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Questions and Answers

What type of nervous tissue primarily contains cell bodies and dendrites?

  • Myelinated tissue
  • Gray matter (correct)
  • Spinal cord tissue
  • White matter
  • How does white matter primarily function in the central nervous system?

  • It facilitates voluntary control.
  • It processes sensory information.
  • It stores memory.
  • It carries information to and from the brain. (correct)
  • What is the primary consequence of damage in the thoracic region of the spinal cord?

  • Paraplegia (correct)
  • Quadriplegia
  • Loss of fine motor skills
  • Sensory deprivation in the arms
  • Which structure serves as the largest part of the brain?

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

    What type of axons are found predominantly in white matter?

    <p>Myelinated axons</p> Signup and view all the answers

    In a cross section of the spinal cord, where is white matter located?

    <p>Surrounding the central canal</p> Signup and view all the answers

    What does quadriplegia result from?

    <p>Damage to the cervical spinal cord</p> Signup and view all the answers

    What type of axons does gray matter predominantly contain?

    <p>Short, unmyelinated axons</p> Signup and view all the answers

    Which type of neuron carries nerve signals from a sensory receptor to the CNS?

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

    What role do interneurons play in the nervous system?

    <p>Receive input from sensory neurons and communicate with motor neurons</p> Signup and view all the answers

    Which structure of the neuron contains the nucleus and other organelles?

    <p>Cell body</p> Signup and view all the answers

    What is the primary function of a motor neuron?

    <p>Send nerve impulses away from the CNS to effector organs</p> Signup and view all the answers

    Which part of a neuron is primarily responsible for conducting nerve impulses?

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

    What are individual axons referred to as?

    <p>Nerve fibers</p> Signup and view all the answers

    What do dendrites do in a neuron?

    <p>Receive signals from sensory receptors or other neurons</p> Signup and view all the answers

    Which statement correctly describes efferent neurons?

    <p>Neurons that transmit signals from the CNS to effectors</p> Signup and view all the answers

    What is the primary function of the somatic system?

    <p>Serves the skin and skeletal muscles</p> Signup and view all the answers

    Which component initiates the reflex arc response?

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

    What is the role of the sympathetic division within the autonomic system?

    <p>Prepares the body for fight or flight responses</p> Signup and view all the answers

    What physiological state does the parasympathetic division promote?

    <p>Relaxed state, aiding digestion</p> Signup and view all the answers

    Which is true regarding reflex actions?

    <p>They can be both automatic and involuntary</p> Signup and view all the answers

    How do interneurons function in the reflex arc?

    <p>They connect sensory neurons to motor neurons</p> Signup and view all the answers

    What effect does the sympathetic division have on digestive organs?

    <p>Inhibits digestive functions</p> Signup and view all the answers

    Which of the following statements is true about voluntary and involuntary actions in the somatic system?

    <p>Some somatic motor actions are automatic.</p> Signup and view all the answers

    What is the term used for the minimum voltage that must be reached for an action potential to occur?

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

    During depolarization in an action potential, which ion primarily rushes into the cell?

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

    What characteristic of action potentials indicates that they do not vary in size?

    <p>They exhibit an all-or-nothing response.</p> Signup and view all the answers

    What happens during the repolarization phase of an action potential?

    <p>K+ channels open and Na+ moves out.</p> Signup and view all the answers

    Which of the following statements about action potentials is false?

    <p>Action potentials can vary in size.</p> Signup and view all the answers

    What restores the resting potential at the end of an action potential?

    <p>Sodium-potassium pump</p> Signup and view all the answers

    Which of the following describes the effect of increasing the stimulus strength on the action potential?

    <p>It does not change the size of the action potential.</p> Signup and view all the answers

    Where do action potentials occur in the neuron?

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

    What is the primary effect of alcohol on the brain?

    <p>Acts as a depressant</p> Signup and view all the answers

    What long-term effect does nicotine have on the body after initial use?

    <p>It raises blood sugar followed by a crash</p> Signup and view all the answers

    What percentage of individuals trying nicotine are likely to become addicted?

    <p>70%</p> Signup and view all the answers

    What is the typical duration of the euphoria experienced from cocaine use?

    <p>5 to 30 minutes</p> Signup and view all the answers

    What is a common follow-up feeling after the initial effects of methamphetamine wear off?

    <p>Agitation and violent behavior</p> Signup and view all the answers

    Which of the following is a significant health effect of long-term nicotine use?

    <p>Serious cardiovascular diseases</p> Signup and view all the answers

    Which neurotransmitter is primarily associated with nicotine's reinforcing effects?

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

    What psychiatric effects can follow the use of cocaine and crack?

