front 1 The subdivisions of the PNS are the [a], [b], and [c]. | back 1 a. somatic
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front 2 The two divisions of the autnomic nervous system are the [a] division and the [b] division | back 2 a. sympathetic
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front 3 At a chemical synapse between two neurons, the neuron receiving the signal is called the presynaptic neuron, and the neuron sending the signal is called the postsynaptic neuron. | back 3 false |
front 4 Neurons in the PNS are always capable of repair while those in the CNS are not. | back 4 false |
front 5 Which of the following statements are TRUE? (1) The sensory function of the nervous system involves sensory receptors sensing certain changes int he internal and external environments. (2) Sensory neurons receive electrical signals from sensory receptors. (3) The integrative function of the nervous system involves analyzing sensory information, storing some of it, and making decisions regarding appropriate responses. (4) Interneurons are located primarily in the PNS. (5) Motor function involves the activation of effectors (muscles and glands) | back 5 A? |
front 6 Which of the following statements are TRUE? (1) The sensory function of the nervous system involves sensory receptors sensing certain changes int he internal and external environments. (2) Sensory neurons receive electrical signals from sensory receptors. (3) The integrative function of the nervous system involves analyzing sensory information, storing some of it, and making decisions regarding appropriate responses. (4) Interneurons are located primarily in the PNS. (5) Motor function involves the activation of effectors (muscles and glands) | back 6 1,2,3,5 |
front 7 A neuron's resting membrane potential is established and maintained by (1) a high concentration of K+ in the extracellular fluid and a high concentration of Na+ in the extracellular fluid. (2) the plasma membrane's higher permeability to Na+ because of the presence of numerous Na+ leakage channels, (3) differences in both ion concnetrations and electrical gradients (4) the fact that there are numeous large, nondiffusible anions int he cytosol, (5) sodium-potassium pumps that help to maintain the proper distribution of sodium and potassium. | back 7 3,4,5 |
front 8 Place the following events in a chemical synapse in the correct order: (1) release of neurotransmitters into the synaptic cleft, (2) arrival of nerve impulse at the presynaptic neuron's synaptic end bulb (or varicosity), (3) either depolarization or hyperpolarization of postsynaptic membrane, (4) inward flow of Ca2+ through activated voltage-gated Ca2+ channels in the synaptic end bulb membrane, (5) exocytosis of synaptic vesicles, (6) opening of ligand-gated channels on the postsynaptic plasma membrane, (7) binding of neurotransmitters to receptors in the postsynaptic neuron's plasma membrane. | back 8 2,4,5,1,7,6,3 |
front 9 Several neurons in the brain sending impulses to a single motor neuron that terminates at a neuromuscular junction is an example of a _________ circuit. | back 9 converging |
front 10 Which of the following statements are true? (1) If the excitatory effect is greater than the inhibitory effect but less than the threshold of stimulation, the result is a subthreshold EPSP. (2) If the excitatory effect is greater than the inhibitory effect and reaches or surpasses the threshold level of stimulation, the result is a threshold or suprathreshold EPSP and one or more nerve impulses. (3) If the inhibitory effect is greater than the excitatory effect, the membrane hyperpolarizes, resulting in inhibition of the postsynaptic neuron and the inability of the neuron to generate a nerve impulse. (4) The greater the summation of hyperpolarizations, the more likely a nerve impulse will be initiated. | back 10 1,2,3 |
front 11 Which of the following statements are true? (1) The basic types of ion channels are gated, leakage, and electrical. (2) Ion channels allow for the development of graded potentials and action poten-tials. (3) The major stimuli that operate gated ion channels are voltage changes, ligands (chemicals), and mechanical stimulation. (4) Ligand-gated channels may open either directly due to the presence of the ligand molecule itself or indirectly through the activation of a “second messenger” by a G protein. (5) A graded potential is useful only for communication over short distances. | back 11 2,3,4,5 |
front 12 Which of the following statements are true? (1) The frequency of impulses and number of activated sensory neurons encodes differences in stimuli intensity. (2) Larger-diameter axons conduct nerve impulses faster than smaller-diameter ones. (3) Continuous conduction is faster than saltatory conduction. (4) The diameter of an axon and the presence or absence of a myelin sheath are the most important factors that determine the speed of nerve impulse propagation. (5) Action potentials are localized, but graded potentials are propagated. | back 12 1,2,4 |
