| baseline foetal heart rate | <paediatrics> The average heart rate for a particular foetus during the diastolic phase of uterine contractions. (05 Mar 2000) |
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| baseline variability of foetal heart rate | The beat-to-beat changes in foetal heart rate as recorded on a graph. (05 Mar 2000) |
| rate, heart | Number of heart beats per minute. The normal resting adult heart beats regularly at an average rate of 60 times per minute. (young children's hearts beat faster). The speed of the heartbeat (heart rate) is governed by the speed of electrical signals from the pacemaker of the heart, the sa node, located in the right atrium (upper chamber of the heart). The electrical signals from the sa node travel across the atria and cause these two upper heart chambers to contract, delivering blood into the lower heart chambers, the ventricles. The electrical signals then pass through the av node to reach the ventricles. Electrical signals reaching the ventricles cause these chambers to contract, pumping blood to the rest of the body, generating the pulse. During rest, the speed of electrical signals originating from the sa node is slow, so the heart beats slowly. During exercise or excitement, the speed of signals from the sa node increases, and the heartbeat quickens. (12 Dec 1998) |
| heart rate | The number of beats per minute. Normal resting heart rates are variable with age, sex, size and overall cardiovascular condition. Heart rate can be determined by taking the pulse. Normal heart rate for an average sized adult is in the range of 60-85 beats/minute. (27 Sep 1997) |
| heart rate, foetal | The heart rate of the foetus. The normal range at term is between 120 and 160 beats per minute. (12 Dec 1998) |
| foetal heart rate | In the foetus, the number of heart beats per minute, normally 120 to 160. (05 Mar 2000) |
| maximum | 1. The greatest possible or actual effect or quantity. 2. The acme of a disease or process. (18 Nov 1997) |
| maximum breathing capacity | The volume of air breathed when an individual breathes as deeply and as quickly as possible for a given time (e.g., 15 sec.). Synonym: maximum breathing capacity. (05 Mar 2000) |
| maximum occipital point | The point on the squama of the occipital bone farthest from the glabella. (05 Mar 2000) |
| maximum permissible dose | <radiobiology> Defined by the International Commission on Radiological Protection as the greatest dose of radiation which, in the light of present knowledge, is not expected to cause detectable bodily injury to a person at any time during his lifetime. This dose has been reduced with each Commission report. The MPD is given in terms of acute or chronic exposure of the whole body or of organs, systems, or regions of the body, and differs for persons who are occupationally exposed versus the public at large. (05 Mar 2000) |
| maximum permissible exposure level | The highest level of exposure to a substance, usually noxious, in the environment or during diagnostic and therapeutic procedures, that a body can tolerate without injury. (12 Dec 1998) |
| maximum temperature | In bacteriology, denoting a temperature above which growth will not take place. (05 Mar 2000) |
| maximum urea clearance | The urea clearance when the urine flow exceeds 2 ml/min; normal value is about 75 ml blood/min per 1.73 m2 body surface area. (05 Mar 2000) |
| maximum velocity | The maximum rate of an enzyme-catalyzed reaction that can be achieved by progressively increasing the substrate concentration at a given enzyme concentration; in cases of substrate inhibition, Vmax is an extrapolated value in the absence of such inhibition; Cf.: Michaelis-Menten equation. The maximum initial rate of shortening of a myocardial fibre that can be obtained under zero load; used to evaluate the contractility of the fibre. (05 Mar 2000) |
| maximum voluntary ventilation | The volume of air breathed when an individual breathes as deeply and as quickly as possible for a given time (e.g., 15 sec.). Synonym: maximum breathing capacity. (05 Mar 2000) |