Neuroscience: Electrical Signals of Nerve Cells ; Questions & Answers

1. Which type(s) of electrical signals occur(s) within the neural circuit for a spinal reflex? a. Receptor potential only b. Action potential only c. Synaptic potential only d. Receptor potential and action potential only e. Receptor potential, synaptic potential, and action potential Answer: e Textbook Reference: Electrical Signals of Nerve Cells 2. The resting membrane potential typically ranges from _______ to _______. a. –90 mV; 90 mV b. 40 mV; 90 mV c. 40 V; 90 V d. –40 mV; –90 mV e. 0 mV; 90 mV Answer: d Textbook Reference: Electrical Signals of Nerve Cells 3. An action potential occurs if current injected into a neuron _______ the neuron to reach _______ potential. a. depolarizes; synaptic b. hyperpolarizes; synaptic c. depolarizes; threshold d. hyperpolarizes; threshold e. hyperpolarizes; resting Answer: c Textbook Reference: Electrical Signals of Nerve Cells 4. How will a neuron respond to an injection of negative current? a. It will become hyperpolarized. b. It will have a positive electrical response. c. It will generate a single action potential. d. It will generate multiple action potentials. e. It will reach the threshold potential. Answer: a Textbook Reference: Electrical Signals of Nerve Cells 5. The amplitude of the action potential of a given neuron is a. larger in response to depolarizing currents of greater magnitude. b. dependent on the magnitude of the sensory stimulus. c. related to the number of synapses on the neuron. d. smaller if the resting potential of the neuron is lower. e. always the same. Answer: e Textbook Reference: Electrical Signals of Nerve Cells 6. Which stimulus is most likely to evoke an action potential? a. Small hyperpolarizing current pulse b. Large hyperpolarizing current pulse c. Small depolarizing current pulse d. Large depolarizing current pulse e. Microelectrode insertion Answer: d Textbook Reference: Electrical Signals of Nerve Cells 7. Subthreshold current injected into an axon flows _______ along the axon and _______ with distance from the site of injection. a. actively; remains constant b. actively; decays c. actively; grows d. passively; remains constant e. passively; decays Answer: e Textbook Reference: Long-Distance Transmission of Electrical Signals 8. What is the mechanism of action of most local anaesthetics? a. Hyperpolarize resting membrane potential of neurons b. Block glutamate receptors in excitatory synapses c. Enhance the activity of inhibitory synapses by acting on postsynaptic GABA receptors d. Block Na+ channels involved in the generation of action potentials e. Bind opiate receptors Answer: d Textbook Reference: Clinical Applications: Anaesthesia and Neuronal Electrical Signalling 9. Which statement about active ion transporters is true? a. They are selectively permeable to certain ions. b. They are functionally similar to ion channels. c. They allow ion movement down the concentration gradient. d. They move all ions against the concentration gradient. e. They move certain ions against the concentration gradient. Answer: e Textbook Reference: How Ion Movements Produce Electrical Signals