Gas exchange in the alveoli · 肺泡中的气体交换
| English | 中文 | Pinyin · 拼音 |
|---|---|---|
| diffusion/dɪˈfjuːʒn/ | 扩散 | kuò sàn |
| surface area/ˈsɜːfɪs ˈeərɪə/ | 表面积 | biǎo miàn jī |
| gas exchange/ɡæs eksˈtʃeɪndʒ/ | 气体交换 | qì tǐ jiāo huàn |
| concentration gradient/ˌkɒnsənˈtreɪʃn ˈɡreɪdɪənt/ | 浓度梯度 | nóng dù tī dù |
Where the air meets the blood
- The alveoli are where oxygen enters the blood and carbon dioxide leaves it.
- Their structure makes them brilliant exchange surfaces.
- The swap happens entirely by diffusion 扩散.
空气与血液相遇的地方
- 肺泡是氧气进入血液、二氧化碳离开它的地方。
- 它们的结构使它们成为出色的交换表面。
- 这个交换完全通过 扩散 发生。
Alveoli have a large surface area and very thin walls for fast gas exchange. · 肺泡有大的表面积和很薄的壁以便快速气体交换。
A large surface area, thin walls, a rich blood supply and a moist lining all speed up gas exchange. · 大的表面积、薄的壁、丰富的血液供应和潮湿的内衬都加快气体交换。
Why alveoli are ideal
- a very large total surface area 表面积 (millions of tiny sacs),
- very thin walls — alveolus and capillary each one cell thick → a tiny distance to cross,
- a rich blood supply from the capillary network,
- a moist lining, so gases dissolve before crossing.
Gas exchange 气体交换 between an alveolus and a capillary
为什么肺泡是理想的
- 一个非常 大的总表面积(数百万个微小的囊),
- 非常 薄的壁——肺泡和毛细血管各一个细胞厚 → 一个微小的穿过距离,
- 来自毛细血管网络的 丰富的血液供应,
- 一层 潮湿的内衬,所以气体在穿过前溶解。
一个肺泡和一条毛细血管之间的气体交换
At the alveolus · 在肺泡处
Tap each part. Oxygen and carbon dioxide swap across a wall just one cell thick, between the air and the blood. · 点击每个部分。氧气和二氧化碳穿过一个只有一个细胞厚的壁交换,在空气和血液之间。
Which feature makes alveoli good for gas exchange? · 哪个特征使肺泡擅长气体交换?
Large surface area, thin walls, a rich blood supply and a moist lining all speed up gas exchange. · 大的表面积、薄的壁、丰富的血液供应和潮湿的内衬都加快气体交换。
Match each alveolar feature to why it helps. · 把每个肺泡特征与它为什么有帮助配对。
Every alveolar adaptation makes diffusion faster — more area, shorter distance, steeper gradient. · 每个肺泡的适应都使扩散更快——更多面积、更短距离、更陡的梯度。
Diffusion of the gases
- Oxygen is high in the alveolar air, low in the blood — so it diffuses air → blood.
- Carbon dioxide is high in the blood, low in the air — so it diffuses blood → air to be breathed out.
- Both move down their concentration gradients 浓度梯度.
气体的扩散
- 氧气 在肺泡空气中高,在血液中低——所以它 空气 → 血液 扩散。
- 二氧化碳 在血液中高,在空气中低——所以它 血液 → 空气 扩散以被呼出。
- 两者都 沿它们的浓度梯度 移动。
Oxygen diffuses: · 氧气扩散:
Oxygen is higher in the alveolar air than in the blood, so it diffuses air → blood. · 氧气在肺泡空气中比在血液中高,所以它空气 → 血液扩散。
Carbon dioxide diffuses from the blood into the alveolar ______, to be breathed out. · 二氧化碳从血液扩散进肺泡 ______,以被呼出。
CO₂ is higher in the blood, so it diffuses blood → air and is then exhaled. · CO₂ 在血液中更高,所以它血液 → 空气扩散,然后被呼出。
Keeping exchange fast
- Breathing brings fresh air, keeping alveolar oxygen high and CO₂ low.
- Flowing blood carries gases away as fast as they cross.
- Both keep the concentration gradients steep, so diffusion stays rapid.
保持交换快速
- 呼吸 带来新鲜空气,保持肺泡氧气高、CO₂ 低。
- 流动的血液 把气体在它们穿过的同时带走。
- 两者都保持 浓度梯度陡峭,所以扩散保持快速。
Breathing and the flow of blood keep gas exchange fast because they: · 呼吸和血液的流动保持气体交换快速,因为它们:
Fresh air and moving blood keep concentrations different on each side, so the gradients stay steep. · 新鲜空气和流动的血液保持两侧的浓度不同,所以梯度保持陡峭。
You've got it
- alveoli: large surface area, thin walls (one cell each), rich blood supply, moist lining
- oxygen diffuses air → blood; carbon dioxide diffuses blood → air (down the gradients)
- breathing + blood flow keep the gradients steep, so exchange stays fast
你掌握了
- 肺泡:大表面积、薄壁(各一个细胞)、丰富的血液供应、潮湿 内衬
- 氧气 空气 → 血液扩散;二氧化碳 血液 → 空气扩散(沿梯度向下)
- 呼吸 + 血流 保持梯度 陡峭,所以交换保持快速