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