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  • General

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  • 消化系统

    Collage of smiling mouths, emphasizing the importance of the mouth in digestion.

    What's the first step in the digestion process?
    ::消化过程的第一步是什么?

    It all starts with the mouth. Food goes in, you chew it up, swallow it, then what happens? The process of turning that food into energy and and other things necessary for life begins. But it all starts with the mouth.
    ::食物从嘴开始。食物进入,你把它嚼碎,吞下去,然后会发生什么?把食物变成能量和生命所必需的其他东西的过程开始。但是这一切都从嘴开始。

    The Start of Digestion: Mouth to Stomach
    ::消化的开始: 向斯托马赫口吐口水

    Does the sight or aroma of your favorite food make your mouth ? When this happens, you are getting ready for digestion .
    ::你最喜欢的食物的视觉或芳香 是否让你的嘴?

    Mouth
    ::嘴唇

    The mouth is the first digestive organ that food enters. The sight, smell , or taste of food stimulates the release of digestive by salivary glands inside the mouth. The major salivary enzyme is amylase . It begins the chemical digestion of by breaking down starch into sugar.
    ::口腔是食物进入的第一种消化器官。 食物的视觉、嗅觉或味道刺激了口腔内口腔口腔腺的消化。 主要的唾液酶是氨基酶。 它通过将淀粉分解成糖开始化学消化。

    The mouth also begins the process of mechanical digestion . Sharp teeth in the front of the mouth cut or tear food when you bite into it (see Figure ). Broad teeth in the back of the mouth grind food when you chew. Food is easier to chew because it is moistened by saliva from the salivary glands. The tongue helps mix the food with saliva and also helps you swallow. After you swallow, the chewed food passes into the pharynx .
    ::嘴部也开始机械消化过程; 嘴口前的尖牙在咬入嘴前切开或撕裂食物(见图); 嘴后长牙在咀嚼时磨食物; 食物更容易咀嚼,因为口腔的唾液使食物潮湿; 舌头有助于将食物与唾液混合,也帮助你吞咽; 吞咽后,嚼食的食物会进入阴道。

    A person about to bite into a wrap, demonstrating mechanical digestion in the mouth.

    Teeth are important for mechanical digestion.
    ::牙齿对机械消化很重要。

    Esophagus
    ::Esophagus( 以硫磷)

    From the pharynx, the food moves into the esophagus . The esophagus is a long, narrow tube that passes food from the pharynx to the stomach by peristalsis . The esophagus has no other digestive functions. At the end of the esophagus, a muscle called a sphincter controls the entrance to the stomach. The sphincter opens to let food into the stomach and then closes again to prevent food from passing back into the esophagus.
    ::食道是一条长而狭窄的管子,通过长而狭窄的管子,将食物从食道传递到胃部。食道没有其它消化功能。在食道的尽头,一个叫“螺旋杆”的肌肉控制着胃的入口。止血管打开了食物进入胃部,然后再次关闭,以防止食物返回食道。

    Stomach
    ::胃

    The stomach is a sac-like organ in which food is further digested both mechanically and chemically. (To see an animation of how the stomach digests food, go to the link below.) Churning movements of the stomach’s thick, muscular walls complete the mechanical breakdown of food. The churning movements also mix food with digestive fluids secreted by the stomach. One of these fluids is hydrochloric acid. It kills in food and gives the stomach the low (acidic) pH needed by digestive enzymes that work in the stomach. The main enzyme is pepsin , which chemically digests protein.
    ::胃部是一种类似盐的器官,其食物在机械和化学上都进一步消化。 (看看胃部如何消化食物的动画,到下面的环节。 )胃部厚厚的肌肉壁的突变使食物的机械破裂完全完整。 发酵运动还把食物与胃中隐藏的消化液混合在一起。 这些液体之一是盐酸。 它在食物中死亡,使胃部的消化酶所需的低(酸)pH(pH)为胃部的消化酶所需要。 主要的酶是pepsin,化学消化蛋白。

       

     

    The stomach stores the partly digested food until the is ready to receive it. When the small intestine is empty, a sphincter opens to allow the partially digested food to enter the small intestine.
    ::胃部储存部分消化的食物,直到可以接受。 当小肠空的时候,一个螺旋杆打开,让部分消化的食物进入小肠。

    Further Reading
    ::继续阅读

    Summary
    ::摘要

    • Digestion consists of mechanical and chemical digestion.
      ::消化由机械和化学消化组成。
    • Mechanical digestion occurs in the mouth and stomach.
      ::口腔和胃部发生机械消化。
    • Chemical digestion occurs mainly in the small intestine.
      ::化学消化主要发生在小肠中。
    • The pancreas and liver secrete fluids that aid in digestion.
      ::胰腺和肝脏分泌液 有助于消化

    Review
    ::回顾

    1. What is amylase and what is its role?
      ::什么是氨基苯,其作用是什么?
    2. Describe functions of the stomach.
      ::描述胃部的功能。
    3. What is pepsin?
      ::是什么?