章节大纲

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  • 呼吸系统

    A person in white clothing stands on rocks, enjoying the fresh air by the seaside.

    Why do you breathe?
    ::你为什么呼吸?

    We breathe because we need oxygen. also releases carbon dioxide from our bodies into the air. The respiratory system is the body system that brings air containing oxygen into the body and releases carbon dioxide into the atmosphere . Recall that oxygen is needed to make ATP .
    ::呼吸系统是将含氧空气带入人体并将二氧化碳释放到大气中的身体系统。

    How We Breathe
    ::我们如何呼吸

    Most of the time, you breathe without thinking about it. Breathing is mostly an involuntary action that is controlled by a part of your brain that also controls your heart beat. If you swim, do yoga, or sing, you know you can control your breathing, however. Taking air into the body through the nose and mouth is called inhalation . Pushing air out of the body through the nose or mouth is called exhalation . The woman pictured below is exhaling before she surfaces from the pool water ( Figure ).
    ::大部分时间, 你都会不经思考就呼吸。 呼吸主要是由大脑的一部分控制的非自愿行动, 同时控制你的心脏跳。 如果你游泳, 做瑜伽, 或者唱歌, 你知道你可以控制你的呼吸。 通过鼻子和嘴巴将空气注入身体被称为吸入。 通过鼻子或嘴将空气从身体中推出, 叫做呼气。 下面所描绘的女人在她从池水(图示 ) 上浮之前就呼气了。

    A woman underwater is exhaling as she prepares to surface in a pool.

    Being able to control breathing is important for many activities, such as swimming. The woman in the photograph is exhaling as she exits the water.
    ::能够控制呼吸对游泳等许多活动都很重要,照片中的妇女从水中出来时正在呼气。

    How do lungs allow air in? Air moves into and out of the lungs by the movement of . The most important muscle in the process of breathing is the diaphragm , a sheet of muscle that spreads across the bottom of the rib cage. The diaphragm and rib muscles contract and relax to move air into and out of the lungs. During inhalation, the diaphragm contracts and moves downward. The rib muscles contract and cause the ribs to move outward. This causes the chest volume to increase. Because the chest volume is larger, the air pressure inside the lungs is lower than the air pressure outside. This difference in air pressures causes air to be sucked into the lungs. When the diaphragm and rib muscles relax, air is pushed out of the lungs. Exhalation is similar to letting the air out of a balloon.
    ::肺部如何允许空气进入? 空气通过呼吸过程中最重要的肌肉是隔膜。 呼吸过程中最重要的肌肉是隔膜。 隔膜和肋骨肌肉收缩, 放松空气进入和流出肺部。 吸入时隔膜和肋骨肌肉相互连接, 向下移动。 肋骨肌肉收缩, 导致肋骨向外移动。 这导致胸部体积增加。 由于胸腔体积较大, 肺内的空气压力低于外面的空气压力。 空气压力的这种差异导致空气吸入肺部。 当隔膜和肋骨肌肉放松时, 空气会从肺部被挤出。 抽气类似于气球释放空气。

    How does the inhaled oxygen get into the bloodstream? The exchange of gasses between the lungs and the happens in tiny sacs called alveoli . The walls of the alveoli are very thin and allow gases to pass though them. The alveoli are lined with capillaries ( Figure ). Oxygen moves from the alveoli to the blood in the capillaries that surround the alveoli. At the same time, carbon dioxide moves in the opposite direction, from capillary blood to the alveoli. The gases move by simple diffusion , passing from an area of high concentration to an area of low concentration. For example, initially there is more oxygen in the alveoli than in the blood, so oxygen moves by from the alveoli into the blood.
    ::吸入氧是如何进入血液的?肺部之间气体的交换,以及微小的囊状物中发生的情况,这些囊状物叫做 alveoli。 alveoli 的墙壁非常薄,允许气体通过它们。 alveoli 的衬里有刺青(Figure ) 。 氧气从藻类中流出,流到藻类周围的血管中的血液中。 同时, 二氧化碳向相反的方向移动, 从毛细的血液到藻类。 气体通过简单的扩散, 从高浓度地区传到低浓度地区。 例如, 最初, 藻类中的氧量比血液中的氧还要多, 所以氧会从藻类中流到血液中流出。

    Alveoli and capillaries, showing gas exchange in the respiratory system.

    During respiration, oxygen gets pulled into the lungs and enters the blood by passing across the thin alveoli membranes and into the capillaries. The alveoli are at the end of the long air passages.
    ::在呼吸期间,氧气被吸入肺部,通过薄的白叶膜进入血液,进入血管。

    Breathing and Respiration
    ::呼吸和呼吸

    The process of getting oxygen into the body and releasing carbon dioxide is called respiration . Sometimes breathing is called respiration, but there is much more to respiration than just breathing. Breathing is only the movement of oxygen into the body and carbon dioxide out of the body. The process of respiration also includes the exchange of oxygen and carbon dioxide between the blood and the cells of the body.
    ::将氧气注入身体和释放二氧化碳的过程被称为呼吸。 有时呼吸被称为呼吸,但呼吸比呼吸要多得多。呼吸只是氧气进入身体和二氧化碳从身体中流出。呼吸过程还包括血液和细胞之间氧和二氧化碳的交换。

    Further Reading
    ::继续阅读

    Summary
    ::摘要

    • The diaphragm and rib muscles contract when you inhale and relax when you exhale.
      ::隔膜和肋骨肌肉收缩 当你吸气 呼吸放松的时候
    • The process of getting oxygen into the body and releasing carbon dioxide is called respiration.
      ::将氧气注入体内 释放二氧化碳的过程 叫做呼吸

    Review
    ::回顾

    1. In what part of the lung does gas exchange occur?
      ::肺部哪一部分会发生气体交换?
    2. What causes the gases to move in the lungs during gas exchange?
      ::气体交换期间气体在肺部中流动的原因是什么?
    3. What is the difference between breathing and respiration?
      ::呼吸和呼吸有什么区别?