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224 Cards in this Set

  • Front
  • Back
What four things is the nervous system composed of?
brain, spinal cord, nerves, ganglia
What are the 3 general functions of the nervous system?
Collect information
Process and evaluate information
Initiate response to information
Specialized nervous system cells
neurons
_____ are specialized nervous system structures that monitor changes in both the internal and external environment called stimuli
Receptors
Changes to the internal and external environment is called _____
stimuli
_____ include all three types of muscle tissue and glands.
Effectors
What are the different types of effectors controlled by the nervous system?
All three types of muscle tissue and glands
What are the two anatomic divisions of the nervous system?
central nervous system (CNS)
peripheral nervous system (PNS)
____ includes the brain and spinal cord
CNS
_____ includes nerves and ganglia
PNS
_____ are bundles of neuron processes (axons)
nerves
____ are clusters of neuron cell bodies located along nerves
ganglia
What are the two functional divisions of the nervous system?
sensory and motor
_____ is responsible for receiving sensor information FROM receptors that detect stimuli and transmitting this information TO the CNS.
sensory nervous system
How is the sensory nervous system subdivided?
somatic (conscious)
visceral (automatic)
Receptors of the somatic sensory nervous system include:
eyes, nose, tongue, ears, skin, proprioreceptors
Receptors in muscle and joints that detect body position
proprioreceptors
_____ sensory components detect stimuli that we don't consciously perceive
visceral sensory components
Receptors of the visceral sensory nervous system include:
structures located within blood vessels and internal organs, e.g., heart, stomach, kidneys
What is another name for the motor nervous system?
efferent nervous system
The _____ is responsible for initiating and transmitting motor output FROM the CNS TO effectors
motor nervous system
This system controls muscle tissue and glands
motor nervous system
Is the motor nervous system subdivided into somatic and visceral parts
yes
The _____ component initiates and transmits motor output from the CNS to voluntary skeletal muscles
somatic motor
what is the other name for autonomic motor nervous system?
visceral motor
the visceral motor component of the motor nervous system innervates and regulates:
cardiac muscle, smooth muscle, and glands
What are the two subdivisions of the autonomic nervous system?
sympathetic; parasympathetic
_____ is the primary tissue of the nervous system.
Nervous tissue
nervous tissue is composed of two distinct cell types:
neurons and glial cells
_____ are excitable cells that initiate and transmit electrical signals.
neurons
_____ cells are nonexcitable cells that primarily support and protect neurons
glial cells
Neurons have several special characteristics including:
excitability
conductivity
secretion
extreme longevity
amitotic
This is a responsiveness to stimulation
excitability
The type of stimulation that a neuron responds to is dependent upon ______
its location
Most neurons usually respond only to binding of secreted molecules called _____
neurotransmitters
neurotransmitters are released from
other neurons
These are electrical changes that are quickly propagated along the plasma membrane of neurons following stimulation
conductivity
Neurons release neurotransmitters in response to _____
conductive activity
How many types of neurotransmitters does a typical neuron release?
only one type
a neurotransmitter may have either ___ or ___ effect on its target organ
excitatory or inhibitory
T/F
most neurons formed during fetal development are still functional in very elderly individuals
True
When is mitotic development lost in most neurons?
during fetal development of neurons
What are the exceptions to loss of mitotic development of neurons during fetal development?
olfactory epithelium of the nose and certain areas of the brain
This region of the brain is involved in memory processing:
hippocampus
This region of the brain contains a population of neural stem cells
hippocampus
What are the basic structural features of a neuron?
cell body, dendrites, an axon
What is another name for a cell body?
soma
What is another name for a soma?
cell body
a cell body is enclosed by a _____
plasma membrane
a cell body has _____ surrounding a nucleus
cytoplasm
_____ serve as the neuron's control center
cell bodies
_____ conduct electrical signals to the axon
cell bodies
electrical signals can either be initiated _____ or _____
within the cell body;
received from the dendrites
What is the cytoplasm within a neuron cell body called?
perikaryon
Ribosomes are formed in ___ in a neuron
nucleolus
Where is the nucleolus in a neuron?
