After repolarization there is a period during which a second action potential cannot be initiated, no matter how large a stimulus current is applied to the neuron. Like the receptor potential, the PSP is a graded response, varying in amplitude according to the duration and amount of stimulation by neurotransmitters. A nerve impulse is thus an important signal transduction mode for triggering a response in major body parts due to a strong stimulus. the amplitude of action potentials generated to increase. 4.) Which of the following will occur when an excitatory postsynaptic The process of transmission of a nerve impulse from one neuron to the other, after reaching the axons synaptic terminal, is known as synapses. outside the central nervous system, Myelination of the nerve fibers in the central nervous system is the Figure \(\PageIndex{3}\)shows in greater detail how the sodium-potassium pump works. Which of the following is correct relative to Ohm's law? Synaptic cleft. Nerve impulse was discovered by British Scientist Lord Adrian in the 1930s. Figure 11.4. Which of the following is true about the movement of ions across excitable living membranes? What is certain is that when the concentration of Ca2+ is increased within the terminal, the probability of transmitter release is also increased. This delay may be accounted for by three factors. Strong stimuli cause the amplitude of action potentials generated to increase. C) The synaptic cleft prevents an impulse from being transmitted When the buildup of charge was great enough, a sudden discharge of electricity occurred. 50. Particularly the ions included in this process are sodium and potassium ions. 2.) d) moves membrane potential away from threshold, Collections of nerve cell bodies outside the central nervous system are called ________. The EPP is actually made up of multiple MEPPs, which arise when an activated terminal releases hundreds of neurotransmitter quanta. Calcium causes synaptic vesicles to fuse with the membrane, releasing their contents into the narrow space between the presynaptic and postsynaptic membranes. During this period, the membrane prepares itself for the conduction of the second stimulus after restoring the original resting state. B) A nerve impulse occurs if the excitatory and inhibitory effects are equal. serotonin C) nitric oxide D) endorphin, A neuron that has as its primary function the job of connecting other Select the correct statement about serial processing. The action potential travels along the entire length of the axon. True or False, Cell bodies of sensory neurons may be located in ganglia lying outside the central nervous system. (nonconducting) neuron differ from the external environment? a) nuclei 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. 1.) Which of the following will occur when an excitatory postsynaptic potential (EPSP) is being generated on the dendritic membrane? . There the vesicles lose their coats, are probably refilled with neurotransmitter, and pinch off from the cisternae to become synaptic vesicles once more. Nerve impulse can be defined as a signal that transmits along the nerve fibers. Saltatory conduction is made possible by ________. 4.) In this situation, sodium channels open and potassium channels are closed. The interior is ________. This reverse polarity constitutes the nerve impulse. 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. The combined effect of sodium inactivation, which blocks the influx of cations, and potassium activation, which causes the efflux of other cations, is the immediate return of the cell membrane to a polarized state, with the inside negative in relation to the outside. Which of the following is not a function of astrocytes? the interior is _____. During polarization, the membrane is in a resting potential state. ________ law is the relationship between voltage, current, and resistance. The term central nervous system refers to the ________. c) short distance hyperpolarization frequency of action potentials Researchers call the nerve impulse an all-or-none reaction since there are no gradations between threshold potential and fully activated potential. the Na+ ions have been pumped back into the cell. Neurons are a complex network of fibers that transmit information from the axon ending of one neuron to the dendrite of another neuron. Third, they are metabolized into inactive compounds by enzymes in the synaptic cleft. See answer (1) Copy. The part of a neuron that conducts impulses away from its cell body is called a(n) ________. D) Group C fibers are not capable of saltatory conduction. A single type of channel will open, permitting simultaneous flow of This reverse polarity constitutes the nerve impulse. How does this difference in electrical charge come about? Second, the response of the postsynaptic receptor takes about 0.15 millisecond. The answer involves ions, which are electrically charged atoms or molecules. The resulting increase in positive charge inside the cell (up to about +40 mV) starts the action potential. 