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191 Cards in this Set
- Front
- Back
The two major organs of the CNS include the______ in the cranial cavity and the _______ in the spinal cavity |
brain, spinal cord |
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The brain and spinal cord are covered by a triple-layered set of fibrous connective tissue membranes, called the: |
meninges |
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Description of dura mater |
dense, irregular fibrous connective tissue, outermost membrane |
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Description of pia mater |
delicate membrane layer, highly vascularized |
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Description of arachnoid mater |
loose membrane layer, middle layer |
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The primary purpose of these connective tissue membranes is _____________of the brain and spinal cord. |
protection |
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This space between the arachnoid and pia mater is called the ____________ space, it contains ______________ |
subarachnoid, cerebrospinal fluid |
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Cerebrospinal fluid is produced by capillary tufts called: |
choroid plexus |
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Structures that are responsible for reabsorption of CSF back into the blood are known as: |
arachnoid villi |
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List the functions of CSF. |
1-protects the brain by cushioning it, 2-maintain a constant temperature within the cranial cavity, 3-removing waste, 4-increase the buoyancy of the brain so it doesn't crush itself under its own weight |
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a fiber/tract that connects different parts of the same cerebral hemisphere |
association fiber |
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a fiber/tract that connects corresponding parts of both cerebral hemispheres |
commissural fiber |
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the outer layer of an organ just as the brain or kidney |
cortex |
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a place where fibers or pathways cross |
decussation |
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a wider and often deeper groove on the outer surface of the CNS |
fissure |
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collection of nerve cell bodies and unmyelinated fibers within the CNS |
grey matter |
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a ridge on the outer surface of the CNS |
gyrus |
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collection of cell bodies in the CNS |
nucleus |
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a fiber/tract that extends vertically between different levels of CNS |
projection fiber |
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a narrow, shallow groove on the outer surface of the CNS |
sulcus |
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a bundle of myelinated fibers that are all functionally related |
tract |
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myelinated fibers bundled into large tracts within the CNS |
white matter |
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For each of the following CNS structures, determine whether they are composed mostly of gray matter or white matter thalamus |
grey matter |
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For each of the following CNS structures, determine whether they are composed mostly of gray matter or white matter posterior horn |
grey matter |
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For each of the following CNS structures, determine whether they are composed mostly of gray matter or white matter anterior column/funiculus |
white matter |
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For each of the following CNS structures, determine whether they are composed mostly of gray matter or white matter cerebral cortex |
grey matter |
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For each of the following CNS structures, determine whether they are composed mostly of gray matter or white matter corpus callosum |
white matter |
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For each of the following CNS structures, determine whether they are composed mostly of gray matter or white matter basal nuclei |
grey matter |
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For each of the following CNS structures, determine whether they are composed mostly of gray matter or white matter arbor vitae |
white matter |
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separates the frontal lobe from the parietal lobe |
central sulcus |
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separates the temporal lobe from the frontal/parietal lobe |
lateral sulcus |
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divides the two cerebral hemispheres |
longitudinal fissure |
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posterior margin of the frontal lobe |
precentral gyrus |
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anterior margin of the parietal lobe |
postcentral gyrus |
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separates the occipital lobe from the cerebellum |
transverse cerebral fissure |
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part of spinal cord white matter that carries sensory information |
ascending tract |
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cerebral gray matter that smoothes/steadies voluntary movements |
basal nuclei |
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second largest part of brain; balance, posture & coordination |
cerebellum |
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commissural tract connecting right and left cerebral hemispheres |
corpus callosum |
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part of spinal cord white matter that carries motor information |
descending tract |
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where nerve cell bodies of sensory neurons of the PNS reside |
posterior root ganglion |
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part of brain most involved with logic and higher thought |
frontal lobe |
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regulates endocrine system and many homeostatic functions |
hypothalamus |
