit to the corresponding letter.

A- converging B- diverging C- reverberating D- parallel-after-discharge

Action potentials are always propagated along an axon at the same ______ but ______ can vary depending on the strength of the stimulus.

Amplitude/ Frequency

Which of the following pumps can you find in the plasma membrane?

Ca2+ Na+/K+

Repolarization is due to the opening of voltage-gated _______ and the subsequent movement of _____ out of the cell.

K+/K+

The threshold is reached when the ______ ions flow into the cell.

Na+

The nerve impulse has the voltage-gated ______ channels opened first followed by the opening of the voltage-gated ______ channels.

Na+; K+

True or false: Voltage-gated sodium ion channels are closed initially and the membrane potential is -70 mv.

True

The voltage-gated sodium channels ______ during repolarization.

are inactivated

The myelin sheath covers ______.

axon

Many excitatory neurotransmitters cause the opening of channels that allow for the flow of ______.

both Na+ and K+

The ependymal cells help produce ______.

cerebrospinal fluid

The total length of the axon is called the segment.

conductive

The main activity of the ______ is the propagation of an action potential along the axolemma.

conductive segment

The type of circuit letter A represents is a circuit.

converging

A positive change in the membrane potential is called ______.

depolarization

Glial cells ______ transmit electrical impulses.

do not

Creating and transmitting currents is central to the function of neuron physiology.

electrical

A difference in the number of charged particles between two sides of the membrane forms a(n) ______.

electrical gradient

The choroid plexus is made from capillaries and ______.

ependymal cells

A larger axon transmits an impulse ______ than a smaller axon.

faster

Match the neurotransmitter to its class.

glutamate = amino acid norepinephrine = monoamine

The event that occurs when the inside of a cell becomes more negative than the resting membrane potential is called .

hyperpolarization

The electrical gradient in a resting neuron is such that the of the cell is negative relative to the .

inside outside

Neuronal pools are made of ______.

interneurons

During an action potential, voltage-gated potassium channels open after voltage-gated sodium channels. The effect this has on the membrane potential is ______.

it becomes less positive and more negative

The brain interprets the increased frequency of nerve signals as a ______ stimulus.

more intense

Neuronal pools are also called ______.

neuronal pathways neuronal circuits

Place the events of an EPSP in order.

1. Excitatory neurotransmitter binds to chemically gated cation channel 2. More Na+ enters the postsynaptic cell than K+ leaves 3. The inside of the cell becomes more positive 4. The local current of Na+ becomes weaker as it moves towards the axon hillock

______ is the return of polarity from positive back to negative (the RMP).

Repolarization

Which describes the propagation of depolarization down an axon?

The flow of Na+ to downstream regions causes depolarization of adjacent regions.

The nerve impulse causes ______ in the number of calcium ions that enter the synaptic knob.

an increase

The voltage-gated potassium channels ______ during repolarization.

are open

The presence of ______ ions causes the synaptic vesicles to bind to the membrane, allowing neurotransmitters to be released.

calcium

The event that occurs when the inside of the cell becomes more positive (less negative) than the resting membrane potential is called .

depolarization

Match the neurotransmitter with its correct class.

glycine = amino acid dopamine = monoamine neuropeptide = enkephalin

A potential that is a temporary change in membrane potential which lasts only as long as the stimulus that causes it and can vary in size is called a potential.

graded

The presence of a sheath increases the rate of impulse conduction.

myelin

A ______ is the propagation of an action potential along an axon.

nerve impulse

The sequential opening of voltage-gated sodium channels is followed by the sequential opening of voltage-gated channels.

potassium

Which of the following membrane transporters are present throughout the membrane of a neuron?

potassium leak channels sodium leak channels Na+/K+ pumps

The functions of astrocytes are to ______.

regulate the composition of interstitial fluid help form the blood-brain barrier assist neuronal development

The flow of ______ ion is the most common cause of depolarization.

sodium

The conductive segment of a neuron is/are the ______.

total length of the axon

The measure of the difference in electrical charge between two areas is called a .

voltage

If a subthreshold value is reached on an axon membrane, an action potential ______.

will not occur

Initially, the voltage-gated Na+ channels are closed and the membrane potential is ______ mV. As Na+ flows in the membrane potential changes to ______ mV and the threshold is reached.

-70; -55