5.) For the following, indicate if the number of half-lives elapsed is: Nerve cell adhesion molecules (N-CAMs) ________. A series of nerve impulses arriving in rapid succession at the axon terminal is accurately reproduced as a series in the postsynaptic cell because the quanta of neurotransmitter released by each impulse are inactivated as soon as they stimulate the receptor proteins. Both of the ion channels then close, and the sodium-potassium pump restores the resting potential of -70 mV. Ciliated CNS neuroglia that play an active role in moving the cerebrospinal fluid are called ________. Legal. A second nerve impulse cannot be generated until ________. Which neuron is common only in dorsal root ganglia of the spinal Select the correct statement regarding synapses. Stimulation of a B) Neurotransmitter receptors are located on the axons terminals of cells. Signup as a free member below and you'll be brought back to this page to try the sample materials before you buy. Neuroglia that control the chemical environment around neurons by buffering potassium and recapturing neurotransmitters are ________. True or False, Neurons in the CNS are organized into functional groups. c) stimulate the production of acetylcholine d. 2.22.22.2 liters. In what way does the interior surface of a cell membrane of a resting (nonconducting) neuron differ from the external environment? 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. The action potential state is based on the All or none method and has two possibilities: If the stimulus is not more than the threshold value, then there will be no action potential state across the length of the axon. 38. phase labeled D? True or False, Enkephalins and endorphins are peptides that act like morphine. The rate of transmission and generation of nerve impulses depends upon the type of cell. Axon terminals release neurotransmitters. The As is stated above, the lipid bilayer of the neuronal membrane tends to repel electrically charged, hydrated ions, making virtually impossible the movement across the membrane that is necessary for the generation of nerve impulses. 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. A neuron that has as its primary function the job of connecting other neurons is called a(n) ________. the membrane potential has been reestablished. It is a change in the resting state of the neuron. In myelinated neurons, ion flows occur only at the nodes of Ranvier. 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. True or False, Saltatory conduction occurs because of the presence of salt (NaCl) around the neuron. Depolarization The specific period during which potassium ions diffuse out of the neuron due to a change in membrane permeability. This period occurs at the end of action potential and limits the speed at which nerve impulses can be generated in a nerve fibre. how many stomach compartments are in a ruminant animal? D) Cells with gap junctions use chemical synapses C. 11 Involved in control of rhythmic activities such as breathing. ________ potentials are short-lived, local changes in membrane potential that can be either depolarized or hyperpolarized. 2.) channels at the presynaptic end, which in turn promotes fusion of diffusion of K+ out of the axon through gated ion channels. Other neurotransmitters stimulate a net efflux of positive charge (usually in the form of K+ diffusing out of the cell), leaving the inside of the membrane more negative. First, diffusion of the neurotransmitter across the synaptic cleft takes approximately 0.05 millisecond. A second nerve impulse cannot be generated until ________. True or False, The oligodendrocytes can myelinate several axons. The stimulus can be a chemical, electrical, or mechanical signal. Which result of the stimulus applied is the likely cause of the Temperature directly correlates with the transmission of nerve impulses. Are the heads on a 98 and 99 v8 5.7L the same? The action potential is +40 mV. 0.80.80.8 liters He pushes off the boards with a force of 9.0 N. What is his resulting acceleration? When a sensory neuron is excited by some form of energy, the resulting graded potential is called a(n) ________. The channels often allow ions to diffuse in both directions, but some gated channels restrict transmission to only one direction. These ions are propagated inside and outside the cell through specific sodium and potassium pumps present in the neuron membrane. Which of the following is not a function of the autonomic nervous system? The sympathetic and parasympathetic are subdivisions of the ________. The generation of a second action in some neurons can only A second nerve impulse cannot be generated until _____. job of the oligodendrocyte. You'll get a detailed solution from a subject matter expert that helps you learn core concepts. Does Berkekey accept transcripts with a W on it. answer choices all sodium gates are closed proteins have been resynthesized the Na ions have been pumped back into the cell the membrane potential has been reestablished Question 2 30 seconds Q. c) the relapse of neurotransmitter molecules gives cells the property of being electrically coupled This leaves 0.30 to 3.80 milliseconds for other processes. b) an excitatory postsynaptic potential occurs if the excitatory effect is greater than the inhibitory effect but less than threshold Select the correct statement regarding synapses. 