Name: how the body pushes air out
Uploaded: 2024-06-20T13:02:58.000Z
Duration: 1 min 23 s
Channel: JoVE

当吸气肌放松时，呼气开始，导致气体从传导区排出到体外环境。
膈肌松弛会导致胸膜腔收缩并对肺部施加压力。
随着肺容积减小，肺泡受到压缩，肺泡内压力升高。
当肺泡内压力超过大气压时，空气会流出。
胸膜腔为肺在呼吸过程中扩张和收缩提供了一个无摩擦的空间。
此外，呼气是由于肺部的弹性回缩所致，不涉及任何肌肉收缩。
在用力呼气过程中，腹肌推动膈肌向前，使胸腔收缩；同时，肋间内肌降低肋骨，减小胸腔容积。
呼气可以是自主的或非自主的。
在主动呼气过程中，肺部的气体以恒定速率被保持并释放，例如说话时的受控呼气。
相反，非自主呼气对代谢功能至关重要，不受意识控制，例如睡眠时的呼吸。

呼吸机制 ii：呼气

Mechanism of Breathing II: Expiration

呼气的生理学：无缝的呼吸过程

呼气是一个复杂的生理过程，随着吸气肌开始放松而开始。这种放松触发了一系列事件，这些事件体现了呼吸系统的效率。

呼气机制：

<ol style="margin: 12px;">
	<li>膈肌放松：作为这一过程中的关键参与者，当膈肌放松时，它会向上移动，从而减少胸腔的体积。这种关键肌肉的放松是呼气初始阶段的主要驱动力。</li>
	<li>胸膜压增加：膈肌松弛后，胸膜腔收缩。这种收缩会对肺部施加压力，导致肺容量减少。位于肋骨之间的肋间肌在呼气时也会收缩。这个动作将肋骨向下拉向内，进一步缩小胸腔的大小。</li>
	<li>肺泡受压：随着肺容量减少，肺泡受压，从而增加肺泡压力。该压力变得高于体外的大气压。</li>
	<li>气流流出肺部：较高的内部压力将空气从肺部排出，从而促进顺畅、轻松的流出。</li>
</ol>

胸膜腔是肺部和胸壁之间的空间，就像一个微调的舞台，在呼吸周期中适应肺部的有节奏的扩张和收缩。肌肉的力量和肺组织的自然弹性回缩也有利于呼气，有助于从肺部排出空气。

主动呼气：在剧烈呼吸或需要用力呼气的活动中，例如唱歌、演奏管乐器或举重等重体力消耗时，额外的肌肉会发挥作用：

<ul style="list-style-type: disc; margin-left: 35px;">
	<li>腹部肌肉：这些肌肉收缩，将膈肌进一步向上推，加剧胸廓体积的缩小。</li>
	<li>肋间内肌：这些肌肉有助于降低胸腔，进一步减少胸廓体积并有助于更有力地呼气。</li>
</ul>

自主呼气与非自主呼气：理解这种区别对于掌握呼吸过程的全部复杂性至关重要。

<ul style="list-style-type: disc; margin-left: 35px;">
	<li>自主呼气：这种类型的呼气，例如在讲话或唱歌时，涉及有意识地控制呼吸以精确调节气流。</li>
	<li>非自主呼气：这种自动过程对于维持生命至关重要，即使在睡眠期间，也无需有意识的努力即可连续运转。</li>
</ul>

呼吸机制 II：呼气

呼气的生理学：一个无缝衔接的呼吸过程
呼气，即呼出气体，是一个复杂的生理过程，始于吸气……

Education

教育

JoVE Core

Nursing

护理学

Unit 1

第一单元

Vital Signs: Respiration

生命体征：呼吸

KEY TERMS AND CONCEPTS

关键术语与概念

how the body pushes air out

Expiration is the process of pushing air out of the lungs. It begins when the inspiratory muscles relax. That relaxation starts a chain of changes in the chest and lungs.

As the diaphragm relaxes, it moves upward. This lowers the volume of the thoracic cavity, or chest space. The pleural cavity also contracts and presses on the lungs.

The intercostal muscles, which sit between the ribs, help during this phase too. They pull the ribs downward and inward. This makes the chest cavity even smaller. As lung volume drops, the alveoli, or tiny air sacs, are compressed.

When the alveoli are compressed, alveolar pressure rises. It becomes higher than the atmospheric pressure outside the body. Air then moves out of the lungs. The pleural cavity supports this rhythmic expansion and contraction, and the elastic recoil of lung tissue also helps exhalation.

Some expiration is active and needs extra muscle effort. This happens during forced breathing, such as singing, playing wind instruments, or heavy exercise like weightlifting. In these cases, the abdominal muscles push the diaphragm farther up, and the internal intercostal muscles lower the rib cage to make expiration more forceful.

Expiration can also be voluntary or involuntary. Voluntary expiration is under conscious control, such as during speech or singing, when airflow must be carefully regulated. Involuntary expiration happens automatically and continues without conscious effort, even during sleep.

How the Body Pushes Air Out

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How Air Moves Into the Lungs

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mechanism of breathing ii: expiration

Expiration is the process of pushing air out of the lungs. It begins when the inspiratory muscles relax. That relaxation starts a chain of changes in the chest and lungs. As the diaphragm relaxes, it moves upward. This lowers the volume of the thoracic cavity, or chest space. The pleural cavity also contracts and presses on the lungs. The intercostal muscles, which sit between the ribs, help during this phase too. They pull the ribs downward and inward. This makes the chest cavity even...

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Accessory Muscles That Support Breathing

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How Breathing Changes in Different Conditions

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Respiratory Signs to Check During Breathing

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assessment of ventilation i: respiratory rate

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Checking Breathing Patterns and Respiratory Rate

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assessment of ventilation ii: respiratory depth and rhythm

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Watching Breathing Depth and Rhythm

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Gas Exchange Checks in Respiratory Care

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respiratory volumes and capacities i

Breathing Rates and Pattern Changes

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alterations in respiration ii

Breathing Patterns and Their Clinical Meaning

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respiratory volumes

Measuring Lung Air Volumes

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respiratory capacities

Lung Capacity Measures in Breathing

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special considerations while measuring oxygen saturation

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Checking Breathing Rate and Oxygen Levels

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Respiratory Assessment Signs and Findings

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key terms and concepts

Learn how expiration works as the diaphragm relaxes, chest volume drops, and air leaves the lungs. Includes active breathing and voluntary vs. involuntary exhalation.

How the Body Pushes Air Out | JoVE K12

JoVE Core Nursing offers concise animated lessons on nursing practices, covering health systems, nursing organizations, and health concepts. It includes practical communication, infection prevention, and nursing fundamentals, providing students with a clear understanding of nursing principles.

nursing

How the Body Pushes Air Out

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