Resting Membrane Potential Quiz
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Questions and Answers

What primarily establishes the resting membrane potential in excitable cells?

  • Active ion transport mechanisms alone
  • The equilibrium potential of Na⁺ exclusively
  • Ion concentration differences across the membrane (correct)
  • Electrical current flowing through the membrane

    • Which ion is most significant in contributing to the resting membrane potential due to its permeability?

  • Cl⁻
  • Na⁺
  • Ca²⁺
  • K⁺ (correct)

    • How does the Na⁺/K⁺ ATPase pump influence the resting membrane potential?

  • It increases intracellular Na⁺ concentration
  • It creates an excess of Ca²⁺ inside the cell
  • It decreases permeability of K⁺
  • It helps maintain ion concentration gradients (correct)

    • The resting membrane potential in most excitable cells typically ranges from:

    <p>–70 mV to –80 mV</p> Signup and view all the answers

    Which equation can be used to evaluate the contribution of each ion to the resting membrane potential?

    <p>Chord conductance equation</p> Signup and view all the answers

    Which ion has the least influence on the resting membrane potential due to its low permeability?

    <p>Na⁺</p> Signup and view all the answers

    What is the primary purpose of the Goldman equation in membrane potential analysis?

    <p>To evaluate each ion's contribution based on its relative permeability</p> Signup and view all the answers

    At rest, how do ions with higher conductance affect the membrane potential?

    <p>They push the potential towards their equilibrium potential</p> Signup and view all the answers

    What does homeostasis maintain within the body?

    <p>Stable balance among physiologic variables</p> Signup and view all the answers

    What is the definition of homeostasis in a physiological context?

    <p>A dynamic process of balance</p> Signup and view all the answers

    How do fluctuations in blood glucose levels relate to homeostasis?

    <p>They demonstrate homeostasis as a dynamic process</p> Signup and view all the answers

    What characterizes the exchange and communication processes in homeostasis?

    <p>They are essential for physiological work</p> Signup and view all the answers

    What is meant by the term 'set point' in relation to physiological variables?

    <p>An average value of a variable</p> Signup and view all the answers

    Why is the concept of dynamic constancy important in understanding homeostasis?

    <p>It reflects the ability of the body to fluctuate around an average</p> Signup and view all the answers

    What happens when homeostasis is not maintained?

    <p>Pathophysiology may occur</p> Signup and view all the answers

    What is a key concept in understanding physiological homeostasis?

    <p>Exchange and communication</p> Signup and view all the answers

    What is the primary function of local homeostatic responses?

    <p>To counteract changes in the internal or external environment</p> Signup and view all the answers

    What is the outcome of negative balance in homeostatic regulation?

    <p>Loss exceeds gain for a substance.</p> Signup and view all the answers

    What effect does active hyperemia have on vascular smooth muscle?

    <p>It promotes vasodilation in response to increased metabolism</p> Signup and view all the answers

    Which type of chemical messenger is involved in local cell communication?

    <p>Autocrine and paracrine substances</p> Signup and view all the answers

    Which statement accurately describes stable balance in homeostasis?

    <p>Losses and gains are equal.</p> Signup and view all the answers

    What primarily distinguishes neurons from other cells when transmitting signals?

    <p>The presence of neurotransmitters</p> Signup and view all the answers

    What is the importance of the National Academy of Sciences’ Recommended Daily Allowances (RDAs)?

    <p>They provide guidelines to avoid disease symptoms.</p> Signup and view all the answers

    What is the role of hormones in body communication?

    <p>They communicate with specific target cells via blood</p> Signup and view all the answers

    What can result from the disruption of homeostatic pathways?

    <p>Imbalance in nutrient levels.</p> Signup and view all the answers

    Which of the following is a key aspect of homeostasis described in the content?

    <p>Information flow is vital for coordinating physiological processes.</p> Signup and view all the answers

    Which factor does NOT trigger vasodilation in vascular smooth muscle during active hyperemia?

    <p>Lower hydrogen ion concentration</p> Signup and view all the answers

    What is a key characteristic of neurotransmitters?

    <p>They diffuse across the synaptic cleft to target cells</p> Signup and view all the answers

    How may increased protein intake affect health?

    <p>It can promote larger body size and increase cancer risk.</p> Signup and view all the answers

    What is required for homeostasis to be achieved?

    <p>Inputs must equal outputs.</p> Signup and view all the answers

    What aspect of communication do hormones primarily effect within the body?

    <p>Long-distance regulatory processes</p> Signup and view all the answers

    What limits the adjustments made within homeostasis?

    <p>The magnitude of inputs and outputs.</p> Signup and view all the answers

    What is the primary process by which the body maintains a relatively constant internal environment?

    <p>Homeostasis</p> Signup and view all the answers

    Which group of specialized cell types is primarily responsible for the transmission of signals in the body?

    <p>Neurons</p> Signup and view all the answers

    What does the term 'emergent properties' refer to in the context of complex biological systems?

    <p>Properties that occur from interactions between components</p> Signup and view all the answers

    What is the correct order of organization from cells to organ systems in the human body?

    <p>Cells → Tissues → Organs → Organ systems</p> Signup and view all the answers

    How many different types of cells can be identified in the human body?

    <p>200</p> Signup and view all the answers

    Which of the following statements about cell differentiation is true?

    <p>Cell differentiation transforms unspecialized cells into specialized cell types.</p> Signup and view all the answers

    Which of these components is NOT one of the four main functional groups of specialized cells?

    <p>Nervous tissue</p> Signup and view all the answers

    What role does the stretching of the cervix play during parturition?

    <p>It triggers a reflexive increase in uterine contractility.</p> Signup and view all the answers

    What is the primary focus of physiology in relation to living organisms?

