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Anatomy & Physiology vocabulary · Physiological Processes

Diffusion

Meaning in anatomy & physiology, with examples

/dɪˈfjuːʒən/nounCommon term

In anatomy & physiology, diffusion means: The 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.

In Turkish: difüzyon, yayılma

How it is used

A passive transport process, compared in lectures with osmosis and active transport. Substances are said to diffuse down a concentration gradient. Facilitated diffusion uses protein channels or carriers but still needs no energy.

Example sentences

  1. Carbon dioxide moves out of the blood into the alveoli by diffusion.

  2. Glucose enters most cells by facilitated diffusion.

Common collocations

  • simple diffusion
  • facilitated diffusion
  • concentration gradient
  • rate of diffusion
  • diffuse across
  • osmosisThe movement of water across a selectively permeable membrane from a more dilute solution into a more concentrated one, until the two sides become more equal.
  • cell membraneThe thin, flexible layer that surrounds every cell and controls what enters and leaves it. It is made mainly of a double layer of phospholipids with proteins set into it.
  • 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.

This word in other fields

The same English word can have a different meaning in another field:

More terms: Physiological Processes

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