front 13 Neurotransmitters are removed from the synaptic cleft by (1) axonal transport, (2) diffusion away from the cleft, (3) neurosecretory cells, (4) enzymatic breakdown, (5) cellular uptake. | back 13 2,4,5 |
front 14 neurons with just one process extending from the cell body; are always sensory neurons | back 14 unipolar neurons |
front 15 small phagocytic neuroglia | back 15 microglia |
front 16 help maintain an appropriate chemical environment for generation of action potentials by neurons; part of the blood–brain barrier | back 16 astrocytes |
front 17 provide myelin sheath for CNS axons | back 17 oligodendrocytes |
front 18 contains neuronal cell bodies, dendrites, axon terminals, unmyelinated axons and neuroglia | back 18 gray matter |
front 19 a cluster of cell bodies within the CNS | back 19 nucleus |
front 20 form CSF and assist in its circulation; form blood-c erebrospinal barrier | back 20 ependymal cells |
front 21 neurons having several dendrites and one axon; most common neuronal type | back 21 mulitpolar neurons |
front 22 neurons with one main dendrite and one axon; found in the retina of the eye | back 22 bipolar neurons |
front 23 provide myelin sheath for PNS axons | back 23 schwann cells |
front 24 support neurons in PNS ganglia | back 24 satellite cells |
front 25 a cluster of neuronal cell bodies located outside the brain and spinal cord | back 25 ganglia |
front 26 aggregation of myelinated processes from many neurons | back 26 white matter |
front 27 bundles of axons and associated connective tissue and blood vessels lying outside of the CNS | back 27 nerve |
front 28 extensive neuronal networks that help regulate the digestive system | back 28 enteric plexus |
front 29 a sequence of rapidly occurring events that decreases and eventually reverses the membrane potential and then restores it to the resting state; a nerve impulse | back 29 action potential |
front 30 a small deviation from the resting membrane potential that makes the membrane either more or less polarized | back 30 graded potential |
front 31 period of time when a second action potential can be initiated with a very strong stimulus | back 31 relative refractory period |
front 32 the minimum level of depolarization required for a nerve impulse to be generated | back 32 threshold |
front 33 the recovery of the resting membrane potential | back 33 repolarization |
front 34 a neurotransmitter-caused depolarization of the postsynaptic membrane | back 34 excitatory postsynaptic potential |
front 35 a neurotransmitter-caused hyperpolarization of the postsynaptic membrane | back 35 inhibitory postsynaptic potential |
front 36 time during which a neuron cannot produce an action potential even with a very strong stimulus | back 36 absolute refractory period |
front 37 polarization that is less negative than the resting level | back 37 depolarizing graded potential |
front 38 results from the buildup of neurotransmitter released simultaneously by several presynaptic end bulbs | back 38 spatial summation |
front 39 the hyperpolarization that occurs after the repolarizing phase of an action potential | back 39 after-hyperpolarizing phase |
front 40 polarization that is more negative than the resting level | back 40 hyperpolarizing graded potential |
front 41 results from the buildup of neurotransmitter from the rapid, successive release by a single presynaptic end bulb | back 41 temporal summation |
front 42 the part of the neuron that contains the nucleus and organelles | back 42 cell body |
front 43 rough endoplasmic reticulum in neurons; site of protein synthesis | back 43 nissl body |
front 44 store neurotransmitter | back 44 synaptic vesicles |
front 45 the process that propagates nerve impulses toward another neuron, muscle fiber, or gland cell | back 45 axon |
front 46 the highly branched receiving or input portions of a neuron | back 46 dendrites |
front 47 a multilayered lipid and protein covering for axons produced by neuroglia | back 47 myelin sheath |
front 48 the outer nucleated cytoplasmic layer of the Schwann cell | back 48 neurolemma |
front 49 first portion of the axon, closest to the axon hillock | back 49 initial segment |
front 50 site of communication between two neurons or between a neuron and an effector cell | back 50 synapse |
front 51 form the cytoskeleton of a neuron | back 51 neurofibrils |
front 52 gaps in the myelin sheath of an axon | back 52 nodes of Ranvier |
front 53 general term for any neuronal process | back 53 nerve fiber |
front 54 area where the axon joins the cell body | back 54 axon hillock |
front 55 area where nerve impulses arise | back 55 trigger zone |
front 56 the numerous fine processes at the ends of an axon and its collaterals | back 56 axon terminal |
front 57 interstitial fluid-filled space separating two neurons | back 57 synaptic cleft |