Concept explainers
Mark the following statements as true or false. If a statement is false, correct it to make a true statement.
a. The resting membrane potential refers to the voltage difference across the membranes of excitable cells at rest.
b. The concentration of
c. The
d. A depolarization is a change in membrane potential that makes the potential less negative.
e. A local potential is a change in membrane potential that conducts the long-distance signals of the nervous system.
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Human Anatomy & Physiology
- Which of the following is TRUE regarding the absolute and relative refractory periods of the action potential (AP)? A. The absolute refractory period may be overcome if enough excitatory stimulation is applied to the neuronal membrane. B. The absolute refractory period is due the closing of the activation gate of voltage gated sodium channels at the peak of the AP. C. The relative refractory period is due to the closing of the activation gate of voltage gated potassium channels during the overshoot phase of the AP. D. The relative refractory period is due the closing of the inactivation gate of voltage gated sodium channels . E. All of the above statements are FALSE.arrow_forwardMatch the description with the statement that best describes the following statements hyperpolarization repolarization depolarization A. usually corresponds to opening of voltage-gated potassium channels B. any change in the membrane potential that moves the membrane potential to a value more positive than the resting potential (eg from -70mV to +35mV) C. any change in the membrane potential that moves the membrane potential to a value more negative than the resting potential (eg from -70mV to -85mV)arrow_forwarddescribe what the resting membrane potential of a cell is. What is the resting membrane potential of neurons (give units)? What are the two factors that generate the resting membrane potential? Think of scenarios that change the factors that generate the resting membrane potential and how that would change the overall resting membrane potential.arrow_forward
- Describe the contribution of each of the following to the establishment and maintenance of membrane potential: Part A Na+K+ Pump Passive movement of K+ across the membrane Passive movement of Na+ across the membrane Part B Resting membrane potential is approximately -70mV. Explain what resting membrane potential is and what -70mV refers to.arrow_forwardAnswer the following questions in regards to chemically gated ion channels in neurons: a. What is the chemical signal received by these channels? b. Where on the neuron will you find these channels? c. Describe how these channels open and close in response to a chemical stimulus.arrow_forwardThe presence of an electrical gradient is responsible for both the resting membrane potential and the action potential in the neuron.a. In this case who is responsible for maintaining the electric gradient to produce a potential for the resting membrane?b. Explain what is meant by an electrical gradient in the context of a cell (neuron)!arrow_forward
- Which of the following statements is false regarding the directions that forces of the eletrochemical gradient are pointing for each ion. Assume the membrane of the neuron is at rest. A. For chloride ions the electrostatic and diffusion forces are pointing in opposite directions. B For sodium ions the eletrostatic and diffusion forces are pointing in the same direction. C. For potassium ions the eletrostatic and diffusion forces are pointing in opposite directions. D. All options choices are TRUE regarding the forces of the electrochemical gradient on each ion. E. For calcium ions the electrostatic and diffusion forces are pointing in opposite directions.arrow_forwardRefer to the graph showing the course of an action potential. Which of the numbered points along the graph represent the time when voltage-gated potassium channels are first activated? a) 1 b) 2 c) 3 d) 4 e) 5arrow_forwardWhich of the following statements is TRUE of the action potential? A. At the peak of the action potential there are approximately an equal amount of open voltage gated sodium and potassium channels B. To reach threshold the action potential requires the activity of sodium potassium pump C. During the rising phase (prior to the peak) of the action potential more voltage gated sodium channels are open than voltage gated potassium channels D. None of the choice options are TRUE of the action potential E. The overshoot phase (below resting membrane potential) is a result of voltage gated sodium channels taking a long time to close.arrow_forward
- The resting membrane potential…A) Can be approximated using the Goldman-Hodgkin-Katz equation.B) Represents a difference in charges across the cell membrane, resulting mostly from the passive flow of Na+ions.C) Has no influence on the driving force that acts on different ions across the cell membrane.D) Is equally dependent on the concentration gradients of potassium and sodium across the cell membrane.E) Becomes hyperpolarized during an excitatory graded potential.arrow_forwardDraw details of the repolarization phase of an action potential from the following descriptions of the sequences of AfterHyperPolarization (AHP) and AfterDePolarization (ADP) sequences. Make the distinct phases clear and noticeable (5 % each) A complex AHP consisting of a first component AHP, an ADP, and a second component AHP before repolarization to resting membrane potential a first fast AHP component, followed by a slower AHP, followed by a fast ADP, and a second late AHP component before repolarization to restarrow_forwardThe inside negative membrane potential is a force that helps support... a.) the movement of (neutral) nonelectrolytes into the cell b.) the movement of cations into the cell c.) the movement of (neutral) nonelectrolytes out of the cell d.) the movement of anions into the cellarrow_forward
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