Nervous System Smartbook

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

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 a type of membrane transport protein that increases the potential energy across a membrane.

A pump

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

Na+

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

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

______ are released from neurons in response to conductive activity.

Neurotransmitters

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

Repolarization

______ (is) are the slightly expanded region at the tip of the fine terminal extensions of a neuron.

Synaptic knobs

The refractory period occurs immediately ______ an action potential.

after

An epineurium surrounds ______.

an entire nerve

Neuronal pools are made of ______.

interneurons

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

nerve

Another name for axon is ______.

nerve fiber

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

nerve impulse

The thin outer layer of the neurolemmocyte is called the ______.

neurilemma

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

neuromodulation

A damaged axon within the PNS can regenerate if ______.

some neurilemma remains

Neurons integrate multiple synaptic inputs by the process of ______.

summation

The process by which postsynaptic potentials are added together at the initial segment is known as _____.

summation

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

the all-or-none law

______ is a typical resting membrane potential for a neuron.

-70 millivolts

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

There are ______ different types of glial cells in the CNS.

4

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

Ca2+ Na+/K+

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

False

True or false: Ion channels use the energy of ATP to maintain concentration gradients across neuron membranes.

False

True or false: The relative charge across a neuron's plasma membrane is negative outside the cell relative to the inside of the cell.

False

______ to help return the membrane potential to the resting state following hyperpolarization.

Na+/K+ pumps restore gradients Voltage-gated potassium channels close

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.

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

______ and are the cause of hyperpolarization in an action potential.

Voltage-gated potassium channels remain open

Membrane pumps require ______ energy.

a lot of

The relative refractory period occurs ______ the absolute refractory period.

after

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

amplitude; frequency

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

an increase

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

anterograde

The voltage-gated sodium channels ______ during repolarization.

are inactivated

The voltage-gated potassium channels ______ during repolarization.

are open

The perivascular feet of the ______ help create a blood-brain barrier.

astrocyte

Which glial cell occupies the space of dying neurons?

astrocyte

Choose the cells that are part of the central nervous system.

astrocyte oligodendrocyte microglia ependymal cells

The plasma membrane of an axon is called the _____.

axolemma

The myelin sheath covers ______.

axon

A fascicle is a bundle of ______.

axons

A nerve is a bundle of parallel _____.

axons

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+

Identify all of the components of the central nervous system.

brain spinal cord

Which are components of the central nervous system?

brain and spinal cord

The central nervous system is made of the _____ and spinal _____.

brain, cord

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

calcium

Dendrites branch off of the ______.

cell body

Soma is another name for the ______.

cell body

The ______ is the structural division of the nervous system that contains the brain.

central nervous system

The ependymal cells help produce ______.

cerebrospinal fluid

Ependymal cells produce and circulate cerebrospinal fluid. The ______ helps circulate the CSF.

cilia

Ganglia are ______.

clusters of neuron cell bodies

The total length of the axon is called the _____ segment.

conductive

The epineurium is made of ______ connective tissue.

dense irregular

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

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

diffusion

Glial cells ______ transmit electrical impulses.

do not

The tissues that receive nerve impulses from motor neurons are called ______.

effectors

Motor neurons are classified as ______ neurons.

efferent

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 lining ventricles of the brain is a location of ______.

ependymal cells

______ is responsiveness to a stimuli.

excitability

Which of the following are characteristics of neurons?

excitability secretion amitotic conductivity extreme longevity

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

faster

A motor neuron is a ______ classification of a neuron.

functional

Neurons are classified ______ depending on the direction the nerve impulse travels.

functionally

Sensory input and motor output are used to divide the nervous system ______.

functionally

The peripheral nervous system is made of nerves and _____.

ganglia

A cluster of neuron cell bodies found along a peripheral nerve is known as a(n) _____.

ganglion

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 chromatophilic substance helps create the ______ color in parts of the brain and spinal cord.

gray

Negatively charged proteins and other large organic molecules are found in ______.

greater amounts inside a neuron

Immediately following the repolarization of an action potential, the membrane undergoes _____ before returning to the resting membrane potential.

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 changes in membrane potential associated with both EPSP and IPSP inputs are "added" in the ______ to determine if an action potential is initiated and the threshold is reached.

initial segment

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

inside, outside

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 ______.

lipids

It usually takes ______ neurolemmocytes to myelinate one axon.

many

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

microglia

______ act as phagocytes.

microglial cells

The resting membrane potential is measured in ______.

millivolts

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

more intense

Which of the following are functional classes of neurons?

motor neurons sensory neurons interneurons

If a neuron has many dendrites and a single axon, it is called a(n) ______ neuron.

multipolar

______ neurons are most common.

multipolar

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

myelin

What is found in the ganglia of spinal nerves?

neuron cell bodies

Neuronal pools are also called ______.

neuronal pathways neuronal circuits

Nervous tissue is composed of glial cells and _____.

neurons

Neuromodulation alters the response of ______ to neurotransmitters.

neurons

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

neurons

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

nucleus

Which neuroglial cells insulate axons in the central nervous system?

oligodendrocytes

_____ are large cells that ensheath many different axons.

oligodendrocytes

Which of the following would be likely to cause hyperpolarization of a neuron?

opening of a chemically gated chloride channel opening of a voltage-gated potassium channel

Which of the following would be likely to cause depolarization of a neuron?

opening of a chemically gated sodium channel opening of a voltage-gated sodium channel

A fascicle is surrounded by a layer of dense irregular connective tissue called ______.

perineurium

Clusters of neuron cell bodies called ganglia are found in the ______ nervous system.

peripheral

Spinal nerves are part of the ______ nervous system.

peripheral

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

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

An axon is either incapable of generating an action potential or requires a larger than normal stimulus during the _____ period.

refractory

The functions of astrocytes are to ______.

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

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

repolarization

The function of a neuron is dependent on ______.

resting membrane potentials changing

The relative difference in charge across the plasma membrane of a resting neuron is known as the _____ _____ _____.

resting, membrane, potential

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

resting, potential

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

reuptake

Chromatophilic substance and Nissl bodies are both types of _____.

ribosomes

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

sodium

The two factors that affect PNS regeneration are ______.

the distance between the injury site and the effector organ the amount of damage

If summated PSPs reach a threshold, an action potential begins first in ______.

the initial segment

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

Dendrites transfer information _____ the cell body.

toward

Vesicles involved in retrograde transport are moving ______ the cell body.

toward

The blood-brain barrier helps protect the brain from ______.

toxins

Most afferent neurons are classified functionally as ______.

unipolar

Most sensory neurons are ______.

unipolar

Pseudounipolar is another name for a ______ neuron

unipolar

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

voltage