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  2. Gas exchange - Wikipedia

    en.wikipedia.org/wiki/Gas_exchange

    Gas exchange is the physical process by which gases move passively by diffusion across a surface. For example, this surface might be the air/water interface of a water body, the surface of a gas bubble in a liquid, a gas-permeable membrane, or a biological membrane that forms the boundary between an organism and its extracellular environment.

  3. Passive transport - Wikipedia

    en.wikipedia.org/wiki/Passive_transport

    Passive diffusion across a cell membrane.. Passive transport is a type of membrane transport that does not require energy to move substances across cell membranes. [1] [2] Instead of using cellular energy, like active transport, [3] passive transport relies on the second law of thermodynamics to drive the movement of substances across cell membranes.

  4. Knudsen diffusion - Wikipedia

    en.wikipedia.org/wiki/Knudsen_diffusion

    Knudsen diffusion, named after Martin Knudsen, is a means of diffusion that occurs when the scale length of a system is comparable to or smaller than the mean free path of the particles involved. An example of this is in a long pore with a narrow diameter (2–50 nm) because molecules frequently collide with the pore wall. [ 1 ]

  5. Filter feeder - Wikipedia

    en.wikipedia.org/wiki/Filter_feeder

    Krill feeding in a high phytoplankton concentration (slowed by a factor of 12). Filter feeders are aquatic animals that acquire nutrients by feeding on organic matters, food particles or smaller organisms (bacteria, microalgae and zooplanktons) suspended in water, typically by having the water pass over or through a specialized filtering organ that sieves out and/or traps solids.

  6. Discontinuous gas exchange - Wikipedia

    en.wikipedia.org/wiki/Discontinuous_gas_exchange

    During the closed phase of discontinuous gas exchange cycles, the spiracle muscles contract, causing the spiracles to shut tight. At the initiation of the closed phase, the partial pressure of both O 2 and CO 2 is close to that of the external environment, but closure of the spiracles drastically reduces the capacity for the exchange of gases with the external environment. [2]

  7. Paracellular transport - Wikipedia

    en.wikipedia.org/wiki/Paracellular_transport

    Paracellular transport refers to the transfer of substances across an epithelium by passing through the intercellular space between the cells. [1] It is in contrast to transcellular transport, where the substances travel through the cell, passing through both the apical membrane and basolateral membrane.

  8. Extracellular fluid - Wikipedia

    en.wikipedia.org/wiki/Extracellular_fluid

    Extracellular fluid is the internal environment of all multicellular animals, and in those animals with a blood circulatory system, a proportion of this fluid is blood plasma. [4] Plasma and interstitial fluid are the two components that make up at least 97% of the ECF. Lymph makes up a small percentage of the interstitial fluid. [5]

  9. Osmoregulation - Wikipedia

    en.wikipedia.org/wiki/Osmoregulation

    Osmoregulation is the active regulation of the osmotic pressure of an organism's body fluids, detected by osmoreceptors, to maintain the homeostasis of the organism's water content; that is, it maintains the fluid balance and the concentration of electrolytes (salts in solution which in this case is represented by body fluid) to keep the body fluids from becoming too diluted or concentrated.