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86 Cards in this Set
- Front
- Back
A grouping of cell bodies located within the central nervous system is known as ________
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ganglion
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The numerous small extensions from the soma are known as the __________.
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dendrites
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A _____ neuron transmits impulses from the CNS to the PNS.
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motor
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An association neuron is located entirely within the _____ nervous system.
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central
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Voluntary effectors (skeletal muscle) are innervated by _____motor neurons.
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somatic
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Sensory neurons (or afferent neurons) transmits impulses from the _____ to the _____ nervous system
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periphery to the central
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Myelin sheaths around axons located within the CNS (central nervous system) are formed by ______________.
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oligodendrocytes
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_______ form myelin sheaths around axons in the PNS
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Schwann cells
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______ migrate throughout the CNS and phagocytize foreign and degenerated material.
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Microglia
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_____ help to regulate the external environment of neurons in the CNS.
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Astrocytes
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Which is not a supporting cell or glial cell of the nervous system? A) Schwann cell, B) oligodendrocyte, C) ependymal cells, or D) assoc. neurons
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association neuron is a type of neuron not a type of glial cell.
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Arrange these action potential events in their proper sequence:
1. threshold voltage is reached 2. K+ gates begin to open 3. K+ gates close 4. Na+ gates begin to open 5. Na+ gates begin to close 6. membrane repolarization begins. |
D) 1,4,2,5,6,3
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The diffusion of K+ out of cell makes the inside of cell less positive,(or more negative), & acts to restore original resting mb pot. This process is called _____________.
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repolarization
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Nerve impulses are conducted along an axon without decrement. This means the action potentials are conducted without ____________.
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decreasing amplitude
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A __________ is a synapse between a somatic motor neuron and a skeletal muscle fiber.
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neuromuscular junction
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______ synapses require the presence of gap junctions
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electrical
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_______ are water-filled channels through which ions can pass from one cell to another permitting impulses to be conducted directly from one cell to another
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Gap junctions
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Acetylcholinesterase is an enzyme located on or immediately outside the _________.
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postsynaptic mb
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does the AP produced at the last region of the axon have the same amplitude as the AP at the first region of the axon?
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yes
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The 1st voltage-regulated gates encountered along the neuron mb, which initiate formation of action pot., are located on the neuron near the _______________.
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axon hillock
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Cocaine stimulates the synapses of specific neurons that release dopamine & other monoamines, by ______________.
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blocking the dopamine or monoamine reuptake into the presynaptic axon ending
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The central nervous system (CNS) includes the brain and _____
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spinal cord
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______ are the functional units of the nervous system by which they initiate, conduct, & transmit nerve impulses.
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Neurons
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_______ cells are supporting cells for the neurons.
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neuroglia
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Can a nerve contain both sensory and motor neurons?
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yes, a mixed nerve
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Capillaries in the brain are joined together by ______. This helps to form the BBB.
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tight junctions
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A(An) ________ neuron transmits impulses from the PNS to the CNS.
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sensory
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Involuntary effectors (glands, smooth or cardiac muscle) are innervated by _________neurons.
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autonomic neurons
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Afferent pathways are __(motor/sensory)__ & transmit impulses _(to/from)__ the CNS
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sensory, to
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what is the morphological difference betw. grey matter & white matter?
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gray-cell bodies & dendrites Vs white-myelinated axons
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which would contain the highest density of voltage gated Na+ channels? A) dendrites, B) soma C) nodes of Ranvier D) internodes E) synaptic end bulbs
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C) nodes of Ranvier
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what is the major extracellular cation?
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Na+
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An IPSP is _(hyperpolarization /repolorization/ depolarization?)___ of the postsynaptic neuron.
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hyperpolorization
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Saltatory conduct occurs only in ________
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myelinated nerve fibers
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neurons communicate specifically through chemicals called _______
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neurotransmitters
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explain how one way transmission of signal conduction is insured on an axon:
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absolute refractory period
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which glial cell forms a myelin sheath in the PNS?
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schwann cells
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which glial cell forms a myelin sheath in the CNS?
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ogliodendrocytes
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which glial cells remove pathogens & cell debris from phagocytosis?
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mircroglia
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which glial cells form the BBB?
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astrocytes
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what is 1 essential difference betwe the Somatic motor & the Autonomic motor?
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somatic- voluntary VS autonomic- involuntary
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what will occur when a neuron is depolarized to threashold?
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voltage-gated Na+ channels open
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what is a nerve?
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bundle of axons-PNS
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what are the cells of the PNS?
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satellite & schwann
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what is the function of satellite cells?
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support ganglia cell bodies in PNS
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what is the function of schwann cells?
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form myelin sheath successive wrapping of cmb- PNS
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how many axons do schwann cell wrap around?
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1 axon only
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what is neurilemma?
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continuous sheath of schwann cells- surrounds axon- can be myelinated or unmyelinated
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where can neurilemma be found?
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PNS only
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is neurilemma myelinated or unmyelinated?
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can be either
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___unmyelinated? /myelinated?___ usually have small axons
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unmyelinated
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myelinated vs unmyelinated, which are faster?
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myelinated
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what supporting cell in PNS has the ability to regenerate?
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schwann
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which cell has limited ability to regenerate in CNS?
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oligodendrocyte
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what must be intact for axon to regenerate in schwann cell?
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cmb
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what are the 4 supporting cells (glia) of the CNS?
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Oligodendrocytes, Microglia, Astrocytes, Ependymal
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where is the gray matter in the brain located?
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cell bodies & dendrites
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when does CNS myelination occur in the human body?
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post natally
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how many axons do oligrodendrites myelinate?
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several
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what is the white matter in the brain?
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myelinated axons CNS
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can axons repair in CNS?
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limited- oligodendrites: 1.inhibitory proteins (myelination) 2. glial scar
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what is the effect of a glial scar?
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physically blocks oligodendrites from repairing axon & induces inhibitory proteins
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what is the beneficial function of microglia?
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they are resident macrophages- secrete antiinflammatory (brain)
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what are the implications of microglia?
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overactivity can cause neurodegeneration
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what are the end feet?
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astrocytes
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what are 3 functions of neurons?
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responsive, conductivity, secretory
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can neurons divide?
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not regularly, most are postmitotic & G0
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can glia divide?
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yes, considered mitotic, but limited
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what are the predominant cells in the nervous sys?
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supporting cells (glia/glial) outnumber neurons 5:1
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a neuron is composed of ____
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cb, axon, & dendrites
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what is the nutrition center?
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cb of neuron where macromolecules are produced
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where are the nissl bodies & nucleus contained?
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cb
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what are gliomas?
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mitotic glia cells produce brain tumor
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what are nissl bodies?
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in cb, have RER for syn of mb proteins
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collection of cell bodies within CNS is called _____
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nuclei (not to be mistaken for nucleus)
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collection of cb outside CNS is called ______
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ganglia (basil ganglia-nuclei in brain)
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what are the receptive processes?
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dendrites
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what are the functions of axons?
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conduct impulse
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where is the origination of impulse?
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axon hillock
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what are axon collaterals?
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branchings located on some axons
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how long are axons?
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mm-m
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what is the BBB?
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capillaries to brain not porous, tight junctions, selective barrier
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how is molecule transport conducted to and from brain? (4)
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diffusion, active trans, endocytosis, & exocytosis
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through BBB __para/transcellular?__ is perdominant
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transcellular predominant.....paracellular is restricted
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what can pass the BBB easy?
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lipid soluble mo, O2, CO2, alcohol, barbiturates
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how are ions & polar mo transported through BBB?
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channels or transporters, GLUT1
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