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91 Cards in this Set
- Front
- Back
a. regulating / controlling peripheral structures and system b. providing sensation of the internal / external environments c. coordinating voluntary and involuntary activities |
general functions if the nervous system |
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The CNS includes the ____________ and _______________. |
brain spinal cord |
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Which nervous system controls skeletal muscles? |
somatic |
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Which nervous system controls smooth muscles of the visceral organs? |
ANS |
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Which cells are the supporting cells of the nervous system? However these cells do not get involved in information processing. |
neuroglia |
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a. secretion of CSF b. BBB: isolation of neurons c. Defense: phagocytosis d. providing support of the neuron (myelin sheath formation) |
functions of the neuroglia |
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Only the _____________ is responsible for information processing. NEUROGLIA IS NOT. |
neuron |
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a. astrocytes b. oligodendrocytes c. ependymal cells d. microglia |
four types of neuroglia in the CNS |
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What are the two types of neuroglia in the PNS? |
Schwann cells and satellite cells |
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a. maintaining BBB (blood-brain barrier) b. guiding neuron development c. repairing damaged tissue d. controlling the interstitial environment surrounding neurons |
Major functions of the ASTROCYTES |
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What do the oligodendrocytes do? |
form MYELIN sheath around axon in the CNS |
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Cell that myelinated several parts of several axons |
oligodendrocytes |
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Which cells for myelin sheets on the PNS |
schwann cells |
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Myelinates a single axon |
each schwann cell |
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___________________ increases the speed of the conduction of a nerve impulse |
myelin |
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Damage to which cell would result in decreased speed of action potential? |
oligodendrocytes |
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A disease in which myelin sheet is abnormal due to autoimmune antibodies = demyelination |
multiple sclerosis |
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Which cells produce CSF (cerebral spinal fluid)? |
ependymal cells |
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Which cells are small phagocytes? |
microglia |
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Which cells are the largest and most numerous of the glia cells in the CNS? |
astrocytes |
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Which cells have the least number of neuroglia in the CNS? |
microglia |
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_________________ is the cytoplasm surrounding the nucleus of the neuron. |
perikaryon |
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Aggregations of fixed and free ribosomes in neurons. |
nissls bodies |
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An area that the axon connects to the soma (cell body). |
hillock |
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The actual site of information processing in the nervous system... |
axonal hillock |
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Branches that sometimes occur along the length of an axon. |
collaterals |
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Terminal end of an axon that contains a series of fine extensions. |
telodendria |
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Where are the neurotransmitters released from? |
synaptic knobs to the synaptic cleft |
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A series of fine extensions at the axon terminal... |
synaptic knobs
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The site of intercellular communication between neurons. |
synapse |
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Cellular materials move from axon terminal to the cell body to be degraded or recycled. rabies, herpes, and polio viruses can travel to the CNS via this means. |
retrograde transport |
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neuron in which dendrites and axon are continuous and the cell body (SOMA) lies OFF to one side. |
uniploar neuron (sensory neuron for general senses) |
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neurons have ONE axon and ONE dendrite |
bipolar neuron (sensory neuron for special senses) |
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i. neurons have several dendrites and ONE SINGLE axon ii. multipolar neurons are the most common type of neuron in the nervous system |
multipolar neurons (motor neurons) |
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Where is the axon of the unipolar neuron found? |
dorsal root of the spinal cord |
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Where is the cell body of the unipolar neuron found? |
dorsal root of the ganglion of the spinal cord |
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Where is the axon of the multipolar neuron found? |
on the ventral root of the spinal cord |
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Where is the cell body of the motor neuron found? |
on the anterior gray horn on the spinal cord |
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a. by diffusion of potassium out of the cell (easy) b. by diffusion of sodium ions into the cell (difficult) c. by an excess of negatively charges protein molecules in the interior of the cell membrane of the neuron (neurilemma) |
the resting potential of a membrane of the neuron (neurilemma) is established by... |
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What are membrane channels that are always OPEN called? |
PASSIVE channels or Leak channels |
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Which type of channels can OPEN or CLOSE in response to binding of particular substance with specific receptors? |
chemically-gated channels (LIGAND-GATED CHANNELS) |
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A stimulus that opens the GATED CHANNELS produces a ___________________. |
GRADED POTENTIAL |
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OPENING of chemically-gate SODIUM channel results in what? |
depolarization |
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CLOSING of SODIUM channels and opening of POTASSIUM channels in the membrane of a neuron results in what? |
repolarization |
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At the end-phase of an action potential, additional POTASSIUM IONA exit from the cell membrane of a neuron results in what? |
hyperpolarization (because the chemically-gated potassium channel remains open after repolarization) |
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a. chemical and electrical forces push SODIUMS into the cell b. chemical forces tend to drive POTASSIUM ions out of the cells c. potassium ions are attracted to negative charges inside the cell (electric gradient) |
interactions between electrical and chemical gradient lead to establishment of a neuron's resting membrane |
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SODIUM IONS (Na+) ____________ the cell membrane exit or enter |
enter |
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POTASSIUM IONS (K+) ___________ the cell membrane exit or enter |
exit |
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CALCIUM IONS (Ca+) _____________ the cell membrane to trigger the releasing of neurotransmitter (such as acetylcholine or epinephrine/norepinephrine) exit or enter |
