| acid wave | A temporary increase in the acidity of the urine occurring during fasting. Synonym: acid wave. (05 Mar 2000) |
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| alkaline wave | A period of urinary neutrality or even alkalinity after meals due to withdrawal of hydrogen ion for the purpose of secretion of the highly acid gastric juice. Synonym: alkaline wave. (05 Mar 2000) |
| alpha wave | Brain waves in the encephalogram which have a frequency of 8 to 13 per second. They are typical of the normal person awake and in a quiet resting state, and occur principally in the occipital region. (12 Dec 1998) |
| arterial wave | A wave in the jugular phlebogram due to transmission of carotid artery pulsation. B wave, the initial positive deflection in the electroretinogram, possibly arising from the inner nuclear layer of the retina. (05 Mar 2000) |
| A wave | The initial negative deflection in the electroretinogram, presumably reflecting retinal photoreceptor activity, an atrial deflection in an electrocardiogram recorded from within the atrium of the heart, the first positive deflection of the atrial and venous pulses due to atrial systole. (05 Mar 2000) |
| beta wave | <neurology> Brain waves in the electroencephalogram which have a frequency of 18 to 30 per second. They are typical during periods of intense activity of the nervous system, and occur principally in the parietal and frontal regions. (12 Dec 1998) |
| brain wave | Colloquialism for electroencephalogram. (05 Mar 2000) |
| brain wave complex | A specific combination of fast and slow electroencephalographic activity that recurs frequently enough to be identified as a discrete phenomenon. (05 Mar 2000) |
| brain wave cycle | The complete upward and downward excursion of a single wave, complex, or impulse as seen on an electroencephalogram. (05 Mar 2000) |
| brain wave test | <investigation> A diagnostic test which measures the electrical activity of the brain (brain waves) using high sensitive recording equipment attached to the scalp by fine electrodes. Commonly employed in the evaluation of neurological disease (for example seizures, epilepsy, etc.). Acronym: EEG (13 Nov 1997) |
| cannon wave | An exaggerated A wave in the jugular pulse caused by right atrial contraction occurring after ventricular contraction has closed the tricuspid valve, as in ventricular premature beats and in complete A-V block. (05 Mar 2000) |
| radio wave | <physics> Electromagnetic radiation with wavelengths of 300 millimetres or longer (even up to several kilometres). Radiation of this type is used to broadcast radio and television signals, and has frequencies up to thousands of megahertz (or one gigahertz). (09 Oct 1997) |
| recoil wave | The second rise in the tracing of a dicrotic pulse. Synonym: recoil wave. (05 Mar 2000) |
| V wave | <cardiology, physiology> A large pressure wave visible in recordings from either atrium or its incoming veins, normally produced by venous return but becoming very large when blood regurgitates through the A-V valve beyond the chamber from which the recording is made. (05 Mar 2000) |
| retrograde P wave | The P wave pattern in the electrocardiogram representing retrograde depolarisation of the atria, the impulse spreading from the A-V junction or the lower atrium upward. (05 Mar 2000) |