module 6 Flashcards
what do autonomic motor nerves innervate?
- smooth muscle
- cardiac muscle
- glands
what do autonomic nerves NOT innervate?
skeletal muscle
the peripheral nervous system is divided into what categories?
- sensory divisions
- motor divisions
what correctly describes the efferent division of the PNS?
the efferent division of the PNS transmits impulses form the CNS to skeletal muscle
what division of the nervous system controls smooth and cardiac muscle?
autonomic nervous system
What categories is the autonomic nervous sytem divided into
- sympathetic division
- parasympathetic division
what correctly describes the affernet division of the peripheral nervous system?
the afferent division of the PNS transports action potentials to the CNS
which division of the nervous system controls smooth and cardiac muscle
autonomic nervous system
afferent division of the peripheral nervous system (PNS)
transports action potentials to the CNS
autonomic motor nerves
- innervate smooth muscle
- innervate cardiac muscle
- innervate glands
the peripheral nervous system is divided into
sensory and motor divisions
efferent division of the PNS
transmits impulses from the CNS to skeletal muscle
autonomic nervous system is divided into
sympathetic and parasympathetic divisions
motor neurons
are multipolar
myelin
is a lipid-based material that may be produced in the PNS or CNS
nervous system
- neurons make up over 50% of the weight of the brain
- the function of the neuron is to transmit electrical signals
- The glial cells support and protect
myelinated axon
has a faster conduction rate
the axon hillock
- is at the junction between the axon and the soma
- is the location of spatial summations of EPSPs
- is the location of temporal summation of IPSPs
myelin sheath
prevents ions from crossing the membrane accept at the nodes
which nerve will conduct an action potential the fastest?
myelinated; large-diameter nerve
neurons
are classified by function or structure
the part of a neuron that conducts impulses away from the cell body is called___
an axon
the trigger zone is where action potentials are generated in the neuron. this consists of the
axon hillock
multipolar neurons
have many dendrites with a single axon
which of the following statements accurately describes why an IPSP is inhibitory
an IPSP hyper polarizes the postsynaptic membrane
graded potentials in nerve cells
only EPSPs can generate an action potential
for a nerurotransmitter to reach the postsynaptic membrane it needs to diffuse across the
synaptic cleft
the location of synaptic vesicles containing neurotransmitters
presynaptic axon terminals
the ion that enters a presynaptic axon terminal and that directly causes the release of a neurotransmitter substance from the presynaptic terminal is
calcium
when ion gates open, action potentials tend to occur. correctly match the opening of a specific ion channel to its respective response.
the opening of chloride channels results in and IPSP
which of the following terms correctly describes the junction between two neurons
chemical synapse
which of the following statements is true of chemial synapses
chemicals known as neurotransmitters are released by the presynaptic terminal in chemical synapses
an action potential arriving in close succession at a single presynaptic terminal is
temporal summation
neurotransmitters
cause the production of action potentials in the postsynaptic membrane
the role of a neuromodulator
neuromodulators are compounds that increase the sensitivity of neurons to neurotransmitters
temporal summation
increased frequency of action potentials firing
in a chemical synapse
the neurotransmitter must be removed or inactivated to half the effect on the postsynaptic membrane
a neuron that conduct pain sensations to the central nervous system is classified by
afferent neuron
in general, which type of neuron acts as a motor neuron by sending signals to effector tissues
efferent neurons
spatial summation
increased recruitment of dendrites receiving action potentials
the role of neurotransmitters
neurotransmitters trigger action potentials within the postsynaptic membrane
the axon hillock
is not present in glial cells
EPSP response
typically increases the membrane permeability to sodium ions
capable of causing postsynaptic cell hyperpolarization
both IPSPs and K+ ion movement are capable of causing hyperpolarization
IPSP
causes hyperpolarization
electrical synapse is
cardiac muscle cells
an IPSP
results in hyperpolarization of the postsynaptic membrane
an action potential has the fastest conduction time
with an electrical synapse
an inhibitory local potential
hyperpolarizes the plasma membrane
chemical synapses
- release neurotransmitters into a space, called a cleft, which travels to the next membrane
- do not have direct presynaptic terminal to postynaptic membrane contact
- rely on mitochondria and membrane-bound vesicles as the presynaptic organelles to functionf
the graded potential at the postysnaptic membrane when depolarization occurs is called
excitatory postsynaptic potential
what might occur when multiple action potentials arrive through many different presynaptic neurons onto the same post synaptic neuron
spatial summation
result of an inhibitory postsynaptic potential (IPSP)
cell membrane hyperpolarization
electrical synapses
are gap junctions with a current flowing between adjacent cells
a neuron receives a number of EPSPs from many different neurons. If a sufficient number of EPSPs are received the neuron responds by generating an action potential. what is this process known as?
