"muscle spindle" meaning in English

{
  "forms": [
    {
      "form": "muscle spindles",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
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      "args": {},
      "expansion": "muscle spindle (plural muscle spindles)",
      "name": "en-noun"
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  "lang": "English",
  "lang_code": "en",
  "pos": "noun",
  "senses": [
    {
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          "kind": "other",
          "name": "English entries with incorrect language header",
          "parents": [
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      "examples": [
        {
          "ref": "1974, Felix Beck, John Benjamin Lloyd, The Cell in Medical Science, page 536:",
          "text": "In conclusion, it must be emphasized that although we now know something of the detailed structure of the muscle spindle, and the functional properties of its component parts, the exact role or roles it plays in voluntary or reflex muscle ovements are still a matter for further speculation and experiment",
          "type": "quote"
        }
      ],
      "glosses": [
        "A stretch receptor within the body of a skeletal muscle that detects changes in the length of the muscle."
      ],
      "id": "en-muscle_spindle-en-noun-PVCb~Ak0",
      "wikipedia": [
        "muscle spindle"
      ]
    }
  ],
  "word": "muscle spindle"
}

{
  "forms": [
    {
      "form": "muscle spindles",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {},
      "expansion": "muscle spindle (plural muscle spindles)",
      "name": "en-noun"
    }
  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "noun",
  "senses": [
    {
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        "English countable nouns",
        "English entries with incorrect language header",
        "English lemmas",
        "English multiword terms",
        "English nouns",
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      ],
      "examples": [
        {
          "ref": "1974, Felix Beck, John Benjamin Lloyd, The Cell in Medical Science, page 536:",
          "text": "In conclusion, it must be emphasized that although we now know something of the detailed structure of the muscle spindle, and the functional properties of its component parts, the exact role or roles it plays in voluntary or reflex muscle ovements are still a matter for further speculation and experiment",
          "type": "quote"
        }
      ],
      "glosses": [
        "A stretch receptor within the body of a skeletal muscle that detects changes in the length of the muscle."
      ],
      "wikipedia": [
        "muscle spindle"
      ]
    }
  ],
  "word": "muscle spindle"
}