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EMG and Muscle Physiology - Anatomy & Physiology

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이 집합의 용어 (15)

  • What does an Electromyogram (EMG) measure?
    An EMG measures the electrical signals produced by contracting skeletal muscle cells.
  • Define a motor unit in the muscular system.
    A motor unit is a motor neuron and all of the muscle fibers that it controls; it is the functional unit of the muscular system.
  • How is a whole muscle composed in terms of motor units?
    A whole muscle is composed of many motor units, with each neuron activating all muscle cells in its motor unit simultaneously.
  • Characteristics of small motor units?
    Small motor units control few muscle fibers per neuron and allow for fine, precise control, such as in the face and hands.
  • Characteristics of large motor units?
    Large motor units control many muscle fibers per neuron and are used for powerful but imprecise movements, like those in the back and thighs.
  • What is muscle tone (tonus)?
    Muscle tone is the state where muscles are always slightly contracted, keeping them firm, healthy, and ready to respond to stimulation.
  • How can muscle tone be observed in an EMG?
    Muscle tone appears as a wavy baseline during an EMG recording.
  • What are graded contractions in muscles?
    Graded contractions refer to the ability of whole muscles to produce a range of force from weak to strong by varying motor unit recruitment.
  • What is multiple motor unit summation?
    It is the process where a stronger stimulus recruits more motor units simultaneously to increase muscle contraction strength.
  • How does temporal summation affect muscle contraction?
    Temporal summation changes the frequency of stimulus, causing motor units to contract more often and increase contraction strength.
  • Why do muscles use different combinations of motor units?
    To produce varying strengths of contraction depending on the required force, such as gentle versus powerful movements.
  • What is the functional significance of motor units in muscle control?
    Motor units allow precise control of muscle force by varying the number and frequency of motor units activated.
  • Example of a muscle with small motor units for fine control?
    Muscles in the face and hands have small motor units for fine, precise movements.
  • Example of a muscle with large motor units for powerful movements?
    Muscles in the back and thighs have large motor units for powerful but less precise movements.
  • How does the nervous system vary muscle contraction strength?
    By changing the number of motor units recruited and the frequency of their activation.