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69 Cards in this Set
- Front
- Back
highly specialized cells responsible for the conduction of impulses |
neurons |
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what are the 2 forms of communication neurons use?
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chemical and electrical
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this type of communication between neurons occurs via ion exchange and the generation of membrane potentials down the length of the axon |
electrical communication
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this type of communication between neurons occurs via neurotransmitter release from the presynaptic cell and the binding of these neurotransmitters to the postsynaptic cell
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chemical communication |
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where is the nucleus of a neuron found?
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in the soma or cell body
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the soma is the location of the nucleus as well as what other 2 things? |
ribosomes and ER
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appendages emanating directly from the soma that receive incoming messages from other cells |
dendrites
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information received from the dendrites is transmitted through the cell body before it reaches this structure that integrates incoming signals |
axon hillock
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the transmission of electrical impulses down the axon
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action potentials |
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a long appendage that terminates in close proximity to a target structure like a muscle, gland, or another neuron
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axon
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most mammalian nerve fibers are insulated by this to prevent signal loss or crossing of signals
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myelin |
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this maintains the electrical signal within one neuron |
myelin sheath |
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what is myelin produced by in the CNS?
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oligodendrocytes
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what is myelin produced by in the PNS?
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Schwann cells
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small breaks in the myelin shear with exposed areas of axon membrane that are critical for rapid signal conduction |
nodes of Ranvier
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this is at the end of an axon |
nerve terminal or synaptic bouton
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the chemicals that transmit information between neurons
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neurotransmitters |
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the small space into which the terminal portion of the axon releases neurotransmitters |
synaptic cleft |
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together the nerve terminal, synaptic cleft, and postsynaptic neuron are known as what? |
synapse |
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multiple neurons bound together in the PNS |
nerve |
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cell bodies of neurons of the same type in the PNS clustered together |
ganglia
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multiple neurons bound together in the CNS |
tracts |
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cell bodies of neurons clustered together in the CNS
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nuclei
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cells that support neurons in the nervous system
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glial cells or neuroglia |
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these cells nourish neurons and form the blood brain barrier |
astrocytes |
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this controls the transmission of solutes from the blood stream into nervous tissue
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blood brain barrier
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these cells line the ventricles of the brain and produce CSF
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ependymal cells |
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phagocytic cells that ingest and breakdown waste products and pathogens in the CNS |
microglia
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neurons use these all or nothing messages to relay electrical impulses down the axon to the synaptic terminal |
action potentials |
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a single __________ may carry multiple types of information including sensory, motor, or both while _____________ only contain one type of information |
nerve, tracts |
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all neurons exhibit a resting membrane potential of approximately what?
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-70 mV
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What two things help maintain resting potential?
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selective permeability of ions and the Na+/K+ ATPase |
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the Na+/K+ ATPase pumps __ ions of ___________ out of the cell for every ___ ions of ____________ pumped into the cell.
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3 Na+, 2 K+ |
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these type of signals cause depolarization of the neuron
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excitatory
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these type of signals cause hyperpolarization of the neuron |
inhibitory
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this refers to the addition of multiple signals near each other in time |
temporal summation |
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this refers to the addition of multiple signals near each other in space
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spatial summation
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when enough excitatory stimulation occurs the cell is depolarized to what?
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threshold voltage |
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when the cell reaches threshold voltage what happens?
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voltage gated sodium channels open
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sodium flows into the ion due to its strong what?
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electrochemical gradient |
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what is the peak of the action potential?
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35 mV |
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at about 35 mV sodium channels are inactivated and what happens? |
potassium channels open |
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does potassium flow into or out of the neuron due to its strong electrochemical gradient? |
out of |
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potassium channels stay open long enough to overshoot the action potential resulting in a ______________________ neuron |
hyperpolarized
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while the axon is hyperpolarized it is said to be in what?
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its refractory period |
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in this refractory period, the cell is unable to fire another action potential |
absolute refractory period
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in this refractory period the cell requires a larger than normal stimulus to fire an action potential |
relative refractory period |
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at the nerve terminal, neurotransmitters are released into what? |
synapse |
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when the action potential arrives at the nerve terminal what opens?
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calcium channels
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the influx of calcium causes fusion of vesicles filled with neurotransmitters with the presynaptic membrane resulting in what?
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exocytosis of the neurotransmitter
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what 2 types of receptors can neurotransmitters bind to on the postsynaptic cell |
ligand gated ion channels or G protein coupled receptors
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a neurotransmitter can be broken down by what? |
enzymes
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a neurotransmitter can be absorbed back into the presynaptic cell by what?
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reuptake channels
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a neurotransmitter can diffuse out of what? |
synaptic cleft
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what are the 3 types of neurons in the nervous system?
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sensory, motor and interneurons |
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the brain and spinal cord |
central nervous system |
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the cranial and spinal nerves
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peripheral nervous system
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these nerve cells are often linked to reflexive behavior |
interneurons |
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what 2 cranial nerves are technically not a part of the PNS |
optic and olfactory
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in the CNS what does white matter consist of? |
myelinated axons
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in the CNS what does grey matter consist of?
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unmyelinated cell bodies and dendrites
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in the brain is white matter or grey matter deeper? |
white matter |
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in the spinal cord is white matter or grey matter deeper?
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grey matter |
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what are the 2 divisions of the PNS?
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somatic and autonomic |
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what are the 2 divisions of the autonomic nervous system? |
sympathetic and parasympathetic
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these use the ability of interneurons in the spinal cord to relay information to the source of a stimulus while simultaneously routing it to the brain |
reflex arcs
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in this type of reflex arc, the presynaptic neuron fires directly on to the postsynaptic neuron |
monosynaptic reflex arc |
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in this type of reflex arc, the presynaptic neuron may fire onto a motor neuron as well as interneurons that fire onto other motor neurons
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polysynaptic reflex arc
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the additive effect of multiple signals |
summation
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