The nucleus
_____ occurs at approx 400 millimeters per day and involves movement along microtubules.
Fast axonal transport
_____ occurs at apprix .1 - 3 millimeters per day and results from the flow of the axoplasm, also called axoplasmic flow.
Slow axonal transport
______ are the most common type of neuron
multipolar neurons
These neurons have many dendrites and a single axon that extends from the cell body.
Multipolar neurons
_____ have two processes that extend from the cell body - one dendrite and one axon.
bipolar neurons
The location of these neurons is relatively limited in humans eg retina of the eye and olfactory mucosa in the nasal cavity
bipolar neurons
In what two locations can bipolar neurons be found in humans?
retina of the eye, olfactory mucosa in the nasal cavity
What are the three categories of functional classification of neurons?
Sensory neurons
Motor neurons
Interneurons
Are most sensory neurons unipolar, bipolar, multipolar, or anaxonic? What are the exceptions?
unipolar
retina and nasal mucosa are bipolar
All motor neurons are unipolar, bipolar, multipolar, or anaxonic?
multipolar
Where do the cell bodies fo the motor neurons lie?
In the CNS
What is another name for sensory neurons?
afferent neurons
What is another name for afferent neurons?
sensory neurons
What is another name for motor neurons?
efferent neurons
What is another name for efferent neurons?
motor neurons
what is another name for interneurons?
association neurons
what is another name for association neurons
interneurons
Interneurons lie entirely within the ___
CNS
_____ facilitate communication between sensory and motor neurons
interneurons
_____ outnumber all other neurons
interneurons
it is estimated that ____% of our neurons are _____
interneurons
Interneurons are generally multipolar, unipolar, bipolar, anaxonic
multipolar
A _____ is a cable-like bundle of parallel axons that are components of the PNS
nerve
A nerve is a cable-like bindle of parallel axons that are components of the _____
PNS
A thick layer of dense irregular connective tissue that encloses the entire nerve and provides both support and protection.
Epineurium
What is the epineurium?
A thick layer of dense irregular connective tissue that encloses the entire nerve and provides both support and protection
a layer of dense irregular connective tissue that wraps fascicles, which are bundles of axons. This layer supports blood vessels
perineurium
What is the perineurium?
a layer of dense irregular connective tissue that wraps fascicles, which are bundles of axons. This layer supports blood vessels.
This layer of connective tissue wrappings supports blood vessels
perineurium
An individual axon in a myelinated neuron is surrounded by _____, then wrapped in the _____
neurolemmocytes; endoneurium
What kind of connective tissue separates and insulates each axon as part of the endoneurium?
areolar
What separates and electrically insulates each axon?
endoneurium (areolar connective tissue)
Within which connective tissue layer lie capillaries that supply each axon?
endoneurium
_____ nerves extend from the brain
cranial nerves
_____ nerves extend from the spinal cord
spinal nerves
What are the two structural classifications of nerves?
cranial nerves and spinal nerves
What are the three functional classifications of nerves?
sensory nerves, motor nerves, mixed nerves
Sensory nerves relay information (to/from) the CNS
to
Motor nerves relay information (to/from) the CNS
from
What are the three connective tissue wrappings in a nerve, and what specific structure does each ensheathe?
Epineurium; entire nerve
perineurium; fascicles or bundles of axons
endoneurium; each axon
The specific location where a neuron is functionally connected to either another neuron or an effector
synapse
What is a synapse?
The specific location where a neuron is functionally connected to either another neuron or an effector
What are the two types of synapses in the human body?
chemical; electrical
Most synapses within the nervous system are _____ synapses (chemical, electrical)
chemical
A _____ synapse is composed of a presynaptic neuron, which is a signal producer, and a postsynaptic neuron, which is the signal receiver or target
chemical synapse
A chemical synapse is composed of a ______ which is a signal producer and a _____ which is the signal receiver
presynaptic neuron; postsynaptic neuron
in regards to a chemical synapse, which is the signal producer and which is the signal receiver or target?
presynaptic is the producer
postsynaptic is the receiver or target
Transmission between a pre and post synaptic neuron occurs when _____ molecules stored in synaptic vesicles are released from the synaptic knob of a presynaptic neuron into the synaptic cleft.
neurotransmitter molecules
There is a ______ associated with neurotransmitter release at chemical synapses.
synaptic delay
What causes the synaptic delay?
release of neurotransmitter from presynaptic cell, the diffusion across the synaptic cleft, and the binding to receptors in the postsynaptic plasma membrane.
