The meaning of the symbols of volume seen in a dream.

That fraction of the blood’s total volume made up of red cells. The packed cell volume is found by centrifuging blood in a tube and measuring the depth of the column of red cells as a fraction of the whole column of blood. (See also HAEMATOCRIT.)... packed cell volume

The additional amount of air that a person could breathe in or out if he or she were not using the full capacity of their LUNGS. (See also LUNG VOLUMES.)... reserve volume

The amount of air left in the LUNGS after an individual has breathed out as much as possible. It is a measure of lung function: for example, in a person with EMPHYSEMA the residual volume is increased. (See RESPIRATION; LUNG VOLUMES.)... residual volume

The volume of air within the LUNGS changes with the respiratory cycle (see RESPIRATION). The volumes de?ned in the following table can be measured, and may be useful indicators of some pulmonary diseases.

Normal values for a 60 kg man are (in ml):

Total lung capacity (TLC) The volume of air that can be held in the lungs at maximum inspiration.

Tidal volume (TV) The volume of air taken into and expelled from the lungs with each breath.

Inspiratory reserve volume (IRV) The volume of air that can still be inspired at the end of a normal quiet inspiration.

Expiratory reserve volume (ERV) The volume of air that can still be expired at the end of a normal quiet expiration.

Residual volume (RV) The volume of air remaining in the lungs after a maximal expiration.

Vital capacity (VC) The maximum amount of air that can be expired after a maximal inspiration.

Functional residual capacity (FRC) The volume of air left in the lungs at the end of a normal quiet expiration.... lung volumes

(FEV) the volume of air exhaled in a given period (usually limited to 1 second in tests of vital capacity). FEV is reduced in patients with obstructive airways disease and diminished lung volume.... forced expiratory volume

an apparent decrease in the visibility of a structure in a *cross-sectional imaging technique, such as CT or MRI, when either the thickness of the object is much less than that of the slice being used to make the image, or the object is only partially imaged within the slice. See artifact.... partial volume artifact

the amount of blood ejected from each ventricle on each contraction, which can be affected by medication, exercise, decreases in the volume of circulating blood, or heart anomalies. In a healthy adult, stroke volume is estimated at 70 ml.... stroke volume