Chapter 11 (Nervous System & Tissue)

25 July 2022
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The brain and spinal cord compose the
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Central Nervous System
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Involuntary control of smooth and cardiac muscles and glands is provided by the
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autonomic nervous system
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What is NOT a function of the nervous system?
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direct long-term functions such as growth
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The two anatomical divisions of the nervous system are the:
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central nervous system and peripheral nervous system.
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Upon entering your house, you noticed the smell of cake baking in the oven. What division of the peripheral nervous system is responsible?
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somatic sensory division
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Which nervous system division is responsible for the integration of sensory information?
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central nervous system
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Which of the following is controlled by the somatic motor division?
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Skeletal muscle
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Sarah sensed a mosquito land on her arm and swatted it away with her hand. Which specific PNS division was responsible for the movement of Sarah's hand?
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Somatic motor division
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The sensory, or afferent, division of the peripheral nervous system carries information from the brain and spinal cord to effector organs. (T/F)
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False
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The short, branched cytoplasmic extensions that allow neurons to receive input signals are called
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dendrites
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Neurons that relay information within the CNS and are the location of information processing are called
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interneurons
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Multiple sclerosis is an autoimmune disease that destroys myelin in the CNS. Which of the following would be a symptom of multiple sclerosis?
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delay in neural conduction
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Which of the following is a function of astrocytes?
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facilitate the formation of the blood-brain barrier
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A bundle of axons in the PNS is called
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a nerve
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Dark-staining clusters of RER and ribosomes in neurons are called
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Nissl bodies
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The small phagocytic cells that engulf debris and pathogens in the CNS are the
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microglia
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Determine the direction in which an electrical signal is carried in a typical multipolar neuron.
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dendrites, cell body, axon
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What is the most metabolically active part of a neuron
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cell body
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What specific part of the neuron communicates with a target cell and serves as the secretory region of the cell?
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axon terminals (synaptic knobs)
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What type of neuron is found within the CNS to perform the job of information processing?
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interneurons (association neurons)
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Bundles of axons known as tracts are part of the:
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central nervous system.
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Which neuroglial cell helps form the blood-brain barrier?
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astrocyte
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Ependymal cells:
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circulate cerebrospinal fluid
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Which of the following is an effect of myelination?
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Myelination increases the speed of conduction of action potentials.
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Myelinated axons in the CNS are known as:
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white matter.
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Neurons are responsible for sending and receiving signals referred to as action potentials while neuroglial cells serve a variety of supportive functions. (T/F)
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True
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Bipolar neurons have one axon and one dendrite. (T/F)
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True
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The conduction of an action potential is faster in unmyelinated axons than in myelinated axons. (T/F)
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False
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The Na+/K+ pump moves
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Na+ out of and K+ into the cell
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Which of the following causes the hyperpolarization phase of an action potential?
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K+ outflow via voltage-gated potassium ion channels
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Tetrodotoxin is a toxin that blocks voltage-gated sodium ion channels. What effect would this have on the function of neurons?
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The neuron would be unable to generate action potentials.
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The type of action potential propagation in which action potentials are only generated at nodes of Ranvier is called
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saltatory conduction
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If a stimulus opens ligand-gated sodium ion channels, the neuron will
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depolarize
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Conduction speed will be fastest in a
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Large myelinated axons
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If we compare an axon to an insulated copper wire going to a light bulb, then myelin would be
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the insulation
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Which of the following is the primary factor in the maintenance of a negative charge during resting membrane potential?
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leak channels
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What type of ion channels is always open?
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leak
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The influx of positive charges makes the membrane potential more positive and is known as:
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depolarization.
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A series of measurements with a voltmeter show a neuron's membrane potential becoming more negative, from -70 mV to -85 mV. This neuron is experiencing a:
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hyperpolarization phase.
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What is more likely to promote an action potential?
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depolarization
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Which statement best describes the all-or-none principle?
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An action potential happens completely, or it doesn't happen at all
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What membrane potential must generally be met in order to achieve threshold?
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-55 mV
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Which of the following is correct about threshold?
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Threshold is more positive than the resting potential.
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During repolarization of a neuron:
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potassium ions move out of the cell.
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Voltage-gated sodium channels have both an activation gate and:
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an inactivation gate.
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Place these steps of the action potential in the correct order. 1. Sodium ions channels return to the resting state and repolarization continues. 2. Voltage-gated sodium ion channels activate, sodium ions enter, and the axon section depolarizes. 3. As potassium ion channels return to resting state, the axolemma may hyperpolarize before returning to the resting membrane potential. 4. A local potential depolarizes the axolemma of the trigger zone to threshold. 5. Sodium ion channels inactivate, and voltage-gated potassium ion channels activate, so sodium ions stop entering and potassium ions leave, beginning repolarization.
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4, 2, 5, 1, 3
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Voltage-gated sodium channels are activated:
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only if the cell is depolarized to threshold.
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During saltatory conduction, action potentials are generated:
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only at nodes of Ranvier of myelinated axons.
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Determine the fiber type in which propagation of an action potential will occur most quickly.
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myelinated type A fiber
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Which type of fiber has the largest diameter?
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type a
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During depolarization, the membrane potential becomes more positive. (T/F)
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true
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Which of the following is one of the mechanisms for termination of synaptic transmission?
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degradation of neurotransmitter by enzyme
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An EPSP will
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bring the neuron closer to threshold
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Simultaneous stimulation from multiple presynaptic neurons will result in
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spatial summation
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A neuron that receives neurotransmitters from another neuron is called:
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the postsynaptic neuron.
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What is NOT associated with a chemical synapse?
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gap junction
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What type of synapse must have receptors to transmit signals?
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chemical synapse
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What ion triggers synaptic vesicles to release neurotransmitters into the synaptic cleft?
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calcium
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If the receptor site for a neurotransmitter were completely blocked:
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synaptic transmission would fail.
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Which of the following is most likely to produce an action potential?
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excitatory postsynaptic potential (EPSP)
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What would most likely lead to an IPSP?
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opening of potassium ion channels
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A local hyperpolarization that changes a postsynaptic neuron's membrane from resting potential to -85 mV is:
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an inhibitory postsynaptic potential (IPSP)
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Which of the following would NOT terminate the effects of the neurotransmitter?
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presence of calcium ions in the presynaptic neuron
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A neurotransmitter may have an excitatory or an inhibitory effect on the postsynaptic cell, depending on
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the receptor to which it binds
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The neurotransmitter involved in emotion, motivation, and addictive behavior is
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dopamine
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Which of the following neurotransmitters is always inhibitory?
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GABA
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Cholinergic synapses use the neurotransmitter:
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acetylcholine.
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A network of neurons that perform a common function is called
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neural pool