R radiography the use of electromagnetic radiation to create images of the body from which medical diagnoses can be made. Initially referred to ‘plain’ X-ray films but the general term…
L labyrinthitis inflammation of the inner ear resulting in disturbance of balance and co-ordination. Dizziness, nausea and loss of balance, especially on head movement, are the commonest symptoms and these…
P pacemaker the region of the heart, normally the sinoatrial node, that rhythmically initiates the cardiac action potential and hence the whole electrical and mechanical cardiac cycle, varying the heart…
E ear the structures concerned with hearing and also with balance and posture. (1) The external ear leads to the tympanic membrane (eardrum) which separates it from (2) the middle…
O obesity a condition in which body fat stores are enlarged to an extent which impairs health. Develops when food intake is in excess of energy requirements. The most common…
C caffeine occurs naturally in the leaves, seeds or fruits of more than 60 different plants, including coffee beans, kola nuts (cola) and tea leaves, and is also added to…
Z zinc see minerals; appendix 4.3. zone of optimal functioning (ZOF) in sport psychology, a model of optimal performance, proposed in 1980 by Russian psychologist Yuri L Hanin, that hypothesizes…
Y Yerkes–Dodson law see inverted-U hypothesis. yips a movement disorder that can affect sports performers, seen particularly in golfers but also in cricketers and darts players, involving uncontrollable movements of…
K keratitis inflammation of the cornea, the transparent part of the outer coat of the eyeball – the ‘window’ in front of the the iris and the pupil. Organisms do…
X X-rays short-wavelength electromagnetic ionizing radiation, which can penetrate the body structures to varying degrees. Discovered in 1895 by Wilmhelm Röntgen, a German physicist (the very first X-ray photograph showed…
