second nerve impulse CANNOT be generated until membrane potential has been reestablished 29 interior surface of a cell membrane of a resting (nonconducting) neuron differ from the external environment? B) are crucial in the production of neurotransmitters, C) are crucial for the development of neural connections. Select the correct statement regarding synapses. The synaptic cleft prevents an impulse from being transmitted directly from one neuron to another. neurons is called a(n) ________.A) afferent neuron, In myelinated axons the voltage-regulated sodium channels are 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. Temperature cause changes in the rate of diffusion of ions across the neuron membrane. This reverse polarity constitutes the nerve impulse. See answer (1) Copy. Which of the following describes the nervous system integrative function? A nerve impulse is produced when a stimulus acts on the nerve fibre, resulting in electrochemical changes across the nerve membrane. some types of Na+ channels inactivate at a positive potential and through voltage-gated channels. A neuron that has as its primary function the job of connecting other neurons is called a(n) ________. They are generated when the nerve d) cells with gap junctions use chemical synapses, the synaptic cleft prevents an impulse from being transmitted directly from one neuron to another, Which of the following is true about the movement of ions across excitable living membranes? Subthreshold Stimulus An insufficient stimulus Spatial Summation Due to this, a difference in electrical potential is generated across the membrane, known as nerve impulse or action potential. They increase amplitude as they move away from the stimulus point. One is the vertebrate neuromuscular junction, and the other is the giant synapse of the squid Loligo. (B). potentials?A) ligand-gated channel. 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. Because nerve impulses are not graded in amplitude, it is not the size of the action potential that is important in processing information within the nervous system; rather, it is the number and frequency with which the impulses are fired. Not ready to purchase the revision kit yet? b) opens K+ or Cl- channels b) association neuron The ions may attach to the membranes of synaptic vesicles, in some way facilitating their fusion with the nerve terminal membrane. Which of the choices below describes the ANS? What is the role of acetylcholinesterase? Automatically remove your image background. True or False, The oligodendrocytes can myelinate several axons. 3. The resulting increase in positive charge inside the cell (up to about +40 mV) starts the action potential. That is, the membrane potential has to reach a certain level of depolarization, called the threshold, otherwise, an action potential will not start. A) Subthreshold stimulusB) Temporal summationC) Spatial An inhibitory postsynaptic potential (IPSP) is associated with ________. ________.A) astrocytes B) microglia C) Schwann cells D) oligodendrocytes. This makes the process of nerve impulse faster as the nerve impulse does not travel the entire length of the axon ( this happens in case of continuous conduction). Select the correct statement regarding synapses. It causes the movement of ions both against the concentration gradient. What is certain is that when the concentration of Ca2+ is increased within the terminal, the probability of transmitter release is also increased. A) biogenic amine. What is the role of acetylcholinesterase? The nerve goes through a brief refractory period before racing resting potential. It delays the process of conducting signals because it uses a higher number of ion channels to alter the resting state of the neuron. An inhibitory postsynaptic potential (IPSP) is associated with It is called the action potential because the positive charge then flows through the cytoplasm, activating sodium channels along the entire length of the nerve fibre. spinal cord? The neurotransmitter molecules travel across the synaptic cleft and bind to receptors, which are proteins that are embedded in the membrane of the postsynaptic cell. Since ions cannot cross the lipid content of the myelin sheath, they spread passively down the nerve fibre until reaching the unmyelinated nodes of Ranvier. the membrane potential has been reestablished In what way does the interior surface of a cell membrane of a resting (nonconducting) neuron differ from the external environment? In this manner the action potential jumps quickly from node to node along the fibre in a process called saltatory conduction (from Latin saltare, to jump). Which of the following will occur when an excitatory postsynaptic 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 Collections of nerve cell bodies outside the central nervous system are called ________. 33) A second nerve impulse cannot be generated until _____. Owning to the importance of this discovery, he was awarded Noble Prize in 1932. a) sodium gates in the membrane can open in response to electrical potential changes First, the neurotransmitter molecules simply diffuse out of the narrow synaptic cleft. Due to this sheath, an action potential is not formed on the surface of the neuron. central processes. Which of the following is not characteristic of neurons? are crucial for the development of neural connections. A) motor neurons 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. d) ions always move from an area of higher concentration to an area of lower concentration, sodium gates in the membrane can open in response to electrical potential changes, Bipolar neurons are commonly ________. the membrane potential has been reestablished. A neural circuit in which a single impulse is transmitted over and over is a ________. A second nerve impulse cannot be generated until ________. A second nerve impulse cannot be generated until when? the amplitude of action potentials generated to increase. c) short distance hyperpolarization a) motor fibers that conduct nerve impulses from the CNS to smooth muscle, cardiac muscle, and glands d) motor fibers that conduct nerve impulses from the CNS to skeletal muscles, motor fibers that conduct nerve impulses from the CNS to smooth muscle, cardiac muscle, and glands, Saltatory conduction is made possible by ________. Strong stimuli cause answer choices 1.) and participates in the generation and conduction of action For this, sodium voltage-gated channels open. As instantaneous as the opening of sodium channels at threshold potential is their closing at the peak of action potential. Everything that you need to pass A-level Biology: Factors Affecting the Speed of Nerve Impulse. The interior is ________. The neurons are said to be in resting phase when there is no nerve impulse. a) an inhibitory postsynaptic potential occurs if the inhibitory effect is greater than the excitatory, causing hyperpolarization of the membrane In electrical synapses, the synaptic gap is about 0.2nm which also favors faster nerve impulse conduction. This reverse polarity constitutes the nerve impulse. Transmission takes place through gap junctions, which are protein channels that link the cellular contents of adjacent neurons. 