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controls cardiac, respiratory, vasomotor, and basic reflexes |
medulla oblongata |
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superior brainstem that contains visual and auditory reflex centers |
midbrain |
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contains the primary visual cortex |
occipital lobe |
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primary somatomotor region |
precentral gyrus |
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interconnects different parts of brain; also has respiratory centers |
pons |
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part of brain where we perceive cutaneous sensations |
postcentral gyrus |
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part of brain where loudness, pitch, and sounds are perceived |
temporal lobe |
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the major “sensory relay station” of the brain |
thalamus |
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carries motor impulses away from the CNS |
anterior root |
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Neurons communicate with other neurons and stimulates effector cells which includes both ____________ and __________ |
muscles and glands |
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receptive region of neuron, receives signal from other neurons |
dendrites |
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receptive and integrative region of neuron, main nutritional and metabolic area |
cell body |
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conductive region of a neuron, generates and action potential |
axon |
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Signals from other neurons are received at junctions called _________________, located primarily on the _________________ and _______________, , the receptive and integrative regions of the neuron. |
synapses, cell body, dendrites |
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The area where the axon emerges from the soma is called the ______________. This is also the area where the outgoing signal, called a/an_____________ is generated |
axon hillock, action potential |
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What neuroglia type forms the myelin sheath in the PNS? |
Schwann cell |
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Myelin is found around which part of the neuron? |
axon |
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The tightly wound cell membrane around the axon forms the myelin sheath and acts as |
insulation |
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The gaps between the Schwann cells, called the: |
nodes of ranvier |
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What are essential for the conduction of the action potential. |
nodes of ranvier/myelin sheath gaps |
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The most common central nervous system neuron (structurally) is called a/an _________ neuron. |
multipolar |
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Neurons have (only one or many) axon/axons. |
only one |
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Axons are (never or frequently) branched at their terminal end. |
frequently |
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Dendrites have (only one or many) branch/branches. |
many |
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Channels can be classified as either gated or leak channels. A sodium channel that is always open would be classified as a/an_______ channel. |
leak (nongated) |
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Sodium ions move (into or out of) the neuron through these channels. |
into |
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List the 6 different types of neuroglia and indicate whether thy are part of the central nervous system (CNS) or peripheral nervous system (PNS). |
CNS - astrocytes, microglia, ependymal and oligodendrocytesPNS - satellite cells and Schwann cells |
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Excitable cells, like neurons, are more permeable to ______________than to ________ at rest. |
potassium, sodium |
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Would an increase in the number of passive K+ channels increase or decrease the membrane permeability to K+? |
increase |
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Would opening of voltage-gated K+ channels increase or decrease the membrane permeability to K+? |
increase |
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Would closing the voltage-gated K+ channels increase or decrease the membrane permeability to K+? |
decrease |
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What acts as a chemical force that pushes K+ out of the cell? |
concentration gradient |
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What force tends to pull K+ back into the cell? |
electrical gradient |
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In an excitable cell, also permeable to Na+, the electrochemical gradient would both tend to move Na+ (into or out of) the cell. |
into |
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What compensates for the movement (leakage) of Na+ and K+ ions? |
sodium potassium pump |
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The action potential changes the membrane potential from ______ mV (resting) to ______ mV and back again to the resting membrane potential. |
-70,+30 |
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This results from a change in membrane permeability first to _________ and then to ________ due to the opening of what type of ion channels? |
sodium, potassium, voltage-gated channels |
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What area of the neuron contains the trigger zone, where the action potential is generated? |
axon hillock |
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What areas of the neuron generate signals that open these voltage-gated channels? |
dendrites and cell body |
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Opening of these channels causes the membrane to (voltage change). |
depolarize |
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If the membrane reaches the trigger point, known as ___________, what electrical potential will be generated? |
threshold, action potential |
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What are the two processes that stop the potential from rising above +30 mV? |
