Physiology Quiz: Reflex Acts and Neural Circuits
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Questions and Answers

What is the function of acetylcholine in the neuromuscular junction?

  • To release neurotransmitters in the synaptic cleft (correct)
  • To store adenosine triphosphate
  • To bind to receptors on the presynaptic membrane
  • To store oxygen for cellular respiration

    • Which of the following is NOT a part of a neuromuscular junction?

  • A space filled with synovial fluid (correct)
  • The end of a single nerve cell which touches the sarcolemma of the muscle fibre
  • The synaptic cleft - a fluid-filled space
  • The sarcolemma of the muscle fibre

    • What is the process by which acetylcholine is released from the synaptic vesicles?

  • Diffusion
  • Osmosis
  • Endocytosis
  • Exocytosis (correct)

    • What is required for muscle contraction?

    <p>Adenosine triphosphate - a compound with high energy phosphate linkages</p> Signup and view all the answers

    Where is acetylcholine bound in the neuromuscular junction?

    <p>To the receptors on the sarcolemma of the muscle fibre</p> Signup and view all the answers

    What is the correct description of the neuromuscular junction?

    <p>The end of a single nerve cell which touches the sarcolemma of the muscle fibre</p> Signup and view all the answers

    Which of the following statements accurately describes the release of neurotransmitters?

    <p>Neurotransmitters are released from the terminal buttons of the presynaptic neuron axon and cross the synaptic gap.</p> Signup and view all the answers

    What is the role of acetylcholine in the nervous system?

    <p>Acetylcholine is released by neurons that innervate skeletal muscles at the neuromuscular junction.</p> Signup and view all the answers

    Which of the following statements about serotonin is TRUE?

    <p>Serotonin plays a role in mental functions and the regulation of sleep cycles.</p> Signup and view all the answers

    Which of the following neurotransmitters is known to inhibit the activity of certain neurons?

    <p>Gamma aminobutyric acid (GABA), primarily found in the encephalon.</p> Signup and view all the answers

    Which of the following neurotransmitters belong to the class of catecholamines?

    <p>Noradrenaline and dopamine.</p> Signup and view all the answers

    Which of the following statements BEST describes the function of excitatory postsynaptic potentials (EPSPs)?

    <p>EPSPs increase the likelihood of an action potential occurring in the postsynaptic neuron.</p> Signup and view all the answers

    What is the primary function of the myelin sheath in the nervous system?

    <p>To increase the speed of signal transmission along the axon.</p> Signup and view all the answers

    What is the process by which a neuron receives and transmits a signal?

    <p>A signal is received at the dendrites, transmitted along the axon, and then released at the axon terminal.</p> Signup and view all the answers

    Which statement about reflex acts is true?

    <p>It is initiated by a sensory neuron receiving a stimulus.</p> Signup and view all the answers

    What describes a resting neuron?

    <p>It is polarized due to charge differences across its membrane.</p> Signup and view all the answers

    What initiates a nervous impulse?

    <p>Altering ion distribution within a nerve cell.</p> Signup and view all the answers

    What is the correct definition of a synapse?

    <p>The connection between two neurons.</p> Signup and view all the answers

    What term describes the synapse between a neuron and a muscle cell?

    <p>Neuromuscular synapse</p> Signup and view all the answers

    Which statement about neurotransmitters is accurate?

    <p>They transmit signals across synapses.</p> Signup and view all the answers

    Which is part of the process of generating an action potential?

    <p>The influx of sodium ions following a stimulus.</p> Signup and view all the answers

    Which component is NOT involved in the resting state of a neuron?

    <p>Depolarization from external stimuli.</p> Signup and view all the answers

    Study Notes

    Reflex Act

    • A reflex act can be automatic and unconscious without involving the encephalon or a mental activity
    • A typical example of a reflex act is the patellar reflex
    • The reflex act represents the anatomic base of certain neural circuits

    Resting Neuron

    • A resting neuron is polarised because the internal and external surface of its membrane have opposite electrical charges
    • Its cytoplasm has a negative electric charge, and the external surface of its membrane has a positive electric charge

    Nervous Impulse

    • A nervous impulse originates in an electrochemical event triggered by the altered ion distribution in the nerve cell
    • It is transmitted and is also called action potential
    • When it is generated, a stimulus changes the resting potential by opening sodium channels and allowing the passage of sodium ions into the nerve cell

    Synapse

    • A synapse is the junction between two neurons (a presynaptic one and a postsynaptic one)
    • The synapse between a neuron and a muscle cell is called a neuromuscular synapse or neuromuscular junction

    Neurotransmitters

    • Neurotransmitters are chemical substances belonging to different classes of compounds (catecholamines, amino acids, etc.)
    • They are released from the terminal buttons of the presynaptic neuron axon and cross the synaptic gap
    • Their connection to the postsynaptic membrane receptors generates an action potential in the postsynaptic neuron
    • Acetylcholine is released by neurons which innervate skeletal muscles at the point of the neuromuscular junction
    • Serotonin is a neurotransmitter present both in the encephalon and in the spinal cord, involved in certain mental functions or in the circadian rhythm
    • Gamma aminobutyric acid (GABA) and glycine can inhibit the activity of certain neurons
    • Dopamine, noradrenaline, and adrenaline belong to the class of catecholamines

    Neuromuscular Junction

    • A neuromuscular junction consists of the end of a single nerve cell which touches the sarcolemma of the muscle fibre
    • Acetylcholine is released in the synaptic cleft of the neuromuscular junction and binds to the receptors on the cellular membrane of the muscle fibre (sarcolemma)
    • Muscle contraction requires acetylcholine as a neurotransmitter and adenosine triphosphate

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    Description

    Test your knowledge of reflex acts, neural circuits, and sensory neurons with this quiz. Identify the true statements about reflex acts and more.

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