Chapter 12 Nervous System Nervous Tissue
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
There are ______ different types of glial cells in the CNS.
4
Membrane pumps require ______ energy.
A lot of
Glutamate
Amino acid
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
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
______ are star shaped.
Astrocytes
The plasma membrane of an axon is called the
Axolemma
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
Which are components of the central nervous system?
Brain and spinal cord
The central nervous system is made of the ______ and spinal ______ cord
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
The nucleus of a neuron is found in the ______ of the neuron.
Cell body
Most synapses in the human body are ______ synapses.
Chemical
Which of the following are characteristics of neurons?
Conductivity, excitability, amitotic, extreme longevity, secretion
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
______ is the return of polarity from positive back to negative (the RMP).
Depolarization
Another way for the neurotransmitter to be removed from the synaptic cleft is by ______ where there is uptake by surrounding glial cells.
Diffusion
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
The lining ventricles of the brain is a location of ______.
Ependymal cells
Choose the cells that are part of the central nervous system.
Ependymal cells, oligodendrocyte, astrocyte, and microglia
______ is responsiveness to a stimuli.
Excitability
A larger axon transmits an impulse ______ than a smaller axon.
Faster
A motor neuron is a ______ classification of a neuron.
Functional
The peripheral nervous system is made of nerves and ______
Ganglia
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
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 electrical gradient in a resting neuron is such that the ______ of the cell is negative relative to the ______ .
Inside/interior or cytosol, Outside/exterior/IF or interstitial
Neuronal pools are made of ______.
Interneurons
Dendrites transfer information ______ the cell body.
Into/towards
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
Repolarization is due to the opening of voltage-gated _______ and the subsequent movement of _____ out of the cell.
K+, K+
The myelin sheath is made of a high percentage of ______.
Lipids
Cells that wander through the CNS and replicate in response to infection are called ______
Microglia
Which glial cells remove debris from damaged or dead nervous tissue?
Microglia
Norepinephrine
Monoamine
The brain interprets the increased frequency of nerve signals as a ______ stimulus.
More intense
A damaged axon within the PNS can regenerate if ______.
More neurilemma remains
Which of the following are functional classes of neurons?
Motor neurons, interneurons, and sensory neurons
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
Which of the following pumps can you find in the plasma membrane?
NA+/K+, Ca2+
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+, Ka+
Another name for axon is ______.
Nerve fiber
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
Neuronal pools are also called ______.
Neuronal pathways and 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
______ 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?
Oligodendrocytes
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
Which of the following would be likely to cause hyperpolarization of a neuron?
Opening of a chemically gates chloride channel, opening of a voltage-gated potassium channel
A nerve is part of the ______ nervous system.
Peripheral
Clusters of neuron cell bodies called ganglia are found in the ______ nervous system
Peripheral
Clusters of neuron cell bodies called ganglia are found in 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/proteins
A return of the membrane potential towards the resting membrane potential immediately following depolarization is called ______.
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, Potential
The removal of neurotransmitters from the synaptic cleft by transport into the synaptic knob is known as ______.
Reuptake
Dendrites are ______ than axons
Shorter
Dendrites are ______ than axons.
Shorter
Glial cells are ______ than neurons.
Smaller
The flow of ______ ion is the most common cause of depolarization.
Sodium
Which of the following membrane transporters are present throughout the membrane of a neuron?
Sodium leak channels, Na+/K+ pumps, potassium leak channels
The myelin sheath covers ______.
The axon
The two factors that affect PNS regeneration are ______.
The distance between the injury site and the effector organ, the amount of damage
Which describes the propagation of depolarization down an axon?
The flow of Na+ to downstream regions causes depolarization of adjacent regions
The all-or-none law refers to the fact that action potentials will only occur if the initial segment reaches
Threshold/-55mV
The conductive segment of a neuron is/are the ______.
Total length of the axon
In retrograde transport, substances are moved ______ the cell body.
Toward
Vesicles involved in retrograde transport are moving ______ the cell body.
Toward
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
Pseudounipolar is another name for a ______ neuron
Unipolar
If a subthreshold value is reached on an axon membrane, an action potential ______.
Will not occur
