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  • 案例研究:肌肉和运动

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    Case Study: Needing to Relax
    ::案例研究:需要放松

    This dog is expressing his interest in something — perhaps a piece of food — by using the  neck muscles to tilt its head in an adorable fashion. Humans also sometimes tilt their heads to express interest. But imagine how disturbing and painful it would be if your neck tilted involuntarily, without you being able to control it! Forty-three year old Edward unfortunately knows just how debilitating this can be.
    ::这只狗通过用颈部肌肉以可爱的方式倾斜头部,表达他对某种东西的兴趣,或许是一块食物。人类有时也倾斜头来表达兴趣。但想象一下,如果你的颈部非自愿倾斜,而你却无法控制它,那会是多么的令人不安和痛苦!不幸的是,43岁的爱德华知道这是多么的虚弱。

    Edward has a rare condition called cervical dystonia, which is also called spasmodic torticollis. In this condition, the muscles in the neck contract involuntarily, often causing the person’s head to twist to one side. The illustration shows one type of abnormal head positioning that can be caused by cervical dystonia. The muscles may contract in a sustained fashion, holding the head and neck in one position, or they may spasm repeatedly, causing jerky movements of the head and neck.
    ::Edward有一个罕见的情况,叫做宫颈性躁郁症,也被称为精神紧张症。 在这种情况下,颈部肌肉不自愿地结合,常常导致一个人的头部向一边扭曲。 插图显示了一种由宫颈性躁郁症可能造成的不正常头部定位。 肌肉可能持续萎缩,将头部和颈部放在一个位置,或者反复抽筋,造成头部和颈部的干燥动作。

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    Illustration from a medical book written around 1910, showing a person identified as having spasmodic torticollis (cervical dystonia)
    ::1910年前后撰写的一本医学书中的说明,其中显示一个人被确定患有精神紧张症(宫颈性抑郁症)

    Cervical dystonia is painful and can significantly interfere with a person’s ability to carry out their usual daily activities. In Edward’s case, he can no longer drive a car, because his uncontrollable head and neck movements and abnormal head positioning prevent him from navigating the road safely. He also has severe neck and shoulder pain much of the time. 
    ::子宫颈性痢疾是痛苦的,可以大大干扰一个人开展日常活动的能力。 就爱德华而言,他不能再驾驶汽车了,因为他无法控制头部和颈部的移动以及不正常的头部定位阻碍了他安全地上路。 他也经常有严重的颈部和肩部疼痛。

    Although it can be caused by an injury, there is  no known cause of cervical dystonia — and there is also no cure. Fortunately for Edward and other cervical dystonia sufferers, though, there is a treatment that can significantly reduce symptoms in many people. You may be surprised to learn that this treatment is the same substance which, when injected into the face, is used for cosmetic purposes to reduce wrinkles!
    ::幸运的是,对爱德华和其他宫颈癌患者来说,治疗可以大大降低许多人的症状。你可能会惊讶地得知,这种治疗是同一种物质,在被注射到脸上时,用于化妆目的,以减少皱纹!

    The substance is botulinum toxin, one preparation of which may be familiar to you by its brand name — Botox. It is a neurotoxin produced by the bacterium Clostridium botulinum , and can cause a life-threatening illness called botulism. However, when injected in very small amounts by a skilled medical professional, botulinum toxins have some safe and effective uses. In addition to cervical dystonia, botulinum toxins can be used to treat other disorders involving the muscular system, such as strabismus (misalignment of the eyes); eye twitches; excessive muscle contraction due to neurological conditions like  cerebral palsy; and even overactive bladder.
    ::肉毒毒素是一种肉毒毒素,一种制剂可能为你们所熟知,其品牌是肉毒毒素,是一种由细菌Clostridium botulinum生产的神经毒素,可造成一种叫肉毒杆菌的危及生命的疾病,但是,如果由熟练的医学专业人员少量注射,肉毒毒素有一些安全有效的用途,除了宫颈性痢疾之外,肉毒毒素还可用于治疗其他与肌肉系统有关的疾病,例如:斜眼(眼睛的不适);眼电动;由于脑麻痹等神经条件造成的肌肉过度收缩;甚至可被用于过活膀胱。

