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13 Cards in this Set
- Front
- Back
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Neurons communicate using _______ communication. ________ communication occurs via ion exchange and the generation of membrane potentials down the length of the axon. ________ communication occurs via neurotransmitter release from the presynaptic cell and the binding of these neurotransmitters to the postsynaptic cell. |
electrical and chemical electrical chemical |
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Neurons consist of many different parts. ________ are appendages that receive signals from other cells. The ________ is the location of the nucleus as well as organelles such as the endoplasmic reticulum and ribosomes. The _______ is where the cell body transitions to the axon, and where action potentials are initiated. The _______ is a long appendage down which an action potential travels. The ________ is the end of the axon from which neurotransmitters are released. ________ are exposed areas of myelinated axons that permit saltatory conduction. The _______ consists of the nerve terminal of the presynaptic neuron, the membrane of the postsynaptic cells, and the space between the two, called the _______. |
dendrites cell body or soma axon hillock axon nerve terminal or synaptic bouton Nodes of Ranvier synapse synaptic cleft |
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Many axons are coated in _______, an insulating substance that prevents signal loss. It is created by _______ in the central nervous system and _______ in the peripheral nervous system. It prevents dissipation of neural impulse and crossing of neural impulses from adjacent neurons. |
myelin oligodendrocytes Schwann cells |
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Individual axons are bundled into _______ in the peripheral nervous system and ________ in the central nervous system. A single _______ may carry multiple types of information, including sensory, motor or both. _______ contain only one type of information. Cell bodies of neurons of the same type within a nerve cluster in _______ in the peripheral nervous system. Cell bodies of the individual neurons within a tract cluster in _______ in the central nervous system. |
nerves tracts nerve tracts ganglia nuclei |
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________ are other cells within the nervous system in addition to neurons. ________ nourish neurons and form the blood-brain barrier, which controls the transmission of solutes from the bloodstream into nervous tissue. ________ line the ventricles of the brain and produce cerebrospinal fluid, which physically supports the brain and serves as a shock absorber. ________ are phagocytic cells that ingest and break down waste products and pathogens in the central nervous system. ________ produce myelin around axons. |
neuroglia or glial cells astrocytes ependymal cells microglia oligodendrocytes (CNS) and Schwann cells (PNS) |
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All neurons exhibit a _______ of approximately -70 mV. It is maintained using selective permeability of ions as the ________. It pumps ________ ions out of the cell for every ________ ions pumped in. |
resting membrane potential Na+/K+ ATPase 3 sodium (Na+) 2 potassium (K+) |
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Incoming signals can be either excitatory or inhibitory. Excitatory signals cause _______ of the neuron. Inhibitory signals cause _______ of the neuron. ________ refers to the addition of multiple signals near each other in time. ________ refers to the addition of multiple signals near each other in space. |
depolarization hyperpolarization temporal summation spatial summation |
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An ________ is used to propagate signals down the axon. When enough excitatory stimulation occurs, the cell is depolarized to the _______ and _______ open. _______ flows into the neuron due to its strong _______. This continues depolarizing the neuron. At the peak of the action potential (approximately +35 mV), _______ are inactivated and ________ open. _______ flows out of the neuron due to its strong _______, repolarizing the cell. _______ stay open long enough to overshoot the action potential, resulting in a _______ neuron; then the ______ close. The ________ brings the neuron back to the resting potential and restores the sodium and potassium gradients. While the axon is hyperpolarized, it is in its _______. During the ________, the cell is unable to fire another action potential. During the ________, the cell requires a larger than normal stimulus to fire an action potential. The impulse propagates down the length of the axon because the influx of sodium in one segment of the axon brings the subsequent segment of the axon to threshold. The fact that the preceding segment of the axon is in its refractory period means that the action potential can only travel in one direction. |
action potential threshold voltage voltage-gated sodium channels sodium electrochemical gradient sodium channels potassium channels potassium electrochemical gradient potassium channels hyperpolarized potassium channels Na+/K+ ATPase refractory period absolute refractory period relative refractory period |
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At the nerve terminal, neurotransmitters are released into the synapse. When the action potential arrives at the nerve terminal, ________ open. The influx of ________ causes fusion of vesicles filled with neurotransmitter with the presynaptic membrane, resulting in exocytosis of neurotransmitter into the synaptic cleft. The neurotransmitters bind to receptors on the postsynaptic cell, which may be ________. |
voltage-gated calcium channels calcium ligand-gated ion channels or G protein-coupled receptors |
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Neurotransmitters must be cleared from the postsynaptic receptors to stop the propagation of the signal. What are the three ways this can happen? |
1. broken down by enzymes 2. reuptake channels 3. diffuse out of synaptic cleft |
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What are the three types of neurons in the nervous system? |
motor (efferent) neurons interneurons sensory (afferent) neurons |
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The nervous system is made up of the ______. In the CNS, _______ consists of myelinated axons, and _______ consists of unmyelinated cell bodies and dendrites. In the brain, _______ is deeper than ______. In the spinal cord, ______ is deeper than ______. The PNS is divided into the _______. The _______ nervous system is further divided into the _______. |
central nervous system (brain and spinal cord) peripheral nervous system (cranial and spinal nerves) white matter grey matter white matter grey matter grey matter white matter somatic (voluntary) and autonomic (automatic) nervous systems parasympathetic (rest-and-digest) and sympathetic (fight-or-flight) branches |
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_______ use the ability of interneurons in the spinal cord to relay information to the source of stimuli while simultaneously routing it to the brain. In a _______, the sensory (afferent, presynaptic) neuron fires directly onto the motor (efferent, postsynaptic) neuron. In a _______, the sensory neuron may fire onto a motor neuron as well as interneurons that fire onto other motor neurons. |
reflex arcs monosynaptic reflex arc polysynaptic reflex arc |