An _____ is composed of a presynaptic and postsynaptic neuron fused together
electrical synapse
_____ are present in the plasma membranes of both neurons and facilitate the flow of ions between cells in electrical synapses
gap junctions
Is there synaptic delay with electrical synapses?
no
Which has synaptic delay? Chemical synapses or electrical synapses?
chemical synapses
Where are electrical synapses in the body?
limited regions of the brain and the eyes
what kind of synapses are in limited regions of the brain and the eyes?
electrical synapses
Are glial cells excitable?
No
What is the primary function of glial cells?
to support and protect the neurons
What is another name for glial cells?
neuroglia
Are glial cells found in both the CNS and PNS?
yes
what is another name for neuroglia
glial cells
Are glial cells larger or smaller than neurons?
smaller
Are glial cells capable of mitosis?
Yes
Do glial cells transmit nerve signals?
no
The _____ cells cooperate to physically protect and help nourish neurons as well as provide an organized, supporting scaffolding for all the nervous tissue.
glial
During development, _____ cells form the framework that guides young, migrating neurons to their final destinations.
glial cells
Do glial cells outnumber neurons or vice versa
glial cells outnumber neurons
_____ account for roughly half of the volume of the nervous system
glial cells
Large cel with numerous cell processes; in contact with neurons and capillaries; most common type of glial cell
Large cel with numerous cell processes; in contact with neurons and capillaries; most common type of glial cell
Astrocyte
Helps form the blood-brain barrierRegulates tissue fluid compositionProvides structural support and organization to the CNSAssists with neuronal developmentReplicates to occupy space of dying neurons
Helps form the blood-brain barrierRegulates tissue fluid compositionProvides structural support and organization to the CNSAssists with neuronal developmentReplicates to occupy space of dying neurons
Astrocyte
Simple cuboidal or columnar epithelial cells that line cavities in brain and spinal cord; cilia on apical surface
Simple cuboidal or columnar epithelial cells that line cavities in brain and spinal cord; cilia on apical surface
Ependymal cell
Lines ventricles of brain and central canal of spinal cordAssists in production and circulation of cerebrospinal fluid (CSF)
Lines ventricles of brain and central canal of spinal cordAssists in production and circulation of cerebrospinal fluid (CSF)
Ependymal cell
Small cell with slender branches from cell body; least common type of glial cell
Small cell with slender branches from cell body; least common type of glial cell
Microglial cell
Defends against infectious agents and engulfs debris from dead or dying neurons
Defends against infectious agents and engulfs debris from dead or dying neurons
Microglial cell
Rounded, bulbous cell with slender cytoplasmic extensions; extensions wrap around CNS axons
Rounded, bulbous cell with slender cytoplasmic extensions; extensions wrap around CNS axons
Oligodendrocyte
Myelinates and insulates CNS axonsAllows faster action potential conduction along axons in the CNS
Myelinates and insulates CNS axonsAllows faster action potential conduction along axons in the CNS
Oligodendrocyte
Flattened cell; groups of these cells cluster around neuronal cell bodies in a ganglion
Flattened cell; groups of these cells cluster around neuronal cell bodies in a ganglion
Satellite cell
Protects and regulates nutrient and waste exchange for cell bodies in ganglia
Protects and regulates nutrient and waste exchange for cell bodies in ganglia
Satellite cell
flattened cell wrapped around a portion of an axon in the PNS
flattened cell wrapped around a portion of an axon in the PNS
Neurolemmocyte
Myelinates and insulates PNS axons and allows for faster action potential conduction along an axon in the PNS
Myelinates and insulates PNS axons and allows for faster action potential conduction along an axon in the PNS
Neurolemmocyte
What are the four types of glial cells found in the CNS?