2.) This phenomenon has formed the basis for classifying mammalian nerve fibres into groups in order of decreasing diameter and decreasing conduction velocity. At the neuromuscular junction, brief depolarizations measuring no more than one millivolt can be observed in the postsynaptic muscle membrane, even when it is at rest. A second nerve impulse cannot be generated until ________. Direct-acting neurotransmitters ________. A) lowering the threshold for an action potential to occur. A neuron that has as its primary function the job of connecting other neurons is called a(n) ________. In what way does the interior surface of a cell membrane of a resting (nonconducting) neuron differ from the external environment? response observed in the left graph? If the stimulus is more than the threshold value, then it will generate a nerve impulse that will travel across the entire length of the axon. A) They increase amplitude as they move away from the stimulus point. Select the correct statement about synapses. receptor detects a foreign stimuli. For every two potassium ions that move inside the cell, three sodium ions are transported outside. b) ions always move passively across membranes These are nerve impulses that jump from one node to another and are seen only in myelinated nerve fibres. Which ion channel opens in response to a change in membrane potential and participates in generation and conduction of action potentials? In this type of nerve impulse conduction, the synaptic gap is more than electrical synapses and is about 10-20 nm. 4.) What does the central nervous system use to determine the strength of a stimulus? D) the membrane potential has been reestablished. The interior is ________. summationD) Threshold stimulus, The nodes of Ranvier are found only on myelinated, peripheral neuron processes. The first factor is the outside diameter of the nerve fibre. 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. In electrical synapses, two neurons are connected through channel proteins for transmitting a nerve impulse. These electrochemical changes cause depolarization of the membrane resulting in the generation of nerve impulses. 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There is space between the pre-synaptic neuron and post-synaptic neuron which is known as synaptic cleft or synaptic gap. the membrane potential has been reestablished. c) the relapse of neurotransmitter molecules gives cells the property of being electrically coupled What event is depicted in the structure labeled A? Select the correct answer for the following question: The substance released at axon terminals to propagate a nervous impulse is called a(n) ________. . function of astrocytes? C) found in ganglia Second, the response of the postsynaptic receptor takes about 0.15 millisecond. 4.) impulse would move to the axon terminal only, C) the impulse would move to the axon terminal only, and the muscle leakage gated channels 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. An inhibitory postsynaptic potential (IPSP) is associated with ________. D) Cells with gap junctions use chemical synapses C. 11 D) pumps three sodium ions outside the cell and two potassium ions inside. Following are some major factors that affect the speed of nerve impulse: Myelin sheath is present around the neuron and functions as an electrical insulator. In the polarized state, the axon membrane is more permeable to potassium ions instead of sodium ions and as a result, it causes rapid diffusion of potassium ions. 1.) In chemical transmission, a chemical substance called the neurotransmitter passes from one cell to the other, stimulating the second cell to generate its own action potential. As the axon diameter increase, the speed of nerve impulses increases as well. This results in the alternation in the electro-negativity of the membrane because the stimulus causes the influx of sodium ions (electropositive ions) by 10 times more than in the resting state. 0.80.80.8 liters 2.) (a) Plot the following function on a Karnaugh map. (In reference to the neuromuscular synapse, it is called the end-plate potential, or EPP.). An c) stimulate the production of acetylcholine In contrast to electrical transmission, which takes place with almost no delay, chemical transmission exhibits synaptic delay. 3.) the membrane potential has been reestablished. Saltatory conduction is made possible by ________. ________ is a neurotransmitter of the CNS that is used by Purkinje cells of the CNS. True or False, Chapter 11 Fundamentals of the Nervous System and Nervous Tissue (TB). 5) Different types of sensory input can have B) A nerve impulse occurs if the excitatory and inhibitory effects are equal. Signals are propagated along the nerve fibres in the form of nerve impulses. True or false: The all-or-none phenomenon as applied to nerve 2.) This process is called repolarization. negatively charged and contains less sodium. True or False, During depolarization, the inside of the neuron's membrane becomes less negative. Due to this, the transmission of nerve impulses is slower than electrical synapses. b) ganglia This period occurs at the end of action potential and limits the speed at which nerve impulses can be generated in a nerve fibre. potential (EPSP) is being generated on the dendritic membrane?A) Plasma membrane exhibits voltage-gated Ca2+ channels. a) nuclei Advertisement Advertisement This process requires ATP because the movement of ions is against the concentration gradient of both ions. Drag the appropriate labels to their respective targets. Na+ channels open: . Nerve Impulse is a major mode of signal transmission for the Nervous system. True or False, A graded potential that is the result of a neurotransmitter released into the synapse between two neurons is called a postsynaptic potential. This results in a huge influx of sodium ions inside the cells which trigger the nerve impulse conduction. The change in membrane potential results in the cell becoming depolarized. Saltatory is faster than continuous conduction and occurs in myelinated neurons. buffering potassium and recapturing neurotransmitters are 15. In chemical synapses, the conduction of nerve impulse occurs through chemical signals. Both of the ion channels then close, and the sodium-potassium pump restores the resting potential of -70 mV. Does Berkekey accept transcripts with a W on it. The generation of a second action in some neurons can only 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? Which of the following is not a function of the autonomic nervous system? How does this difference in electrical charge come about? During the repolarization state, efflux of potassium ions through the potassium channel occurs.