    Botulinum toxin has its effect on the muscular system by inhibiting muscle contractions. When used to treat wrinkles, it relaxes the muscles of the face, lessening the appearance of wrinkles. When used to treat cervical dystonia and other disorders involving excessive muscle contraction, it reduces the abnormal contractions.  
    ::肉毒杆菌毒素通过抑制肌肉收缩对肌肉系统产生影响。当用来治疗皱纹时,它会放松脸部的肌肉,减少皱纹的外观。当用来治疗宫颈溃疡和其他与肌肉过度收缩有关的疾病时,它会减少异常的收缩。

    In this chapter, you will learn about the muscles of the body, how they contract to produce movements and carry out their functions, and some disorders that affect the muscular system. At the end of the chapter, you will find out if botulinum toxin helped relieve Edward’s cervical dystonia, and how this toxin works to inhibit muscle contraction.
    ::在本章中,你将了解身体的肌肉,如何结合它们来产生运动和履行职能,以及影响肌肉系统的某些疾病。 在本章结尾,你将发现肉毒杆菌毒素是否有助于缓解爱德华的宫颈溃疡,以及这种毒素是如何抑制肌肉萎缩的。

    Chapter Overview: Muscular System
    ::章节概览:肌肉系统

    In this chapter, you will learn about the muscular system, which carries out both voluntary body movements and involuntary contractions of internal organs and structures. Specifically, you will learn about:
    ::在本章中,你们将了解肌肉系统的情况,它既进行自愿身体运动,又进行内部机关和结构的非自愿收缩。

    • The different types of muscle tissue — skeletal, cardiac, and smooth muscle —and their different characteristics and functions
      ::不同的肌肉组织类型——骨骼、心脏和光滑肌肉——及其不同的特征和功能
    • How muscle cells are specialized to contract and cause voluntary and involuntary movements
      ::肌肉细胞如何专门用于包装和造成自愿和非自愿行动
    • The ways in which muscle contraction is controlled
      ::控制肌肉收缩的方式
    • How skeletal muscles can grow or shrink, causing changes in strength
      ::骨骼肌肉如何成长或收缩,导致体力变化
    • The structure and organization of skeletal muscles — including the different types of muscle fibers — and how actin and myosin filaments move across each other, according to the sliding filament theory, to cause muscle contraction
      ::骨骨骼肌肉的结构和组织——包括不同类型的肌肉纤维——以及根据滑动丝丝理论,动作和髓纤维化如何相互移动,导致肌肉收缩
    • Cardiac muscle tissue in the heart that contracts to pump blood through the body
      ::心脏心脏心肌组织 将血液注入身体
    • Smooth muscle tissue that makes up internal organs and structures, such as the digestive system, blood vessels, and uterus
      ::构成内器官和结构(如消化系统、血管和子宫)的肌肉组织
    • The physical and mental health benefits of aerobic and anaerobic exercise, such as running and weight lifting
      ::运动和举重等有氧和厌氧锻炼的身心健康惠益
    • How individuals vary in their response to exercise.
      ::个人对行动的反应如何不同。
    • Disorders of the muscular system, including musculoskeletal disorders (such as strains and carpal tunnel syndrome) and neuromuscular disorders (such as muscular dystrophy, myasthenia gravis, and Parkinson’s disease)
      ::肌肉系统紊乱,包括肌肉骨骼紊乱(如菌株和骨干隧道综合症)和神经肌肉系统紊乱(如肌肉萎缩、脑膜炎和帕金森病)

    As you read the chapter, think about the following questions:
    ::当你读到该章时,请考虑以下问题:

    1. How is the contraction of skeletal muscles controlled?
    ::1. 如何控制骨骼肌肉收缩?

    2. Botulinum toxin works on the cellular and molecular level to inhibit muscle contraction. Based on what you learn about how muscle contraction works, can you think of some ways it could potentially be inhibited?
    ::2. 肉毒杆菌毒素在细胞和分子一级进行工作,以抑制肌肉收缩,根据你对肌肉收缩如何起作用的了解,你能想出某种可能抑制肌肉收缩的方法吗?

    3. What is one disorder involving a lack of sufficient muscle contraction? Why does it occur?
    ::3. 一种缺乏足够肌肉收缩的疾病是什么?为什么会发生?