The Nervous System Quiz
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Questions and Answers

What happens when the action potential exceeds -55mV?

  • The neuron remains at resting potential.
  • Sodium ions exit the neuron.
  • The neuron fires. (correct)
  • K+ channels close immediately.
  • Which ion primarily flows into the neuron during the first phase of the action potential?

  • Ca2+ ions
  • Na+ ions (correct)
  • Cl- ions
  • K+ ions
  • What is the term for the travel of action potential along the axon?

  • Propagation (correct)
  • Transmission
  • Repolarization
  • Refractory period
  • What occurs during the refractory period of a neuron?

    <p>No action potential is possible.</p> Signup and view all the answers

    Which type of neuron is responsible for transmitting signals from sensory receptors to the central nervous system?

    <p>Sensory neurons</p> Signup and view all the answers

    What happens to K+ ions after the action potential leaves a specific point in the axon?

    <p>They are pumped out of the cell.</p> Signup and view all the answers

    How do neurons communicate with one another?

    <p>Via action potentials that propagate down their axons.</p> Signup and view all the answers

    In the context of neuron firing, how can the intensity of a stimulus affect the response?

    <p>It influences whether a neuron fires or does not fire.</p> Signup and view all the answers

    What are the two basic cells that make up the nervous system?

    <p>Glia and Neurones</p> Signup and view all the answers

    What is the approximate weight of the average human brain?

    <p>1.5 kg</p> Signup and view all the answers

    What is the potential difference of a neuron at rest, also known as resting potential?

    <p>-70 millivolts</p> Signup and view all the answers

    What substance covers the axon and helps in insulating the neuron?

    <p>Myelin sheath</p> Signup and view all the answers

    What happens when a neuron is activated and an action potential is generated?

    <p>A spike of positive charge occurs inside the neuron.</p> Signup and view all the answers

    Which ions move more easily in and out of neurons, influencing resting potential?

    <p>Potassium and Sodium</p> Signup and view all the answers

    How do the central nervous system and peripheral nervous system differ?

    <p>CNS includes the brain and spinal cord, while PNS consists of other nerves.</p> Signup and view all the answers

    What role do sodium pumps and leakage channels play in neurons?

    <p>They regulate the movement of sodium and potassium ions.</p> Signup and view all the answers

    Study Notes

    The Nervous System

    • Nervous system is made up of two main parts:
      • Central nervous system (CNS): Brain and spinal cord
      • Peripheral nervous system: All other nerves in the body
    • Brain is essential for behavior and weighs approximately 1.5kg
    • Two basic cell types make up the nervous system, including the brain:
      • Glia: Support functions in the nervous system
      • Neurones: Receive and transmit information via electrical pulses, enabling thinking, talking, and walking

    Neurones

    • Dendrites receive signals from other connected neurones
    • Axon transmits information from dendrites to other neurones, covered by a fatty substance called Myelin sheath
    • Myelin sheath is semi-permeable, allowing some chemicals to enter or exit, but not ions. Ions can travel through ion channels
    • Potential difference between inside and outside of the cell changes when a neuron is activated. This difference is measured in millivolts (mV)
    • Resting potential of a neuron is -70mV when inactive, meaning the inside is negatively charged due to more sodium ions (Na+) outside the membrane than potassium ions (K+) inside
    • Action potential is generated when potential difference changes beyond a limit, causing a spike of positive charge inside the neuron.
    • Neuron fires when action potential exceeds -55mV
    • Action potential travels along the axon like a wave

    Neuron Firing

    • Sodium (Na+) ions flood into the cell when action potential reaches a location
    • Potassium (K+) ions are pumped out immediately after the action potential leaves
    • Not all stimuli lead to an action potential
    • Neuron firing is an 'all-or-none' process: either fires or doesn't fire
    • Intensity of stimulus is determined by the number of neurons firing

    Types of Neurones

    • Sensory neurones translate physical stimuli into electrical signals and transmit them to the central nervous system (CNS) via interneurons
    • Motor neurones send signals from the CNS to muscles or other body parts, carrying out the brain's desired movements
    • Interneurons connect within the CNS and with sensory and motor neurons

    Neuron Firing Features

    • Intensity of a stimulus influences the number of neurons firing, not the strength of a single neuron's firing.

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    Description

    Test your knowledge on the structure and function of the nervous system. This quiz covers the Central and Peripheral nervous systems, along with the roles of neurons and glial cells. Dive into the specifics of neuron communication and learn more about the brain's vital functions.

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