| maximal expiratory flow-volume curve | <chest medicine> Curves depicting maximal expiratory flow in liters/second at each point of lung inflation (expressed in liters or percentage of forced vital capacity) during a forced vital capacity determination. Common abbreviation is mefv. (12 Dec 1998) |
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| peak expiratory flow | The maximum flow at the outset of forced expiration, which is reduced in proportion to the severity of airway obstruction, as in asthma. (05 Mar 2000) |
| peak expiratory flow rate | Measurement of the maximum rate of airflow attained during a forced vital capacity determination. Common abbreviations are pefr and pfr. (12 Dec 1998) |
| positive end-expiratory pressure | A technique used in respiratory therapy in which airway pressure greater than atmospheric pressure is achieved at the end of exhalation by introduction of a mechanical impedance to exhalation. (05 Mar 2000) |
| negative end-expiratory pressure | A subatmospheric pressure at the airway at the end of expiration. (05 Mar 2000) |
| expiratory | <physiology> Pertaining to, or employed in, the expiration or emission of air from the lungs; as, the expiratory muscles. Source: Websters Dictionary (01 Mar 1998) |
| expiratory centre | The region of the medulla oblongata that is electrically active during expiration and where electrical stimulation produces sustained expiration. (05 Mar 2000) |
| expiratory dyspnea | Difficulty with the expiratory phase of breathing, often due to obstruction in the larynx or large bronchi, such as by a foreign body. (05 Mar 2000) |
| expiratory reserve volume | The extra volume of air that can be expired with maximum effort beyond the level reached at the end of a normal, quiet expiration. Common abbreviation is erv. (12 Dec 1998) |
| expiratory resistance | Resistance to flow of gas out of the lungs or the total resistance to flow of gas during the expiratory phase of the respiratory cycle. (05 Mar 2000) |
| expiratory stridor | A singing sound due to the semi-approximated vocal folds offering resistance to the escape of air. (05 Mar 2000) |
| zero end-expiratory pressure | Airway pressure which, at the end of expiration, equals atmospheric pressure. (05 Mar 2000) |
| brilliant vital red | Trisodium salt of a sulfonated diazo dye (a ditolyl group diazotised to sulfonated aminonaphthalene residues), used as a vital stain. Synonym: brilliant vital red. (05 Mar 2000) |
| vital | 1. Belonging or relating to life, either animal or vegetable; as, vital energies; vital functions; vital actions. 2. Contributing to life; necessary to, or supporting, life; as, vital blood. "Do the heavens afford him vital food?" (Spenser) "And vital virtue infused, and vital warmth." (Milton) 3. Containing life; living. "Spirits that live throughout, vital in every part." 4. Being the seat of life; being that on which life depends; mortal. "The dart flew on, and pierced a vital part." (Pope) 5. Very necessary; highly important; essential. "A competence is vital to content." (Young) 6. Capable of living; in a state to live; viable. "Pythagoras and Hippocrates . . . Affirm the birth of the seventh month to be vital." (Sir T. Browne) Vital air, oxygen gas; so called because essential to animal life. <physiology> Vital capacity, the breathing capacity of the lungs; expressed by the number of cubic inches of air which can be forcibly exhaled after a full inspiration. Vital force. <biology> See Tripod. <botany> Vital vessels, a name for latex tubes, now disused. See Latex. Origin: F, fr. L. Vitalis, fr. Vita life; akin to vivere to live. See Vivid. Source: Websters Dictionary (01 Mar 1998) |
| vital centre | Centre essential to life; usually refers to the centres located in the medulla oblongata which are necessary for the maintenance of respiration and circulation. (05 Mar 2000) |