    <p>Fatigue and irritability</p> Signup and view all the answers

    Study Notes

    Somatic System

    • Serves the skin and skeletal muscles
    • Somatic motor actions can be voluntary or involuntary
    • Reflexes are automatic responses to stimuli

    Reflex Arc

    • Sensory neurons enter the spinal cord and stimulate interneurons.
    • Interneurons synapse with motor neurons.
    • Motor neurons transmit signals to effectors, triggering a response to the stimulus.
    • Some interneurons relay signals to the brain for perception.

    Autonomic System

    • Regulates cardiac and smooth muscles, organs, and glands.
    • Divided into the sympathetic and parasympathetic divisions.
    • Both divisions create opposing responses and are involuntary.
    • Innervate all internal organs.

    Sympathetic Division

    • Active during emergency situations (fight or flight).
    • Increases heart rate and dilates airways for oxygen and glucose supply.
    • Inhibits digestive and urinary functions.

    Parasympathetic Division

    • Promotes relaxation and rest.
    • Enhances digestion and slows heart rate.
    • Often called the 'rest-and-digest' system.

    Gray and White Matter

    • Central Nervous System (CNS) consists of gray and white matter.
    • Gray matter contains cell bodies, dendrites, and short, unmyelinated axons.
    • White matter contains myelinated axons.

    Structure of the Spinal Cord

    • Cross-section shows a central canal, gray matter, and white matter.
    • Spinal nerves extend from the cord.
    • White matter surrounds gray matter and carries information to and from the brain.

    Functions of the Spinal Cord

    • Paralysis is a loss of sensation and voluntary control.
    • Paraplegia occurs with damage in the thoracic region, paralyzing lower body and legs.
    • Quadriplegia occurs with damage in the neck region, affecting all four limbs.

    The Brain

    • Composed of the cerebrum, diencephalon, cerebellum, and brain stem.
    • Cerebrum is the largest part of the brain.

    Anatomy of a Neuron

    • Sensory, inter, and motor neurons based on function.
    • Sensory neuron carries signals from sensory receptors to the CNS.
    • Sensory receptors detect environmental changes.

    Anatomy of a Neuron, continued

    • Interneurons are found only within the CNS.
    • They receive input from sensory neurons and other interneurons.
    • Interneurons process signals and communicate with motor neurons.

    Anatomy of a Neuron, continued

    • Motor neuron carries signals from the CNS to effectors (muscle fibers, organs, or glands).
    • Effectors carry out responses to environmental changes.

    Anatomy of a Neuron, continued

    • Neurons have cell body, dendrites, and an axon.
    • Cell body contains nucleus and other organelles.
    • Dendrites are short extensions that receive signals from receptors or other neurons.

    Anatomy of a Neuron, continued

    • Axon conducts nerve impulses.
    • Individual axons are called nerve fibers and collectively form a nerve.

    Action Potential

    • Nerve signals are action potentials.
    • Occur only in axons.
    • A stimulus activates the neuron, E.g., a pinprick on skin for pain neurons.
    • Threshold is the minimum voltage required for an action potential (-55 mV).

    Action Potential Continued

    • Action potentials are "all-or-nothing".
    • Once threshold is reached, the action potential completes.
    • Increasing stimulus strength does not change action potential size.

    Action Potential, continued

    • Depolarization: The first part of an action potential.
    • Na+ channels open and Na+ rushes into the cell, making the inside positive.
    • Repolarization: The second part of an action potential.
    • Na+ channels close and K+ channels open, letting K+ flow out of the cell, making the inside negative again.
    • The sodium-potassium pump restores resting potential by returning K+ inside and Na+ outside.

    Alcohol

    • Depressant on the brain.
    • Effects include relaxation, lowered inhibitions, impaired coordination, slurred speech, and vomiting.
    • High blood alcohol levels can lead to coma or death.

    Nicotine

    • Raises blood sugar, but the drop afterward causes cravings.
    • Stimulates dopamine release in pleasure centers, creating temporary pleasure.
    • 70% of users become addicted, and only 10-20% can quit.
    • Causes serious cardiovascular and respiratory diseases.

    Cocaine and Crack

    • Powerful stimulant.
    • Produces a short-lived sense of well-being, followed by fatigue, depression, and irritability.

    Methamphetamine and Ecstasy

    • Powerful stimulant often produced illicitly.
    • Creates euphoria, energy, alertness, and elevated mood.
    • Followed by agitation and sometimes violent behavior.

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    Description

    This quiz covers the fundamentals of the somatic and autonomic nervous systems, including their structures, functions, and responses. You will explore the differences between motor actions and reflex arcs, as well as the roles of the sympathetic and parasympathetic divisions in bodily responses. Test your understanding of how these systems interact with muscles, organs, and stimuli.

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