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 Two factors are essential for the release of the neurotransmitter from the presynaptic terminal: (1) depolarization of the terminal and (2) the presence of calcium ions (Ca2+) in the extracellular fluid. response observed in the left graph? As a result, the action potential signal "jumps" along the axon membrane from node to node rather than spreading smoothly along the membrane, as they do in axons that do not have a myelin sheath. the membrane potential has been reestablished. The ions may attach to the membranes of synaptic vesicles, in some way facilitating their fusion with the nerve terminal membrane. synaptic vesicles to the axonal membrane. It is a short duration of time during which a new nerve impulse cannot be generated in a neuron, after initiation of a previous action potential. The neuron cannot respond to a second stimulus, no matter how strong. B) are crucial in the production of neurotransmitters, C) are crucial for the development of neural connections. A second nerve impulse cannot be generated until _____. A second nerve impulse cannot be generated until ________. There is space between the pre-synaptic neuron and post-synaptic neuron which is known as synaptic cleft or synaptic gap. The synaptic cleft prevents an impulse from being transmitted directly from one neuron to another. Schwann cells are functionally similar to ________. If you're ready to pass your A-Level Biology exams, become a member now to get complete access to our entire library of revision materials. Involved in activating fibers of a skeletal muscle such as B) Current is directly proportional to the voltage. A neuron that has as its primary function the job of connecting other neurons is called a(n) _____. The nerve goes through a brief refractory period before racing resting potential. a. Dendrites- Receive the signals from the axon ends. 3.) After neurotransmitter is released from the presynaptic terminal, it diffuses across the synaptic cleft and binds to receptor proteins on the postsynaptic membrane. When a stimulus is applied to resting membrane, sodium ions freely pass inside the cell and membrane is now said to be in depolarized phase. The fastest conduction velocity occurs in the largest diameter nerve fibres. When the voltage has the required number of electron particles it conducts current. movement of Ca2+ into the interior of the axonal terminus B) open ion channels to provoke rapid responses. Sodium is the principal ion in the fluid outside of cells, and potassium is the principal ion in the fluid inside of cells. 4.) Others are membrane proteins that, upon activation, catalyze second-messenger reactions within the postsynaptic cell; these reactions in turn open or close the ion channels. The signal finally reaches the target cell where it shows a response. The frequencies of the alleles A and a are 0.60.60.6 and 0.40.40.4, respectively, in a particular plant population. It can be generated when a neurons membrane potential is changed by chemical signals from a nearby cell. They are generated when the nerve 6.) ________ is a disease that gradually destroys the myelin sheaths of neurons in the CNS, particularly in young adults. This results in a huge influx of sodium ions inside the cells which trigger the nerve impulse conduction. A) the membrane potential has been reestablished B) the Na ions have been pumped back into the cell C) proteins have been resynthesized D) all sodium gates are closed. A) Subthreshold stimulusB) Temporal summationC) Spatial If a membrane depolarization does not reach the threshold level, an action potential will not happen. interior is ________. Second, they are taken back into the presynaptic terminal by transmitter-sensitive transport molecules. Beginning at the resting potential of a neuron (for instance, 75 mV), a local potential can be of any grade up to the threshold potential (for instance, 58 mV). This series of activations, by propagating the action potential along the fibre with virtually no reduction in amplitude, gives the nerve impulse its regenerative property. C) motor fibers that conduct nerve impulses from the CNS to smooth muscle, cardiac muscle, and glands. postsynaptic neuron by many terminals at the same time.3.) c) glial cell Due to the high concentration of sodium ions inside the axoplasm, the potassium channels will open. the membrane potential has been reestablished. C) brain, spinal cord, and peripheral nerves, Which of the following neurotransmitters inhibits pain and is The nerve impulse travels across the membrane of the axon in the form of an electrical signal. Vesicle membranes are then recovered from the plasma membrane through endocytosis. The period after an initial stimulus when a neuron is not sensitive to another stimulus is the ________. This expulsion process is called exocytosis. Select the correct statement about synapses. The interior is ________. 