A) Subthreshold stimulusB) Temporal summationC) Spatial Saltatory conduction is made possible by ________. The LibreTexts libraries arePowered by NICE CXone Expertand are supported by the Department of Education Open Textbook Pilot Project, the UC Davis Office of the Provost, the UC Davis Library, the California State University Affordable Learning Solutions Program, and Merlot. As the flow of current in a wire occurs at a specific voltage only, similarly the conduction of nerve impulse occurs when a stimulus has a maximum threshold value of -55 millivolts. True or false: The all-or-none phenomenon as applied to nerve The nerve impulse travels across the membrane of the axon in the form of an electrical signal. What are ciliated CNS neuroglia that play an active role in moving the cerebrospinal fluid called? True or False, In myelinated axons the voltage-regulated sodium channels are concentrated at the nodes of Ranvier. ________.A) astrocytes B) microglia C) Schwann cells D) oligodendrocytes. True or False, The oligodendrocytes can myelinate several axons. If a membrane depolarization does not reach the threshold level, an action potential will not happen. A second nerve impulse cannot be generated until _____. You can specify conditions of storing and accessing cookies in your browser, A second nerve impulse cannot be generated until ________. Postsynaptic membrane. cord and sensory ganglia of cranial nerves? B) Current is directly proportional to the voltage. A teacher walks into the Classroom and says If only Yesterday was Tomorrow Today would have been a Saturday Which Day did the Teacher make this Statement? This amazing cloud-to-surface lightning occurred when a difference in electrical charge built up in a cloud relative to the ground. Following the entrance of Ca2+ is the release of neurotransmitter. Both of the ion channels then close, and the sodium-potassium pump restores the resting potential of -70 mV. The fastest conduction velocity occurs in the largest diameter nerve fibres. a. A) the myelin sheath )Which neuron is a sensory neuron found in a reflex arc? A second nerve impulse cannot be generated until ________. A second nerve impulse cannot be generated until: the refractory period: In what way does the interior surface of a cell membrane of a resting (nonconducting) neuron differ from the external environment? Plasma membrane exhibits voltage-gated Na+ and K+ channels. Any distraction in this process can have drastic effects on the body. At the threshold, voltage-dependent sodium channels become fully activated, and Na+ pours into the cell. If the temperature is higher, the rate of diffusion of sodium and potassium ions will be high and axon will become depolarized quickly which will cause a faster nerve impulse conduction. Absolute refractory period The interior of the cell becomes less negative due to an influx of sodium ions. This delay may be accounted for by three factors. The role of acetylcholinesterase is to ________. Immediately after an action potential has peaked, which cellular gates open? Axon diameter and degree of myelination determine nerve impulse Legal. Nerve cell adhesion molecules (N-CAMs) ________. analyzes sensory information, stores information, makes decisions. In conducting nerve impulse, the following play a major role: Axon plays a major role in the process by transmitting signals in the form of nerve impulses via synapses to the target cells. After neurotransmitter is released from the presynaptic terminal, it diffuses across the synaptic cleft and binds to receptor proteins on the postsynaptic membrane. Axon- Helps in the propagation of nerve impulses to the target cell. be generated until ________. Once the membrane potential is completely returned to its resting potential (when membrane potential is reestablished), the neurons become ready for second or next nerve stimulus. B) stimulate the production of acetylcholine, C) destroy ACh a brief period after its release by the axon endings. mimicked by morphine, heroin, and methadone?A) acetylcholine B) The part of a neuron that conducts impulses away from its cell body is called a(n) ________. True or False, Strong stimuli cause the amplitude of action potentials generated to increase. Unmyelinated axons do not have nodes of Ranvier, and ion channels in these axons are spread over the entire membrane surface. c) ependymal cells In electrical transmission, the ionic current flows directly through channels that couple the cells. the membrane potential has been reestablished. B) called neuroglial cells Determine its coordinate direction angles of the force. Which of the following is false or incorrect? This process requires ATP because the movement of ions is against the concentration gradient of both ions. Once an action potential has been generated at the axon hillock, it is conducted along the length of the axon until it reaches the terminals, the fingerlike extensions of the neuron that are next to other neurons and muscle cells (see the section The nerve cell: The neuron). True