    <p>Examining the mechanisms of living organisms</p> Signup and view all the answers

    How does fever function as an adaptive mechanism in response to infection?

    <p>By increasing the body's temperature set point to hinder pathogen proliferation.</p> Signup and view all the answers

    What is the primary function of feedforward regulation in physiological processes?

    <p>To anticipate changes and improve homeostatic efficiency.</p> Signup and view all the answers

    Which scenario exemplifies feedforward regulation in physiological responses?

    <p>Increase in metabolic heat production in response to cold temperatures.</p> Signup and view all the answers

    What can alter physiological set points in the body?

    <p>Changes in external conditions or internal physiological changes.</p> Signup and view all the answers

    What is an example of a variable that exhibits a rhythmic pattern in the body?

    <p>Body temperature variation throughout the day.</p> Signup and view all the answers

    Active product control plays a role in which of the following processes?

    <p>Inhibiting the rate-limiting enzyme in a chemical sequence.</p> Signup and view all the answers

    What contributes to the feedforward regulation observed in athletes before events?

    <p>Previous experiences influencing physiological responses.</p> Signup and view all the answers

    What maintains the constant temperature in a homeostatic control system despite fluctuations in environmental conditions?

    <p>A steady state requiring constant energy input</p> Signup and view all the answers

    How does a negative feedback system function in homeostasis?

    <p>It detects a deviation and counteracts it to return to the set point.</p> Signup and view all the answers

    What characterizes a positive feedback system compared to a negative feedback system?

    <p>It moves the variable away from the set point, accelerating change.</p> Signup and view all the answers

    What example is provided for negative feedback regulation within metabolic pathways?

    <p>Allosteric regulation via end-product inhibition.</p> Signup and view all the answers

    What is the primary aim of homeostatic control mechanisms?

    <p>To maintain stability in internal variables through balancing inputs and outputs.</p> Signup and view all the answers

    What happens when the internal variable exceeds the set point in a negative feedback system?

    <p>The system activates processes to reduce the variable toward the set point.</p> Signup and view all the answers

    What distinguishes steady state from static equilibrium in homeostatic systems?

    <p>Steady state is dynamic, involving energy input, while equilibrium is static.</p> Signup and view all the answers

    Which of the following mechanisms is primarily responsible for producing rapid and powerful effects in the body?

    <p>Positive feedback systems</p> Signup and view all the answers

    What primarily sustains the resting membrane potential in excitable cells?

    <p>Diffusion potentials from ion concentration gradients</p> Signup and view all the answers

    Which ion's high permeability at rest significantly influences the resting membrane potential?

    <p>K⁺</p> Signup and view all the answers

    How does the Na⁺/K⁺ ATPase pump contribute to the resting membrane potential?

    <p>By maintaining ion concentration gradients across the membrane</p> Signup and view all the answers

    In what way does the chord conductance equation analyze the resting membrane potential?

    <p>By weighing equilibrium potentials based on relative conductance</p> Signup and view all the answers

    Which of the following best explains why the resting membrane potential is close to the equilibrium potentials of K⁺ and Cl⁻?

    <p>These ions have high permeability at rest</p> Signup and view all the answers

    What characteristic of Na⁺ and Ca²⁺ impacts their role in the resting membrane potential?

    <p>Their low permeability at rest</p> Signup and view all the answers

    Which equation evaluates each ion's contribution based on relative permeability, as opposed to conductance?

    <p>Goldman equation</p> Signup and view all the answers

    Why do ions with lower conductance exert minimal influence on the resting membrane potential?

    <p>They have a negligible effect on voltage differences</p> Signup and view all the answers

    Study Notes

    Resting Membrane Potential

    • Resting membrane potential is the voltage difference across a cell membrane when it's not actively transmitting signals.
    • It's a crucial factor in excitable cells like nerves and muscles.
    • The potential is primarily established by diffusion potentials arising from ion concentration differences. Each ion tends to move the membrane toward its equilibrium potential.
    • Ions with higher permeability or conductance at rest have a larger impact on the membrane potential.
    • The typical range of resting membrane potential is -70mV to -80 mV in most excitable cells.

    Key Ion Contributions

    • Key ions at play include K+, Na+, Cl-, and Ca²+.
    • K+ and Cl- have high permeability at rest, bringing the membrane potential close to their respective equilibrium potentials.
    • Na+ and Ca²+, due to lower permeability, have less influence on the resting potential.
    • This difference in permeability accounts for the resting membrane potential in excitable cells.

    Measuring Ion Contributions

    • The chord conductance equation can be used to evaluate each ion's contribution to the membrane potential.
    • This equation considers equilibrium potentials and relative conductances (permeability) of each ion, weighting by their relative conductance (permeability).
    • The Goldman equation is another method, evaluating relative permeability instead of conductance.

    Na+/K+ ATPase Role

    • The Na+/K+ ATPase actively contributes to the resting membrane potential in two ways:
      • A direct electrogenic effect, where 3 Na+ ions are pumped out for every 2 K+ ions pumped in.
      • An indirect effect by maintaining the K+ concentration gradient, resulting in the K+ diffusion potential.
    • This gradient is crucial for the resting potential, and is maintained by the Na+/K+ pump.
    • The Na+/K+ pump also plays a part in establishing the action potential.
    • The Na+/K+ ATPase indirectly contributes to resting potential by contributing to a K+ concentration gradient.

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    Resting Membrane Potential PDF

    Description

    Test your knowledge on the resting membrane potential, a fundamental concept in cell biology crucial for understanding nerve and muscle function. This quiz examines the roles of key ions like K+, Na+, Cl-, and Ca²+ in establishing the membrane potential and how to measure their contributions. Challenge yourself to recognize how ion permeability affects cellular excitability!

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