What are the four types of glial cells found in the CNS?
astrocytes, ependymal cells, microglia, and oligodendrocytes
astrocytes, ependymal cells, microglia, and oligodendrocytes are:
astrocytes, ependymal cells, microglia, and oligodendrocytes are:
The four types of glial cells found in the CNS
These glial cells of the CNS have a star-like shape
astrocytes
Astrocyte glial cells of the CNS have projections that touch both _____ and _____
capillary walls, neurons
_____ are the most abundant glial cell in the CNS and constitute over 90% of the nervous tissue in some areas of the brain
Astrocytes
Astrocytes nurture, protect, support, and guide neurons in these 5 ways:
help form the blood - brain barrier
regulate tissue fluid composition
form a structural network
assist neuronal development
occupy the space of dying neurons
The ends of astrocyte processes are called _____
perivascular feet
What are perivascular feet?
The ends of astrocyte processes
The _____ and the _____ together contribute to a blood brain barrier (BBB)
perivascular feet; capillaries
The _____ strictly controls movement of tubstances from exiting the blood and entering the nervous tissue in the brain
Blood-brain barrier (BBB)
How do astrocytes help regulate the chemical composition of the interstitial fluid within the brain ?
controlling movement of ions and molecules between the blood and the interstitial fluid
The cytoskeleton in _____ strengthens and organizes nervous tissue in the CNS by forming a framework to support neurons
astrocytes
_____ help direct the development of neurons in the fetal brain by secreting chemicals that regulate the formation of connections between neurons
astrocytes
When neurons are damaged and die, the space they formerly occupied is often filled by cells produced by ______ _______, a process termed astrocytosis.
astrocyte division
The process of astrocyte division is called _____
astrocytosis
_____ are ciliated simple cuboidal or simple columnar epithelial cells that line the internal cavities of the brain and spinal cord
_____ are ciliated simple cuboidal or simple columnar epithelial cells that line the internal cavities of the brain and spinal cord
Ependymal cells
What shapes can ependymal cells be?
What shapes can ependymal cells be?
Simple cuboidal or simple columnar
What forms the choroid plexus?
What forms the choroid plexus?
ependymal cells and capillaries
What helps produce cerebral spinal fluid (CNS)?
choroid plexus
What is CNF?
A clear liquid that bathes the external surfaces of the CNS and fills its internal cavities.
A clear liquid that bathes the external surfaces of the CNS and fills its internal cavities.
Cerebral spinal fluid
What is the purpose of the cilia on ependymal cells?
What is the purpose of the cilia on ependymal cells?
To help circulate CSF
What helps circulate CNF?
What helps circulate CNF?
The cilia on ependymal cells
These are typically small cells that have slender branches extending from the main portion of the cell
These are typically small cells that have slender branches extending from the main portion of the cell
Microglia
This type of glial cell represents the smallest percentage of CNS glial cells
This type of glial cell represents the smallest percentage of CNS glial cells
microglial cells
This type of glial cell is classified as a phagocytic cell of the the immune system
This type of glial cell is classified as a phagocytic cell of the the immune system
Microglial cells
Microglial cells wander through the CNS and replicate in response to _______
Microglial cells wander through the CNS and replicate in response to _______
an infection
These glial cells in the CNS protect against microorganisms and other potentially harmful substances by engulfing infectious agents and removing debris from dead or damaged nervous tissue
These glial cells in the CNS protect against microorganisms and other potentially harmful substances by engulfing infectious agents and removing debris from dead or damaged nervous tissue
microglial cells
How many types of glial cells are found in the PNS?
Two
What are the two types of glial cells found in the PNS?
Satellite cells; neurolemmocytes
_____ are flattened cells arranged around neuronal cell bodies in a ganglion.
_____ are flattened cells arranged around neuronal cell bodies in a ganglion.
Satellite cells
What is a ganglion?
a collection of neuron cell bodies located outside the CNS
_____ physically separate cell bodies in a ganglion from their surrounding interstitial fluid
_____ physically separate cell bodies in a ganglion from their surrounding interstitial fluid
satellite cells
_____ regulate the exchange of nutrients and waste products between neurons and their environment in the PNS
_____ regulate the exchange of nutrients and waste products between neurons and their environment in the PNS
satellite cells
What is another name for neurolemmocytes?