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). The transmitter molecules are then expelled from the vesicles into the synaptic cleft. Transmission takes place through gap junctions, which are protein channels that link the cellular contents of adjacent neurons. b) association neuron A nerve impulse is similar to a lightning strike. The sodium-potassium pump is a mechanism of active transport that moves sodium ions out of cells and potassium ions into cells. a) sodium gates in the membrane can open in response to electrical potential changes Unipolar neurons have axons structurally divided into peripheral and The sheath of Schwann is also called the ________. A second nerve impulse cannot be generated until ____ the membrane potential has been reestablished Saltatory conduction is made possible by ________. 2.) Both a nerve impulse and a lightning strike occur because of differences in electrical charge, and both result in an electric current. True or False, In myelinated axons the voltage-regulated sodium channels are concentrated at the nodes of Ranvier. Due to nerve impulse, the resting potential is changed to an action potential to conduct signals to the target in response to a stimulus. Neurons sense the changes in the environment and as a result, generate nerve impulses to prepare the body against those changes. 3.) 3.) A-level Biology focuses on providing students, tutors and teachers with detailed revision materials for A-Level Biology. d) leakage channel, What is the role of acetylcholinesterase? True or False, Action potentials can be generated by virtually all cells of the body because all cells possess cell membranes. cord and sensory ganglia of cranial nerves? In the resting state, the membrane potential becomes electro-negatively charged due to the movement of positively charged potassium ions outside the cell and the presence of electro-negative proteins in the intracellular space. Strong stimuli cause a) destroy ACh a brief period after its release by the axon endings negatively charged and contains less sodium. A second nerve impulse cannot be generated until ________. If you consider the axon as an electrical wire or loop, nerve impulse that travels along the axon as current, and the charged particles ( sodium and potassium ions) as the electron particles then the process can be understood quite easily. When the action potential is over (after transmitting the nerve impulse through neuron) the cell membrane potential returns back by repolarizing the membrane. In electrical synapses, two neurons are connected through channel proteins for transmitting a nerve impulse. True or False, Voltage is always measured between two points and may be called the potential between these two points. other types of channels and can fire multiple action potentials to The first channels to open are the sodium ion channels, which allow sodium ions to enter the cell. Which of the following is correct? During the repolarization state, efflux of potassium ions through the potassium channel occurs. a) the synaptic cleft prevents an impulse from being transmitted directly from one neuron to another concentrated at the nodes of Ranvier. zoneD) Secretory regionE) Trigger zone. conduction states that the whole nerve cell must be stimulated for Some synapses are purely electrical and make direct electrical connections between neurons. 16. It delays the process of conducting signals because it uses a higher number of ion channels to alter the resting state of the neuron. (c) Find the minimum product of sums. Recordings from squid synapses and neuromuscular junctions of the frog reveal a delay of 0.5 to 4.0 milliseconds between the onset of action potential at the nerve terminal and action potential at the postsynaptic site. The interaction of competing EPSPs and IPSPs at the hundreds or even thousands of synapses on a single neuron determines whether the nerve impulse arriving at the presynaptic terminals will be regenerated in the postsynaptic membrane. 4 shows the change in potential of the axon membrane during an action potential. d) oligodendrocytes, David N. Shier, Jackie L. Butler, Ricki Lewis, Charles Welsh, Cynthia Prentice-Craver, David Shier, Jackie Butler, Ricki Lewis, Human Anatomy and Physiology Laboratory Manual (Main Version). However, some neurotransmitters have relatively consistent effects on other cells. What is the role of acetylcholinesterase? sc.7.L.15.2. 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. One incoming fiber triggers responses in ever-increasing numbers c) neurolemma Saltatory conduction is made possible by ________. A second nerve impulse cannot be generated until _____. The nerve goes through a brief refractory period before racing resting potential. Which of the following is a good example of a neuromodulator? Which of the following is not a D) Cells with gap junctions use chemical synapses, The period after an initial stimulus when a neuron is not sensitive c) sensory neurons that convey information from somatic receptors in the head, body wall, and limbs and from receptors from the special senses of vision, hearing, taste, and smell to the CNS

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