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Anatomy & Physiology vocabulary · Heart, Circulation and Breathing

Alveolus

Meaning in anatomy & physiology, with examples

/ælˈviːələs/nounCommon term

In anatomy & physiology, alveolus means: One of the millions of tiny air sacs at the ends of the airways in the lungs. Their thin walls are surrounded by capillaries, and this is where oxygen and carbon dioxide are exchanged.

In Turkish: alveol, hava keseciği

How it is used

Usually used in the plural: alveoli. Lectures mention type I cells, which form the thin wall, and type II cells, which make surfactant to stop the alveoli collapsing. The adjective is alveolar, as in alveolar air.

Example sentences

  1. Oxygen diffuses from the alveoli into the surrounding capillaries.

  2. Each alveolus has an extremely thin wall, which makes gas exchange fast.

Common collocations

  • alveoli
  • alveolar wall
  • alveolar air
  • surfactant
  • lungOne of the two spongy organs in the chest where oxygen passes from the air into the blood and carbon dioxide leaves it. The right lung has three lobes and the left lung has two.
  • gas exchangeThe movement of oxygen into the blood and carbon dioxide out of it by diffusion, across the walls of the alveoli and capillaries in the lungs, and between the blood and the tissues.
  • capillaryThe smallest type of blood vessel, with a wall only one cell thick. Capillaries connect arteries to veins, and oxygen, nutrients and waste pass through their walls to and from the tissues.
  • tracheaThe windpipe: the tube that carries air from the larynx down into the chest, where it divides into the right and left main bronchi. C-shaped rings of cartilage keep it open.
  • diffusionThe movement of particles from an area where they are more concentrated to an area where they are less concentrated, without the cell using energy. Oxygen enters the blood in the lungs this way.

More terms: Heart, Circulation and Breathing

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This page explains English vocabulary for learners. It is not medical advice.