inactivation of voltage gated sodium channels, opening of voltage gated potassium channels |
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The opening of voltage-gated K+ channels causes the membrane to |
repolarize |
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Does K+ move into or out of the cell? |
out of |
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If the membrane potential becomes more negative than –70 mV, this is called |
hyperpolarization |
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After an action potential, the neuron cannot generate another action potential because ____________ channels are inactive. This period is called the __________ period. |
sodium, absolute refractory |
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During the ___________ period, the cell can generate another action potential but only if the membrane is (more or less) depolarized. |
relative refractory, more |
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Conduction velocity along the axon is increased by what two characteristics? |
large axon diameter, myelin sheath |
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Conduction along a myelinated axon is called __________ conduction. |
saltatory |
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When many nerve impulses arrive in rapid succession at the synapse between a single stimulatory presynaptic neuron and a postsynaptic neuron, this situation is known as: |
temporal summation |
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When nerve impulses from several presynaptic neurons stimulate a single postsynaptic neuron at the same time it is called: |
spatial summation |
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Sequence of events in terms of what happens at a synapse: |
1. Action potential reaches the axon terminal 2. Voltage-gated Ca+2 channels open allowing Ca+2 to rush into the axon terminal 3. Ca+2 binds to synaptic vescicles, triggering exocytosis of neurotransmitter molecules 4.Neurotransmitter diffuses across the synaptic cleft 5. Neurotransmitter binds to receptors on the postsynaptic membrane 6. Ion channels open, creating a local potential on the postsynaptic membrane |
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What are functions of astrocytes? |
support and brace neurons, Control the chemical environment around neurons |
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Which of the following describes the nervous system sensory function? |
Senses change in the environment |
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Which of the following is not characteristic of neurons? |
They are mitotic |
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Which of the choices below describes the ANS? |
Motor fibers that conduct nerve impulses from the CNS to smooth muscle, cardiac muscle and glands |
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Oligodendrocytes are functionally similar to: |
Schwann cells |
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A neuron that carries impulses away from the CNS to effector organs is an: |
efferent neuron |
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The resting membrane potential is generated by: (select all that apply) |
differences in ionic makeup of ICF and ECF , differences in permeability of the plasma membrane |
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At rest the plasma membrane is more permeable to: |
potassium |
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When the interior of the cell becomes more negative, decreasing the chance of producing a nerve impulse it is called: |
hyperpolarization |
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Which ion channel opens in response to a change in the membrane potential and participates in the generation and conduction of action potentials? |
voltage-gated channels |
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Immediately after an action potential has peaked, which cellular gates open? |
potassium |
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Collections of nerve cell bodies in the central nervous system are called: |
nuclei |
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Which of the following is false or incorrect? An excitatory postsynaptic potential occurs if the excitatory effect is greater than the inhibitory effect but less than the threshold A nerve impulse occurs if the excitatory and inhibitory effects are equal An inhibitory postsynaptic potential occurs if the inhibitory effect is greater than the excitatory, causing hyperpolarization of the membrane |
A nerve impulse occurs if the excitatory and inhibitory effects are equal |
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Saltatory conduction is made possible by: |
myelin sheath |
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What structure is specialized for release and reception of neurotransmitters? Electrical synapse |
chemical synapse |
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What type of membrane potential is generated at the synapse on the postsynaptic membrane? |
local potential |
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When a postsynaptic neuron is stimulated by a large number of terminals at the same time this results in: |
spatial summation |
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The time period when a neuron cannot respond to another stimulus is the: |
absolute refractory period |
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A ridge on the surface of the cortex is called a: |
gyrus |
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Which functional area of the cerebral cortex receives general sensory information from the skin and proprioceptors? |
primary somatosensory cortex |
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Which white matter tracts connect the adjacent areas of the cerebral cortex in the same hemisphere? |
association fibers |
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What structure is described as the main entrance to the cerebral cortex? |
thalamus |
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The connective tissue membranes that cover and protect the central nervous system include: |
pia mater, arachnoid mater, dura mater |
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Which of the following is not a function of the CSF? initiation of some nerve impulses reduction of brain weight protection from blows |
