Muscle Physiology: Neuromuscular Transmission L2
44 Questions
0 Views

Choose a study mode

Play Quiz
Study Flashcards
Spaced Repetition
Chat to lesson

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

What is the location of the cell body of a motor neuron?

  • Muscle fibers
  • Peripheral nerves
  • Neuromuscular junction
  • Spinal cord or brainstem (correct)

    • What is the function of a motor neuron in relation to skeletal muscle fibers?

  • To transmit signals from the neuromuscular junction
  • To produce acetylcholine
  • To control the contraction of muscle fibers (correct)
  • To receive signals from muscle fibers

    • What is the term for the specialized synapse between a motor nerve ending and a muscle fiber?

  • Motor endplate
  • Neuromuscular junction (correct)
  • Motor unit
  • Synaptic knob

    • How many motor endplates are typically present on a single muscle fiber?

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

    What is the direction of transmission of electric impulses at the neuromuscular junction?

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

    What is the term for a motor nerve axon ending with up to 50 synaptic knobs/boutons?

    <p>Motor unit</p> Signup and view all the answers

    What is the primary function of a motor unit?

    <p>To control the contraction of multiple muscle fibers</p> Signup and view all the answers

    What characteristic of motor units allows for precise adjustments in force?

    <p>Recruitment and gradation of motor units</p> Signup and view all the answers

    What is unique about the motor units responsible for extraocular muscle function?

    <p>They have a small number of myofibers</p> Signup and view all the answers

    What happens when a motor neuron is activated?

    <p>All of the innervated muscle fibers contract simultaneously</p> Signup and view all the answers

    What is the primary factor determining the size of a motor unit?

    <p>The number of myofibers innervated</p> Signup and view all the answers

    What is the functional difference between motor units in the quadriceps muscle and those in extraocular muscles?

    <p>Quadriceps motor units are larger and control powerful movements</p> Signup and view all the answers

    What is the main component of the synaptic vesicles in the presynaptic terminal?

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

    What is the function of the active zone in the presynaptic terminal?

    <p>Holds synaptic vesicles in the right place</p> Signup and view all the answers

    What is the consequence of the binding of ACh to nicotinic receptors in the postsynaptic membrane?

    <p>Depolarization of the muscle fiber membrane</p> Signup and view all the answers

    What is the enzyme responsible for the degradation of ACh in the synaptic cleft?

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

    What is the clinical sign of botulism in animals?

    <p>Progressive motor paralysis</p> Signup and view all the answers

    What is the effect of organophosphate toxicosis on acetylcholinesterase?

    <p>Irreversible inactivation</p> Signup and view all the answers

    What is the role of the synaptic cleft in the neuromuscular junction?

    <p>Contains extracellular fluid and matrix molecules</p> Signup and view all the answers

    What is the consequence of the abnormal reduction in the number of Ach receptors on the neuromuscular endplate?

    <p>Exercise-induced weakness</p> Signup and view all the answers

    What is the function of the voltage-gated calcium channels in the presynaptic terminal?

    <p>Allow calcium to enter the presynaptic terminal</p> Signup and view all the answers

    What is the role of SNARE proteins in the neuromuscular junction?

    <p>Promote docking, fusion, and release of ACh by exocytosis</p> Signup and view all the answers

    What is the main function of a motor neuron in relation to muscle fibers?

    <p>To control the contraction of muscle fibers</p> Signup and view all the answers

    What is the term for the area of the muscle fiber membrane where a synapse occurs with a motor nerve axon?

    <p>Motor endplate</p> Signup and view all the answers

    What is the typical number of motor endplates present on a single muscle fiber?

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

    What is the role of acetylcholine in the neuromuscular transmission?

    <p>To facilitate the transmission of electric impulses</p> Signup and view all the answers

    What is the characteristic of the transmission of electric impulses at the neuromuscular junction?

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

    What is the term for the group of muscle fibers that can be controlled by a single motor neuron?

    <p>Motor unit</p> Signup and view all the answers

    What is the primary factor that determines the strength of muscle contraction?

    <p>Frequency of motor unit activation</p> Signup and view all the answers

    Which of the following muscles has motor units with a large number of myofibers?

    <p>Quadriceps muscle</p> Signup and view all the answers

    What is the characteristic of motor units that allows for precise adjustments in force?

    <p>Recruitment and gradation of force</p> Signup and view all the answers

    What is the consequence of activating a motor neuron?

    <p>All innervated muscle fibers contract simultaneously</p> Signup and view all the answers

    What is the functional difference between motor units in the quadriceps muscle and those in extraocular muscles?

    <p>Size of motor units</p> Signup and view all the answers

    What is the purpose of varying the number of motor units activated?

    <p>To make precise adjustments in force</p> Signup and view all the answers

    What is the shape of the presynaptic terminal at the neuromuscular junction?

    <p>Button-like</p> Signup and view all the answers

    Which proteins are responsible for holding the synaptic vesicles in the right place at the active zone?

    <p>Specific proteins</p> Signup and view all the answers

    What is the role of mitochondria in the presynaptic terminal?

    <p>To provide energy for the production and release of Acetylcholine</p> Signup and view all the answers

    What is the name of the receptors that bind to Acetylcholine and nicotine in the postsynaptic membrane?

    <p>Nicotinic receptors</p> Signup and view all the answers

    What is the result of the binding of Acetylcholine to its receptors in the postsynaptic membrane?

    <p>Depolarization of the muscle fiber</p> Signup and view all the answers

    What is the purpose of the subneural clefts in the synaptic cleft?

    <p>To increase the surface area for neurotransmitter binding</p> Signup and view all the answers

    What is the effect of botulinum toxin on the neuromuscular junction?

    <p>It destroys SNARE proteins</p> Signup and view all the answers

    What is the clinical sign of organophosphate toxicosis in animals?

    <p>All of the above</p> Signup and view all the answers

    What is the effect of the abnormal reduction in the number of Ach receptors on the neuromuscular endplate?

    <p>Exercise-induced weakness</p> Signup and view all the answers

    What is the role of Acetylcholinesterase in the synaptic cleft?

    <p>To break down Acetylcholine</p> Signup and view all the answers

    More Like This

    Use Quizgecko on...
    Browser
    Open
    Browser
    Browser