What is another name for neurolemmocytes?
Schwan cells
What is another name for Schwan cells?
What is another name for Schwan cells?
neurolemmocytes
These flattened cells ensheathe PNS axons to form a myelin sheath
These flattened cells ensheathe PNS axons to form a myelin sheath
neurolemmocytes
These are large cells with a bulbous body and slender cytoplasmic extensions or processes (CNS)
These are large cells with a bulbous body and slender cytoplasmic extensions or processes (CNS)
oligodendrocytes
The processes of _____ (CNS) ensheathe portions of axons of many different neurons
The processes of _____ (CNS) ensheathe portions of axons of many different neurons
oligodendrocytes
The wrapping around an axon by either an oligodendrocyte or neurolemmocyte
myelin sheath
This protective covering around the axon insulates and prevents the passage of ions through the axonal membrane. This allows for faster action potential propagation within the CNS
myelin sheath
If a person suffers from meningitis, which type of glial cell usually replicates in response to the infection?
If a person suffers from meningitis, which type of glial cell usually replicates in response to the infection?
Microglia
Which specific type of glial cells ensheaths axons in the PNS?
Which specific type of glial cells ensheaths axons in the PNS?
Neurolemmocytes
_____ is the process by which part of an axon is wrapped with myelin.
Myelination
_____ is the insulating covering around the axon that consists of repeating concentric layers of plasma membrane of glial cells
myelin
Myelination is completed by _____ in the PNS and by _____ in the CNS
neurolemmocytes; oligodenrocytes
The high _____ content of the myelin gives an axon a distinct, glossy-white appearance and serves to effectively insulate the axon
lipid
The wrapped inner portion of a neurolemmocyte on an axon is called the
myelin sheath
The outer-most part of the neurolemmocyte around an axon is made up of _____ and _____ and is called the _____
The outer-most part of the neurolemmocyte around an axon is made up of _____ and _____ and is called the _____
cytoplasm, nucleus; neurilemma
A neurolemmocyte in the PNS can myelinate only a _____ mm portion of an axon
1
The gaps between the neurolemmocytes are called _____
The gaps between the neurolemmocytes are called _____
neurofibril nodes
what is another name for a neurofibril node?
nodes of Ranvier
What is another name for nodes of Ranvier?
neurofibril nodes
What is the difference between what a neurolemmocyte and an oligodendrocite can myelinate?
What is the difference between what a neurolemmocyte and an oligodendrocite can myelinate?
a neurolemmocyte can only myelinate a 1 mm portion of a PNS axon at a time. an oligodendrocyte can myelinate a 1mm portion of multiple axons of the CNS at a time.
Is a neurilemma formed with CNS myelination?
Is a neurilemma formed with CNS myelination?
No
Is a neurilemma formed with PNS myelination?
Yes
Are neurofibril nodes between oligodendrocyte myelin sheaths on an axon?
Are neurofibril nodes between oligodendrocyte myelin sheaths on an axon?
Yes
Are all axons myelinated?
No
Are PNS unmyelinated axons associated with the neurolemmocyte?
Yes, they rest in a depression within the neurolemmocyte, but no sheathe is wrapped around the axon.
Are CNS unmyelinated axons associated with oligodendrocytes?
No
What is the function of the myelin sheathe?
Insulation
Can a damaged PNS axon regenerate and if so under what conditions?
Yes, if the cell body remains intact and a critical amount of neurilemma remains.
The success of PNS axon regeneration depends upon two primary factors:
1 - the amount of damage
2 - the distance between the site of the damaged axon and the structure it innervates
the possibility of repair decreases with an increase of either of these two factors.
______ play an active role in PNS axon regeneration
______ play an active role in PNS axon regeneration
neurolemmocytes
The process of axon regeneration (PNS) follows what stages? (5)
The process of axon regeneration (PNS) follows what stages? (5)
What are some of the reasons regeneration of damaged neurons within the CNS is very limited?