enter |
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Where can VOLTAGE-REGULATED SODIUM CHANNELS be found? |
in the membrane that covers axons |
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The SODIUM-POTASSIUM exchange pump requires ____________ to operate. The process involves in exchange 3 intracellular SODIUM IONS for 2 extracellular POTASSIUM IONS. |
ATP |
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When cholinergic receptors are stimulated, SODIUM IONS ____________ the postsynaptic neuron. enter or exit |
enter |
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What contributes to maintaining the resting membrane potential (-70mV) |
SODIUM-POTASSIUM exchange pump |
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Which principle states that all stimuli GREAT enough to bring the membrane to the THRESHOLD will produce INDENTICAL action potentials? |
ALL-OR-NONE |
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____________ potential includes depolarization, depolarization and hyperpolarization. |
graded |
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GRADED POTENTIAL ____________ spread across the membrane surface (local only). The potential becomes weaker and weaker and finally disappears (detrimental effect) can or cannot |
cannot |
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The refractory period would be _____________ if voltage sodium channels failed to become inactivated. longer or shorter |
longer |
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During which phase do local currents depolarize adjacent areas of membrane so that action potentials continue to be generated along the membrane... |
continuous conduction |
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During which phase do action potential occur at SUCCESSIVE NODES along the length of the stimulated axon? |
saltatory conduction |
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Neurons ____________ regenerate because of LACK OF CENTRIOLES. can or cannot |
cannot |
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a. presence or absence of myelin sheath (faster spend with myelin sheath) b. length of axon (the shorter, the faster the speed) c. diameter of the axon (the larger the axon, the faster the speed) |
factors that influence the TIME (velocity) necessary for a nerve impulse |
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Which type of fiber is the largest, myelinated fiber, and therefore it conducts the greatest rate of impulse? |
type A |
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Which type of fiber is responsible for relaying SENSORY information concerning touch, position and balance? |
type A |
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Which ion is needed to initiate the release of acetylcholine in the synaptic cleft of the NEURON? |
calcium ion |
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______________ synapse is a synapse in which acetylcholine (Ach) is released at the synaptic cleft. |
cholinergic |
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_______________ synapse is a synapse in which epinephrine or nor-epinephrine (e/ne) is released at the synaptic cleft. |
adrenergic |
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The effect that a neurotransmitter has on the postsynaptic membrane depends on the ____________________________, not a nature or characteristic of the neurotransmitters. |
characteristics of the receptors |
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__________________ or ______________ is usually and EXCITATORY neurotransmitter (EPSP). |
nor-adrenaline epinephrine |
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_________________ may be and EXCITATORY or and INHIBITORY receptor depending on what kind of receptor at the synapse |
acetylcholine |
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Resting membrane potential is _______________ in muscle fibers lower or greater |
greater
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speed of conduction is ______________ in the muscle fibers lower or greater |
lower |
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action potentials last _________________ in the muscle fibers (long duration) shorter or longer |
longer |
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Muscle fibers ONLY conduct action potential via __________________ conduction. |
continuous |
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What type of conduction do neurons use to conduct action potential? |
both continuous and saltatory |
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The minimum amount of stimulus required to depolarize and excitable membrane and generate AP |
threshold |
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The period of time which an excitable membrane CAN respond again, BUT ONLY if the stimulus is GREATER than the initial stimulus |
relative refractory period |
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The period of time during which an excitable membrane CANNOT respond again, regardless the intensity of the stimulus |
absolute refractory period |
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The action potential traveling along an axon is called what? |
nerve impulse |
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EPSP's occur when sodium channels open, resulting in? |
depolarization |
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IPSP's occur when potassium channels open, resulting in? |
local hyperpolarization |
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___________________ occurs when a second EPSP arrives at a single synapse before the effects of the first have disappeared |
temporal summation |
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_____________________ is the addition of stimuli arriving at DIFFERENT LOCATIONS on the same time to produce and AP |
spatial summation |
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Neurons normally derive ATP solely through what? |
Aerobic metabolism |
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a. synthesis of neurotransmitters b. releasing of neurotransmitters c. movement of material to and from SOMA via axoplasmic flow d. recovery from an action potential e. recycling of neurotransmitters f. stimulating sodium-potassium pump |
active neurons need ATP because ATP is used for these functions |
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deteriorating changes at the distal segment of an axon as a result of a break between it and the soma (cell body) |
Wallerian degeneration |
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These cell participate in the repair of damages nerves by FORMING A CELLULAR TUBE OR CHANNEL that can direct the growth of new axons. |
Schwann cells |
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________________ is a process in which the Nissl bodies break up into fine granular masses. |
Chromatolysis |
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________________________ occurs when the release of SEROTONIN activates chemically gated CALCIUM channels in the presynaptic neuron membrane. The calcium channel opens longer. Therefore the postsynaptic neurons become more and more excited (EPSP). |
presynaptic facilitation |
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_____________________ occurs when the release of GABA inactivates chemically gated CALCIUM channels open the postsynaptic neurons become more and more inhibited (IPSP). |
pre-synaptic inhibition |
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a. glutamate and aspartate are excitatory neurotransmitters in the CNS b. GABA and glycine are inhibitory neurotransmitter in the CNS |
several amino acids are neurotransmitters in the CNS |
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_________________ is different from other neurotransmitters because it is not synthesized in advance and packaged into synaptic vesicles. Rather, it is formed on demand and acts immediately. |
nitric oxide |