or False, Neurons in the CNS are organized into functional groups. In contrast to electrical transmission, which takes place with almost no delay, chemical transmission exhibits synaptic delay. Explain how an electrical signal in a presynaptic neuron causes the transmission of a chemical signal at the synapse. Calcium ions. This is called the absolute refractory period, and it is followed by a relative refractory period, during which another action potential can be generated, but only by a greater stimulus current than that originally needed. b) postsynaptic potential C) Specific sodium gates will open. answer choices Which of the following will occur when an excitatory postsynaptic B) A nerve impulse occurs if the excitatory and inhibitory effects are equal. 3.) Nerve impulse propagates by jumping from one node of Ranvier to the next. Na+ channels open: . b) ligand-gated channel A single type of channel will open, permitting simultaneous flow of sodium and potassium. 0.50.50.5 liters Which of the following is not a function of astrocytes? repolarization occurs with the flow of K+ out of the cell. A neural circuit in which a single impulse is transmitted over and over is a ________. They are generated when the nerve Almost instantly the membrane actually reverses polarity, and the inside acquires a positive charge in relation to the outside. Therefore, repolarization helps in maintaining or restoring the original membrane potential state. d) act as a transmitting agent, destroy ACh a brief period after its release by the axon endings, Which of the following is false or incorrect? contraction would occur, D) the impulse would spread bidirectionally. d) leakage channel, What is the role of acetylcholinesterase? Because it varies in amplitude, the local potential is said to be graded. The neurons are said to be in resting phase when there is no nerve impulse. a) the synaptic cleft prevents an impulse from being transmitted directly from one neuron to another Receives stimuli. The first factor is the outside diameter of the nerve fibre. This phenomenon has formed the basis for classifying mammalian nerve fibres into groups in order of decreasing diameter and decreasing conduction velocity. Another factor is the temperature of the nerve fibre. When information is delivered within the CNS simultaneously by different parts of the neural pathway, the process is called ________ processing. The number of channels utilized in saltatory conduction is less than continuous conduction due to which delay of nerve impulse does not occur. An (Do not expand to minterm form before plotting.) B) the impulse would spread bidirectionally. A neuron that has as its primary function the job of connecting other neurons is called a(n) _____. ________ law is the relationship between voltage, current, and resistance. Following sodium inactivation is the opening of potassium channels, which allows the diffusion of K+ out of the cell. ________ is a disease that gradually destroys the myelin sheaths of neurons in the CNS, particularly in young adults. Which of the following is not characteristic of neurons? 6.) Similarly, in the case of nerve impulse conduction, the neurons the stimulus must have a threshold value for causing the movement of ions across the length of axon (for conducting nerve impulse) by opening the voltage-gated ion channels. A Plasma membrane exhibits voltage-gated Ca2+ channels. about midpoint along the length of the axon ________.A) the Saltatory conduction increases the speed at which a nerve signal is conducted down the length of an axon. Which of the following would be the most typical urinary output in a day? It persists for only 2 milliseconds. This is essential for altering the resting membrane state to action membrane potential. will result in no response in a neuron. Other neurons have True or False, A stimulus traveling toward a synapse appears to open calcium channels at the presynaptic end, which in turn promotes fusion of synaptic vesicles to the axonal membrane. It is a change in the resting state of the neuron. A second nerve impulse cannot be generated until ________. membrane exhibits chemically gated ion channels. During depolarization, as impulse is carried across the cell, sodium ions channels open and the sodium outside of the cell enters the cell. The place where an axon terminal meets another cell is called a synapse. C) control the chemical environment around neurons, D) guide the migration of young neurons, synapse formation, and Collections of nerve cell bodies outside the central nervous system A second nerve impulse cannot be generated until _____. The cell that sends the nerve impulse is called the presynaptic cell, and the cell that receives the nerve impulse is called the postsynaptic cell. The part of the neuron that normally receives stimuli is called ________. serotonin C) nitric oxide D) endorphin, A neuron that has as its primary function the job of connecting other a stimulus? Which of the following is not true of graded potentials? The period after an initial stimulus when a neuron is not sensitive to another stimulus is the ________. This is due to a clustering of Na+ and K+ ion channels at the Nodes of Ranvier. Researchers call the nerve impulse an all-or-none reaction since there are no gradations between threshold potential and fully activated potential. It is thus a mode of communication between different cells. Ciliated CNS neuroglia that play an active role in moving the cerebrospinal fluid are called ________. 