1 - oligodendrocytes do not release a nerve growth factor and actively inhibit axon growth by producing and secreting several growth-inhibitory molecules. 2 - the large number of axons crowded within the CNS tends to complicate regrowth activities. 3 - both astrocytes and connective tissue coverings may form some scar tissue that obstructs axon regrowth.
Neurons contain _____ proteins for moving substances across the plasma membrane
transport
_____ move substances up (against) a concentration gradient, a process that requires energy
_____ move substances up (against) a concentration gradient, a process that requires energy
Pumps
Why do pumps require energy?
Why do pumps require energy?
Because they are moving substances against a concentration gradient.
The plasma membrane of neurons contains both ____ pumps and _____ pumps
sodium-potassium (Na+/K+)
calcium (Ca2+)
_____ provide the means to move a substance down (with) the concentration gradient
channels
List the major types of channels (3)
Leak (passive) channels
Chemically gated channels
Voltage-gated channels
What is another name for leak channels?
What is another name for leak channels?
passive channels
What is another name for leak channels?
What is another name for leak channels?
Passive channels
These channels are always open, allowing continuous diffusion of a specific type of ion from a region of high concentration to a region of low concentration.
These channels are always open, allowing continuous diffusion of a specific type of ion from a region of high concentration to a region of low concentration.
Leak channels
These channels are normally closed and open in response to binding of a neurotransmitter.
These channels are normally closed and open in response to binding of a neurotransmitter.
Chemically gated channels
These channels are normally closed and open in response to changes in electrical charge (potential) across the plasma membrane
These channels are normally closed and open in response to changes in electrical charge (potential) across the plasma membrane
Voltage-gated channels
Most voltage-gated channels have one gate that is in one of two states; open or closed. _____ voltage-gated channels are unique because they have two gates.
Most voltage-gated channels have one gate that is in one of two states; open or closed. _____ voltage-gated channels are unique because they have two gates.
Na+
What are the two gates of a Na+ voltage-gated channel?
What are the two gates of a Na+ voltage-gated channel?
activation gate and inactivation gate
What are the activation gate and inactivation gate?
What are the activation gate and inactivation gate?
The two gates of Na+ voltage-gated channels
What are the three states of voltage-gated Na+ channels?
What are the three states of voltage-gated Na+ channels?
1 - Resting state
2 - Activation state
3 - Inactivation state
Describe the resting state of the voltage-gated Na+ channels.
Describe the resting state of the voltage-gated Na+ channels.
Although the inactivation gate is open, the activation gate is closed and entry of Na+ is prevented.
Describe the activation state of the voltage-gated Na+ channels.
Describe the activation state of the voltage-gated Na+ channels.
Both the inactivation gate (which remains open) and the activation gate are open (activation gate opens in response to a voltage change); Na+ moves into the cell through the open channel.
Describe the inactivation state of the voltage-gated Na+ channels.
Describe the inactivation state of the voltage-gated Na+ channels.
Although the activation gate is open, the inactivation gate is TEMPORARILY closed (for several milliseconds) following activation of the Na+ channel - during this time, it cannot be stimulated to reopen, and entry of Na+ is prevented. (The resting state of voltage-gated Na+ channels is reestablished as the inactivation gate opens and the activation closes.)
What pumps and/or channels are located throughout the entire neuron plasma membrane of a neuron?
What pumps and/or channels are located throughout the entire neuron plasma membrane of a neuron?
Na+ leak channels, K+ leak channels, and Na+/K+ pumps
These are important in establishing and maintaining the resting membrane potential of neurons.
These are important in establishing and maintaining the resting membrane potential of neurons.
Na+ leak channels, K+ leak channels, and Na+/K+ pumps
A typical neuron is functionally organized into these four segments:
A typical neuron is functionally organized into these four segments:
1 - receptive segment
2 - initial segment
3 - conductive segment
4 - transmissive segment
T/F Each of the four segments of a typical neuron differs in the primary types of channels and pumps located within its plasma membrane
T/F Each of the four segments of a typical neuron differs in the primary types of channels and pumps located within its plasma membrane
True