Initiation of some nerve impulses |
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True/False The adult spinal cord ends between L1 and L2. |
true |
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Cell bodies of the sensory neurons of the spinal nerves are located in ________. |
the posterior root ganglia of the spinal cord |
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Most of the ascending and descending pathways to and from the brain cross over from one side of the body to the other, this is called: |
decussation |
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Myelinated and unmyelinated nerve fibers are located in the: |
white matter of the spinal cord |
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After axonal injury, regeneration in peripheral nerves is guided by: |
schwann cells |
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True or False? Posterior and anterior rami are similar in that they both contain sensory and motor fibers. |
true |
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Reflexes that result from practice or repetition are called: |
learned reflexes |
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What connective tissue sheath surrounds the fascicle of a nerve? |
perineurium |
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A major nerve of the sacral plexus is the: |
sciatic nerve |
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Which of the following does not describe the ANS? -a system of motor neurons that innervates smooth and cardiac muscle and glands -general visceral motor system -a system of motor neurons that innervates all muscle cells |
a system of motor neurons that innervates all muscle cells |
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Promoting maintenance activities and conserving body energy is the role of the: |
parasympathetic nervous system |
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Sympathetic nerves may leave the spinal cord at which vertebra? |
first thoracic |
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Cardiovascular effects of the sympathetic division include all except ________. -dilation of the blood vessels serving the skin and digestive viscera -constriction of most blood vessels -increase of heart rate and force |
dilation of the blood vessels serving the skin and digestive viscera |
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Which of the following statements is not true? -Sympathetic division has short preganglionic and long postganglionic fibers; parasympathetic has long preganglionic and short postganglionic fibers. -Sympathetic ganglia are within a few centimeters of the CNS; parasympathetic are close to visceral organs served. -Sympathetic origin is craniosacral; parasympathetic is thoracolumbar. |
Sympathetic origin is craniosacral; parasympathetic is thoracolumbar. |
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The somatic and autonomic nervous systems differ in all of the following except ________. -their effectors -all of the neurotransmitters -their efferent pathways |
all of the neurotransmitters |
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Fibers that enter and leave the sympathetic chain without synapsing form structures called ________. |
splanchnic nerves |
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Visceral reflex arcs differ from somatic in that ________. |
visceral arcs involve two motor neurons |
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In the parasympathetic nervous system preganglionic fibers synapse with postganglionic fibers in: |
terminal ganglia |
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True or false: The rami communicantes are associated only with the sympathetic division of the ANS. |
true |
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True or false: Acetylcholine-releasing fibers are called cholinergic fibers. |
True |
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True or false: The autonomic nervous system may cause activation or inhibition, depending on the division that is active and the target that is affected. |
true |
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A nerve represents the ______ level of biological organization (organelle, cell, tissue, organ, organ system, organism) because virtually all nerves contain all four major types of tissues. |
organ |
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Depending upon its size, a nerve may contain hundreds to tens of thousands of____, plus an even greater number of ________ cells (a type of neuroglia which myelinate axons in the PNS) |
axons, Shwann |
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The connective tissue of a nerve is arranged much like the connective tissue membranes of whole muscle; that is, the entire nerve is surrounded by a layer of connective tissue membrane called the |
epineurium |
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each nerve fascicle within the nerve is surrounded by a(n) |
perineurium |
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individual nerve fibers and their myelin sheaths are surrounded by the |
endoneurium |
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If nervous tissue should become damaged, the amount of repair and regeneration is quite limited, especially for neurons in the ___________. |
central nervous system |
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When injury to the neuron occurs at or close to the ______, the entire cell may die and never regenerate. |
nerve cell body |
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Because the distal portion of the axon is now isolated from the sustaining nerve cell body, the distal end of the axon and its myelin sheath consisting of Schwann cells continue to degenerate, but the cell membrane of the axon and endoneurium generally remain intact. The cellular debris is cleared from the area by |
macrophages |
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Together, the surviving neurilemma and endoneurium with their newly associated myelin sheath become a __________ tube that guides axonal "sprouts" across the injury and towards their site of original contact. |
regeneration |
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Humans have a total of _________ pairs of spinal nerves that emerge from the spinal cord and between adjacent vertebrae. |
31 |
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Number of cervical nerve pairs |