5) Different types of sensory input can have Transmission takes place through gap junctions, which are protein channels that link the cellular contents of adjacent neurons. a) sodium gates in the membrane can open in response to electrical potential changes The sodium-potassium pump moves both ions from areas of lower to higher concentration, using energy in ATP and carrier proteins in the cell membrane. other types of channels and can fire multiple action potentials to This series of activations, by propagating the action potential along the fibre with virtually no reduction in amplitude . Ca2+ is known to be sequestered by certain organelles within the terminal, including the endoplasmic reticulum. Which of the following will occur when an excitatory postsynaptic potential (EPSP) is being generated on the dendritic membrane? A) The release of neurotransmitter molecules gives cells the a) nuclei The action potential is a result of the movement of ions in and out of the cell. ________ is a neurotransmitter of the CNS that is used by Purkinje cells of the CNS. d. 2.22.22.2 liters. A neuronal circuit that concentrates or directs a large number of incoming impulses to a rather small number of neurons is called a(n) ________. 2.) The all-or-none phenomenon as applied to nerve conduction states that the whole nerve cell must be stimulated for conduction to take place. Study now. 2.) Polarization is the situation in which the membrane is electrically charged but non-conductive. Which of the following describes the nervous system integrative function? Owning to the importance of this discovery, he was awarded Noble Prize in 1932. b) amplify or enhance the effect of ACh A second nerve impulse cannot be generated until ________. A nerve impulse is a wave of electrochemical changes that travel across the plasma membrane and helps in the generation of an action potential. Accessibility StatementFor more information contact us atinfo@libretexts.orgor check out our status page at https://status.libretexts.org. B) destroy ACh a brief period after its release by the axonal endings. There the vesicles lose their coats, are probably refilled with neurotransmitter, and pinch off from the cisternae to become synaptic vesicles once more. D) Some ions are prevented from moving down their concentration gradients by ATP-driven pumps. Which of these ions is actively transported through the cell membrane to establish a resting potential? Some synapses are purely electrical and make direct electrical connections between neurons. B) the membrane potential has been reestablished, C) the Na ions have been pumped back into the cell, In what way does the interior surface of a cell membrane of a resting An inhibitory postsynaptic potential (IPSP) is associated with ________. Nerve Impulse is defined as a wave of electrical chemical changes across the neuron that helps in the generation of the action potential in response to the stimulus. That is, the membrane potential has to reach a certain level of depolarization, called the threshold, otherwise, an action potential will not start. B) destroy ACh a brief period after its release by the axon endings. a single depolarization. The refractory phase is a brief period after the successful transmission of a nerve impulse. The neuron is either at rest with a polarized membrane, or it is conducting a nerve impulse at reverse polarization. True or False, A synapse formed between the axon ending of one neuron and the cell body of another neuron is called an axosomatic synapse. This process is called repolarization. At a chemical synapse, both the presynaptic and postsynaptic areas of the cells are full of the molecular machinery that is involved in the transmission of nerve impulses. Thus, no sodium ions will move inside the membrane. The transmission of nerve impulses across chemical synapses is more complex. impulse would move to the axon terminal only, C) the impulse would move to the axon terminal only, and the muscle returned it's base level or even more negative. What major ion currents occur at the point along the action potential Which of the following is correct relative to Ohm's law? Definition. However, most synapses are chemical synapses. Which of the following will occur when an excitatory postsynaptic potential (EPSP) is being generated on the dendritic membrane? Vesicle membranes are then recovered from the plasma membrane through endocytosis. Due to this, the transmission of nerve impulses is slower than electrical synapses.
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