Homework: Chapter 12: Nervous System
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 ________ channels.
potassium
Voltage is a measure of relative ________ energy.
potential
Membrane molecule 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
The function of a neuron is dependent on ________.
resting membrane potentials changing
Na+ and K+ leaks 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
Glial cells are ________ than neurons.
smaller
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 two factors that affect PNS regeneration are ________.
the distance between the injury site and the effector organ; the amount of damage
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
Vesicles involved in retrograde transport are moving ________ the cell body.
toward
The measure if the difference in electrical change between two areas is called a __________.
voltage
If a subthreshold value is reached on an axon membrane, an action potential __________.
will not occur
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 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 neurons. 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
Actin potentials are always propagated along an axon at the same ________ but ________ can vary depending on the strength of the stimulus.
Amplitude; frequency
Which glial cell occupies the space of dying neurons?
Astrocytes
Which are components of the central nervous system?
Brain and spinal cord
Which of the following pumps can you find in the plasma membrane?
Ca2+ and Na+/K+
The main activity of the ________ is the propagation of an action potential along the axolemma.
Conductive segment
A positive change in the membrane potential is called __________.
Depolarization
The choroid plexus is made from capillaries and _________.
Ependymal cells
Which of the following are characteristics of neurons?
Excitability; Conductivity; Secretion; Neurotransmitters; Extreme longevity; Amitotic
True or False: A neuromodulator is another name for a neurotransmitter.
False
Match the neurotransmitter to its class.
Glutamate --> Amino acid Norepinephrine --> Monoamine
Match the neurotransmitter with its correct class.
Glycine --> Amino Acid Dopamine --> Monoamine Neuropeptide --> Enkephalin
Which glial cells remove debris from damaged or dead nervous tissue?
Microglia
Which glial cells removes debris from damaged or dead nervous tissue?
Microglia
Cells that wander through the CNS and replicate in response to infection are called __________.
Microglial
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+
_________ are released from neurons in response to conductive activity.
Neurotransmitters
Which of the following membrane transporters are present throughout the membrane of a neuron?
Potassium leak channels; Sodium leak channels; Na+/K+ pumps
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.
_________ 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.
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 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
___________ are star shaped.
astrocytes
The myelin sheath covers _________.
axon
A nerve is a bundle of parallel ___________.
axons
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+
The presence of ________ ions causes the synaptic vesicles to bind to the membrane, allowing neurotransmitters to be released.
calcium
The brain and spinal cord are part of the ______.
central nervous system
Synapses are classified as ___________.
chemical synapses and electrical synapses
Another way for the neurotransmitter to be removed from the synaptic cleft is by _________ where there is uptake by surrounding glial cells.
diffusion
A difference in the number of charged particles between two sides of the membrane forms a(n) ____________.
electrical
Creating and transmitting _________ currents is central to the function of neuron physiology.
electrical
The lining ventricles of the brain is a location of _____________.
ependymal cells
________ is responsiveness to a stimuli.
excitability
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 very in size is called a __________ potential.
graded
Glial cells are found ____________.
in both the central and peripheral nervous system
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 in the membrane potential is ___________.
it becomes less positive and more negative
The myelin sheath is made of a high percentage of ___________.
lipids
The myelin sheath is made of a high percentage of ____________.
lipids
The brain interprets the increased frequency of nerve signals as a __________ stimulus.
more intense
Most motor neurons are _________.
multipolar
_________ neurons are most common.
multipolar
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
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
Neuronal pools are also called ________.
neuronal circuits neuronal pathways
The components of nervous tissue that conduct electrical impulses are _________.
neurons
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
