countercurrent exchange

(redirected from Counter-current heat exchange)

countercurrent exchange

a biological mechanism designed to enable maximum exchange between two fluids. The mechanism's effect is dependent on the two fluids flowing in opposite directions, and having a concentration gradient between them.

fluid ONE

high concentration → low concentration

fluid TWO

high concentration ← low concentration

Such mechanisms occur, for example, in oxygen exchange between water and the blood vessels in fish gills, and in the ascending and descending tubules of the LOOP OF HENLE in the mammalian kidney.

Collins Dictionary of Biology, 3rd ed. © W. G. Hale, V. A. Saunders, J. P. Margham 2005
References in periodicals archive ?
From the results obtained, it can be seen that the plate geometry with inlet and outlet valves inline with the microchannels along with two inlets and four outlets (for possible counter-current heat exchange operation) provides uniform flow distribution under a wide range of flow conditions.
New devices use counter-current heat exchange, which circulates the coolant in the opposite direction to blood flow to enhance the effectiveness of endovascular cooling.
The evaporation produces a cold, dense vapor which travels towards the input end of the tunnel, producing a counter-current heat exchange with incoming food.