anatomy exam 3. mcgraw hill nervous system homework

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

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

-Na+/K_ -Ca2+

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

-Soduim leak channels -Potassium leak channels -Na+/K+ pumps

Which of the following are characteristics of neurons?

-amitotic -secretion -excitability -extreme longevity -conductivity

The functions of astrocytes are to ______.

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

Place the events of an EPSP in order.

1) The excitatory neurotransmitter binds to the 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.

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 within the neuron 3)The membrane potential becomes more positive 4) Voltage-gated sodium ion channels open

match the neurotransmitter with its correct class 1) Glycine 2) Dopamine 3) Neuropeptide

1) amino acid 2) monoamine 3) enkephalin

A substance synthesized at the cell body must undergo ______ transport to reach the synaptic knobs.

Anterograde

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

K+/K+

Which glial cells remove debris from damaged or dead nervous tissue?

Microglia

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+

Which describes the propagation of depolarization down an axon?

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

______ neurons have a single, short neuron process that emerges from the cell body and branches like a T.

Unipolar

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

amplitude, frequency

The voltage-gated sodium channels ______ during repolarization.

are inactivated

The voltage-gated potassium channels ______ during repolarization.

are open

Which glial cell occupies the space of dying neurons?

astrocytes

A nerve is a bundle of parallel

axons or fibers

Cytoplasm within an axon is called ______.

axoplasm

A synapse is a junction ______.

between a neuron and another cell

Unipolar neurons start out as ______ neurons during development.

bipolar

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

both Na+ and K+

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

calcium

The nucleus of a neuron is found in the ______ of the neuron.

cell body

The brain and spinal cord are part of the ______.

central nervous system

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

______ is the type of neuronal circuit that is made when multiple impulses come together at a single postsynaptic neuron.

converging

A positive change in the membrane potential is called ______.

depolarization

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

depolarization

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

depolarization

Another way for the neurotransmitter to be removed from the synaptic cleft is by ______ where there is uptake by surrounding glial cells.

diffusion

A message traveling from one presynaptic neuron to multiple postsynaptic neurons is an example of a ______ circuit.

diverging

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

electrical

Synapses are classified as ______.

electrical and chemical

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

______ is responsiveness to a stimuli.

excitability

An increase in the response of a postsynaptic neuron to a neurotransmitter is known as ______.

facilitation

True or false: A neuromodulator is another name for a neurotransmitter.

false

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

faster

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

hyperpolarization

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

hyperpolarization

Glial cells are found ______.

in both the central and peripheral nervous system

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

increase

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 myelin sheath is made of a high percentage of ______. Multiple choice question.

lipids

______ act as phagocytes.

microglial cells

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

more intense

Most motor neurons are ______.

multipolar

______ neurons are most common.

multipolar

Oligodendrocytes create the _____ sheath in the central nervous system.

myelin

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

myelin

A cablelike bundle of axons in the peripheral nervous system is called a ______.

nerve

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

nerve impulse

What is the primary tissue of the nervous system?

nervous tissue

The ability to alter the response of neurons to neurotransmitters is known as ____

neuromodulation

Neuromodulation alters the response of ______ to neurotransmitters.

neurons

The components of nervous tissue that conduct electrical impulses are ______.

neurons

______ are released from neurons in response to conductive activity.

neurotransmitters

The neuron cell body houses both the ______ and the cytoplasm.

nucleus

Which neuroglial cells insulate axons in the central nervous system? Multiple choice question.

oligodendrocytes

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

potassium

Voltage is a measure of relative _____ energy.

potential or electrical

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____

pump

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

pumps

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

repolarization

The function of a neuron is dependent on ______.

resting membrane potentials changing

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

resting, membrane

The removal of neurotransmitters from the synaptic cleft by transport into the synaptic knob is known as ______.

reuptake

A ______ is a type of circuit that causes a cyclic response.

reverberating

The repetitious nature of a ______ circuit ensures that we continue breathing while we are asleep.

reverberating

Glial cells are ______ than neurons.

smaller

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

sodium

The myelin sheath covers ______.

the axon

The all-or-none law refers to the fact that action potentials will only occur if the initial segment reaches _____.

threshold

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

total length of the axon

In retrograde transport, substances are moved ______ the cell body.

toward

True or false: Facilitation and inhibition may be caused by changes in either the presynaptic neuron or the postsynaptic neuron.

true

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

true

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

true

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

voltage