spatial summation
which of the following is a false statement regarding neurotransmitters
they travel through the bloodstream prior to reaching their target postsynaptic cell
suppose both excitatory and inhibitory neurons synapse with a single postsynaptic neuron. What determines if an action potential is initiated in the postsynaptic neuron
the number of EPSPs in relation to the number of IPSPs
what neuron types is responsible for transporting messages between different neurons
interneurons
chemicals that trigger action potentials within postsynaptic cells
these chemicals are called neurotransmitters and may cause IPSPs or EPSPs
describes the location from which neurotransmitters are released
presynaptic terminal
the role of a neurotransmitter
neurotransmitters are capable of opening and closing ion channels
spatial summation
occurs because of the convergence of many neurons on a single postsynaptic cell
action potentials on a trigger zone are produced
anytime any type of summation reaches threshold
a chemical synapse
may cause a hyperpolarizing graded potential
which of the following are capable of causing postsynaptic cell hyperpolarization
both IPSPs and K+ permeability are capable of causing hyperpolarization
what would happen if the number of boltage-gated Ca++ ion channels in the presynaptic terminal were decreased
the exocytosis of neurotransmitter-containing vesicles would be reduced or inhibited entirely which would have an inhibitory effect on the transmission of action potentials across the synapse
if a neurotransmitter bound to its receptor and increased sodium ion permeability of the postsynaptic membrane
postsynaptic membrane potential would likely exceed threshold, stimulating an EPSP
damage to a postynaptic membrane could result in which of the following
difficulty responding to the presence of a neurotransmitter within a synapse
if both an excitatory and an inhibitory neuron synapsed with the same postsynaptic neuron what would ultimately determien whether and EPSP were initiated or not
the number of EPSPs compared to the number of IPSPs that reach the synapse
which of the following are capable of inhibiting neurotransmitter secretion
blocking Ca++ channels in the presynaptic terminal
- sodium ions diffuse into the postsynaptic cell and stimulate an EPSP in the postsynaptic neuron
- a neurotransmitter binds with a specific receptor on the postsynaptic cell
- a neurotransmitter travels across the synaptic cleft
- postsynaptic cell membrane permeability to sodium ions increases
- an action potential stimualtes the release of a neurotransmitter into the synaptic cleft
5,3,2,4,1
action potentials approach a synapse with increasing frequency. Upon reaching the synapse more and more neurotransmitter is released because of the increasing action potential frequency. The neurotransmitter in this case opens ligand gated Na+ channels. Which of the following are True
1. this sounds like spatial summation
2. we will probably find IPSPs produced in this synapse
3. this sounds like temporal summation
we will probalby find EPSPs produced at this synapse
3 and 4
what might occur when two action potentials arrive simultaneously at the same postsyaptic neuron via two different presynaptic terminals
spatial summation may occur
voltage changes correctly reflects taht caused by EPSP within a neuron
a change in voltage from -70 mv to -69.95 mv
what might occur when multiple action potentials arrive in close succession at the same postsynaptic neuron via the same presynaptic terminal
temporal summation may occur
rapid removal or destruction of neurotransmitter in the synaptic cleft
may affect the ability of the postsynaptic membrane to generate potentials
what would happen if the number of voltage-gated Ca++ ion channels in the presynaptic terminal were decreased
- the transmission of both EPSPs and IPSPs across the synapse would be greatly decreased
- the exocytosis of neurotransmitter-containing vesicles would be reduced or inhibited entirely which would always have an inhibitory effect on the transmission of action potentials across the synapse
the rate at which action potentials are conducted
action potentials are conducted more rapidly along axons with nodes of Ranvier than along axons without nodes of Ranvier
Excitatory neurons A and B both synapse with neuron C. Neuron A releases a neurotransmitter and neuron B releases the same type and amount of neurotransmitter plus a neuromodulator that produces IPSPs in neuron C. Both neuron A and B, when stimulated separately, can product action potential production in neuron C. Which results in more action potentials?
neuron A alone
component of the peripheral nervous system
schwann cells
cells in the nervous system which have various functions related to support and nourishment are called
neuroglia
which glial cell type is responsible for the formation of the blood-brain barrier
astrocyte
cell types is responsible for the formation of myelin within the spinal cord
oligodendrocytes
cells act as phagocytes within the central nervous system
microglial cells
what cell type produces myelin sheaths within the central nervous system
oligodendrocytes
a periodic segment of exposed axon along a myelin sheath is known by which of the following names
node of Ranvier
which of the following is a component of the central nervous system
spinal cord
what glial cell is not found in the cns
schwann cell
which of the following cells makes CSF
ependymal
what is not a glial cell
macroglia
are glial cell
astrocyte
ependymal cell
schwann cell
what cell type produces myelin sheaths within the peripheral nervous system
schwann cells
this cell participates in forming the blood-brain barrier
astrocyte
which glial cell functions by performing phagocytosis with CNS tissue damage
microglia
in the case of a loss of oxygen, which of the following sources will provide the energy necessary to allow the brain to continue functioning for 5-10 minutes
glycogen stored in the astrocytes
what is the difference between schwann cells and oligodenrocytes
oligodendrocytes possess multiple processes which allow them to myelinate multiple segments of axon at one time, while schwann cells are only capable of myelinating a single segment of axon
which of the following is not a function of astrocytes
phagocytose foreign material in the CNS
multiple sclerosis is a neurological disease which destroys myelin sheaths of the central nervous system. Which of the following cell types is damaged as a result of multiple sclerosis
oligodendrocyte