8 |
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Number of thoracic nerve pairs |
12 |
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Number of lumbar nerve pairs |
5 |
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Number of sacral nerve pairs |
5 |
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Number of coccygeal nerve pairs |
1 |
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Cervical spinal nerves are named for their emergence (above or below) their repective vertebrae (except for C8), while all others are named for their emergence (above or below) their respective vertebrae |
above, below |
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Each spinal nerve has a sensory _____ root and motor_______ root |
dorsal, ventral |
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The posterior (dorsal) root has a __________________, which is an enlargememnt where the nerve cell bodies of its neurons reside. |
dorsal root ganglion |
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A short distance from the foramen, the spinal nerve quickly branches to form a ________________, which serves muscles and skin on the back, and a considerable larger _____________. |
posterior ramus, anterior ramus |
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Sets of anterior rami in certain regions along the spinal cord merge partially together as their nerve fibers crisscross and form a _______ |
plexus |
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The ventral rami of C1 through C4 merge to form the ________ plexus. |
cervical |
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The cervical plexus gives rise to the ______ nerve which extends down the neck and thorax to innervate the diaphragm |
phrenic |
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The ventral rami of C5 through C8 and T1 merge to form the _____ plexus. |
brachial |
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Which major nerves branch out from the brachial plexus |
ulnar, radial, median, and musculocutaneous |
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The ______ plexus is formed by a small contribution of fibers from the ventral ramus of T12, bot mostly from L1 through L4. |
lumbar |
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The largest peripheral nerves to emerge from the lumbar plexus, which innervates anterior and medial parts of the thigh, leg, and foot |
femoral nerve |
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The ______ plexus is formed partly by fibers from the ventral ramus of L4, but especially the ventral rami of L5 and S1 through S4. |
sacral |
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The major peripheral nerve that emerges from the sacral plexus |
sciatic nerve |
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Largest nerve in the human body, innervating lateral and posterior thigh, leg, and foot muscles and sensory structures |
sciatic |
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a part of a reflex arc that occurs entirely within the CNS |
interneuron |
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part of a reflex arc that is stimulated by some stimulus |
receptor |
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a muscle or gland's function in reflexes |
effector |
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reflex activity on the same side of the body as the stimulus |
ipsilateral |
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a reflex arc that lacks an interneuron |
monosynaptic |
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reflex activity on the opposite side of the body from the stimulus |
contralateral |
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a simple, rapid, and involuntary/automatic response to a stimulus |
reflex |
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the neuron that sends an impulse to a gland or muscle |
efferent neuron |
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the sensory neuron in a reflex arc |
afferent neuron |
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The motor pathways that innervate smooth or cardiac muscle are known as visceral efferent pathways (collectively, these pathways represent the ___________nervous system.) |
autonomic |
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Virtually all motor pathways of the autonomic nervous system consist of how many motor neurons? |
2 |
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Name the 2 motor neurons |
preganglion fiber, postganglion fiber |
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Generally preganglionic fibers are myelinated and release______ as their neurotransmitter (preganglionic fibers of both sympathetic and parasympathetic pathways) |
ACh |
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Postganglionic fibers are unmyelinated and release either _____ in the case of parasympathetic postganglionic fibers, or ______, in the case of sympathetic postganglionic fibers. |
ACh, norepinephrine |
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Nerve cell bodies of preganglionic fibers are located in__________________ |
gray matter of the brain or spinal cord |
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Nerve cell bodies of postganglionic fibers are located in a(n) ________ located somewhere along the motor pathway |
ganglia |
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general name for an enlargement of a nerve where many nerve cell bodies reside |
ganglia |
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Two divisions of the autonomic nervous system include the _______ nervous system and the _________ division |
parasympathetic, sympathetic |
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rest and digest division of autonomic nervous system |
parasymathetic division |
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fight or flight division of autonomic nervous system |
sympathetic division |
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The __________ division is also known as the thoraco-lumbar division because it is formed by efferent fiber from thoracic (T1 through T12) and upper lumbar (L1 and L2) spinal nerves |
sympathetic |
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The ________ division is known as the cranio-sacral division because it is formed mostly by cranial nerves III, VII, IX, and X, but also S2 throuh S4 spinal nerves |
parasympathetic |