A&P Smartbook CH 12

Match the neurotransmitter to its class. Glutamate norepinephrine

- amino acid - monoamine oxid

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

The electrical gradient in a resting neuron is such that the ____of the cell is negative relative to the ___

-Inside -outside

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

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

Neuronal pools are also called ______.

-Neuronal pathways -Neuronal circuits

Match the neurotransmitter with its correct class. Glycine Dopamine Neuropeptide

-amino acid -monoamine -enkephalin

Synapses are classified as ______.

-chemical synapses -electrical synapses

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. 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

The two factors that affect PNS regeneration are ______.

1. the amount of damage 2. the distance between the injury site and the effector organ.

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

Match the structure with the appropriate letter in the given image of a neuron.

A. Dendrites B. Axon C. Axon Collateral D. Terminal Extensions

Match the structure with the appropriate letter in the illustration of a neuron.

A. Necleous B. Cell Body C. Neurolemmoncyte D. Node

The brain and spinal cord are part of the ______.

CNS (central nervous system)

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+

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

Na+/K+ Ca2+

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

Na+; K+

______ are released from neurons in response to conductive activity.

Neurotransmitters

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

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

True

Membrane pumps require ______ energy.

a lot of

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

Which glial cell occupies the space of dying neurons?

astrocytes

A synapse is a junction ______.

between a neuron and another cell

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

both Na+ and K+

Which are components of the central nervous system?

brain and spinal cord

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

calcium

The ependymal cells help produce ______.

cerebrospinal fluid

Most synapses in the human body are ______ synapses.

chemical

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

conductive segment

The total length of the axon is called the

conductive segment

A positive change in the 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

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

______ is responsiveness to a stimuli.

excitability

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

graded

Glial cells are found ______.

in both the central and peripheral nervous systems

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 ______.

lipids

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

microglia

Cells that wander through the CNS and replicate in response to infection are called

microglial

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

more intense

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

multipolar

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

multipolar

Most motor neurons are ______.

multipolar

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

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

neuromodulation

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

A nerve is part of the ______ nervous system.

peripheral

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

potassium, K+, or K

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 or proteins

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

resting membrane potential

The function of a neuron is dependent on ______.

resting membrane potentials changing

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

reuptake

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

sodium

A damaged axon within the PNS can regenerate if ______.

some neurilemma remains

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

the all-or-none law

The myelin sheath covers ______.

the axon

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

toward

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

will not occur